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IN THE UNITED STATES PATENT AND TRADEMARK OFFICE 



In re Patent Application of Date: May 15, 2008 

Applicants: Bednorz et al. Docket: YO987-074BZ 

Serial No.: 08/479,810 Group Art Unit: 1751 

Filed: June 7, 1995 Examiner: M. Kopec 

For: NEW SUPERCONDUCTIVE COMPOUNDS HAVING HIGH TRANSITION 

TEMPERATURE, METHODS FOR THEIR USE AND PREPARATION 
Commissioner for Patents 
United States Patent and Trademark Office 
P.O. Box 1450 
Alexandria, VA 22313-1450 

APPEAL BRIEF 
PART IX 

CFR 37 §41 .37(c) (1) (ix) 

SECTION 1 



VOLUME 4 
Part 3 

BRIEF ATTACHMENTS F TO O 



Respectfully submitted, 



/Daniel P Morris/ 

Dr. Daniel P. Morris, Esq. 
Reg. No. 32,053 
(914) 945-3217 

IBM CORPORATION 
Intellectual Property Law Dept. 
P.O. Box 218 

Yorktown Heights, New York 10598 



BRIEF ATTACHMENT F 



IN THE UNITED STATES PATENT AND TRADEMARK OFFICE 



In re Patent Application of 
Applicants: Bednorz et al. 
Serial No.: 08/479,810 
Filed: June 7, 1995 



Date: March 1,2005 
Docket: YO987-074BZ 
Group Art Unit: 1751 
Examiner: M. Kopec 



For: NEW SUPERCONDUCTIVE COMPOUNDS HAVING HIGH TRANSITION 
TEMPERATURE, METHODS FOR THEIR USE AND PREPARATION 



Commissioner for Patents 
P.O. Box 1450 
Alexandria, VA 22313-1450 



In response to the Office Action dated July 28, 2004, please consider the 
following: 



FIRST SUPPLEMENTAL AMENDMENT 



Sir: 



ATTACHMENT F 



Serial No.: 08/479,810 



Page 1 of 5 



Docket: YO987-074BZ 



New York and London 



JOURNAL OF SOLID STATE CHEMISTRY 39, 120-127 (1981) 



Oxygen Defect K 2 NiF 4 -Type Oxides: The Compounds 

La 2 _ x Sr x Cu0 4 - x/2+6 



NINH NGUYEN, JACQUES CHOISNET, 1 MAR YVONNE HERVIEU, 
and BERNARD RAVEAU 

Laboratoire de Cristallographie et Chimie du Solide, L.A. 251, ISMRA, 
Universite de Caen, 14032 Caen Cedex, France 

Received December 29, 1980; in final form February 18, 1981 



Oxygen defect K t NiF 4 -type oxides Laj.j.Srj.CuO^xn+j have been synthesized for a wide composition 
range :0 s i s 1.34. From the X-ray and electron diffraction study three domains have been 
characterized: orthorhombic compounds with LajCuO, structure for 0 s x < 0. 10, tetragonal oxides 
similar to LaSrCuO, for 0. 10 s x < I and several superstructures derived from the tetragonal cell (a = 
n fl L»srcua, with n = 3, 4, 4.5, 5, 6) for 1 s x =s 1.34. The compounds corresponding to 0 < x < 1 differ 
from the other oxides in that they are characterized by the presence of copper with two oxidation 
states: +2 and +3. A model structure for Lao. 8 Sr,. 2 CuXOj. 4 , in which copper has only the +2 oxidation 
state, and for which the actual cell is tetragonal — a = 18.80, A and c = 12.94 A— has been established. 
The particular structural evolution of these compounds is discussed in terms of a competition between 
the capability of Cu(II) to be oxidized to Cu(III) and the ordering of oxygen vacancies. 



Introduction 

A lot of oxides, with the A 2 M0 4 formula, 
characterized by the intergrowth of 
perovskite- and sodium chloride-type 
layers are known at the present time. Con- 
trary to the perovskite oxides, no oxygen 
defect has been observed for this structural 
series to our knowledge. Copper, due to its 
ability to take different coordinations 
smaller than six, is a potential candidate 
which could form such anion defect com- 
pounds. However the only isostructural 
copper compounds which have been syn- 
thesized, LagCuO* (1,2) and SrLaCuO, (3) 
are stoichiometric. Nevertheless, the re- 
cent results concerning the oxides 
La^^O^ (A = Ca, Sr) (4), whose 

1 Author to whom reprint requests should be ad- 

0022-4596/81/ 100120-08$02.00/0 i; 
Copyright © 1981 by Academic Press, Inc. 
All rights of reproduction in any form reserved. 



structure is strongly related to that of 
Sr 3 Ti 2 0 7 (5) suggest the possibility of oxy- 
gen defect for A 2 Cu0 4 compounds. Thus, 
the present work deals with the oxides 
La 2 _ J .Sr J .Cu0 4 _ x/ 2+s , for which the replace- 
ment of lanthanum by strontium leads to 
the formation of oxygen vacancies, involv- 
ing order phenomena. 

Experimental 

For the synthesis of the compounds of 
the system LajCuO^S^CuOs, SrC0 3 , CuO 
and La20 3 were mixed according to the 
following ratios: (2 - xf/lL^Oi/x SrC0 3 /l 
CuO. All these reactions were made in a 
platinum crucible in air. The synthesis of 
the compounds with high purity strongly 
depends on the temperature for a fixed 
pressure. The mixtures were thus first 
heated for 5 hr at 900°C, and then at tem- 



peratures ranging 
12 hr. 

The oxidation s 
oxygen defect, was 
the compounds by 
reactions were foil' 
try using a Setarai 

The crystallogn 
lished by two com 
ray diffractometry 
with a Philips goni 
fraction using an 
scope. 

Results 

Study of the Systet 
The Compounds L 
According to the 
scribed, K 2 NiF 4 -t; 
sponding to the 
La^S^Cu^,^ 
large composition r 
microthermogravin 
ides under hydroj 
that a part of Cu(I 



Range 






I 


0 


0 




0.08 


o.o: 


II 


0.25 


0.0 




0.33, 


0.1 




0.50 


0.11 




0.66 6 


o.a 




0.88„ 


0.01 


III 


1.00" 


0.0 




1.28° 


0.0 




1.34" 


0.0 




1.20 


0.0 



° The "a" parameters 
composition are given in 



OXYGEN DEFECT KjNiF 4 -TYPE OXIDES 



121 



l\J, 



hat of ' 
»f oxy- 
Thus, 
oxides 
^place- 
ads to 
nvolv- 



peratures ranging from 1000 to 1200°C for 
12 hr. 

The oxidation state of copper, i.e., the 
oxygen defect, was determined by reducing 
the compounds by hydrogen: the reduction 
reactions were followed by thermogravime- 
try using a Setaram microbalance. 

The crystallographic data were estab- 
lished by two complementary methods: X- 
ray diffractometry using CuA"« radiation 
with a Philips goniometer and electron dif- 
fraction using an EM 200 Philips micro- 
scope. 

Results 

Study of the System La 2 CuO t -Sr 2 CuO a : 
The Compounds La 2 . x Sr x Cu0^ xl2+s 

According to the methods previously de- 
scribed, K 2 NiF 4 -type compounds corre- 
sponding to the nominal composition 
La 2 _ x Sr x Cu n 0 4 _ x/2 were synthesized in a 
large composition range: 0 < x < 1 .34. The 
microthermogravimetric study of these ox- 
ides under hydrogen showed, however, 
that a part of Cu(IT) had been oxidized to 



Cu(III), leading to the formula 
Laj.^Sr^CuO^.^+a with 0 < S < 0. 12. For 
x > 1.34 a mixture of the K 2 NiF 4 -type 
phase and Sr-jCuQ, (6) was observed. 

The crystallographic data of different 
compositions are summarized in Table I. 
The study of the X-ray patterns showed a 
continuous evolution of the structure and 
allowed to characterize three composition 
ranges which were studied by electron dif- 
fraction. 

(/) 0<*<0.10. The X-ray patterns 
very similar to that of LajCuO., (/) were 
indexed in an orthorhombic cell with: 

a x = 2a p sin 0/2 = a^, 

bt = 2a p cos 0/2 = fc U2Cu04 , 

C I ~ c La 2 Cu0 4 > 

where a p is the parameter of the perovskite 
cubic cell, and /3 defines the monoclinic 
distortion of the cell. 

From the conditions limiting possible 
reflections— hkl : h + k, I + h, k + / = In— 
three space groups are possible: Fmmm, 
Fmml, andF222. 



TABLE I 

Crystallographic Data of La i - x Sr x Cu0 4 - J/ j +5 Compounds 



Range 




S 


I 


0 


0 




0.08 


0.030(1) 


II 


0.25 


0.060(4) 




0.33, 


0.119(4) 




0.50 


0.100(4) 




0.66s 


0.092(4) 




0.88, 


0.088(4) 


III 


1.00° 


0.0 




1.28° 


0.0 




1.34- 


0.0 




1.20 


0.0 



Composition 


(A) 


b 

(A) 


(A) 


Heating 
temperature 
CC) 


La,Cu0 4 


5.366(2) 


5.402(2) 


13.149(4) 


1100 


Lai.KSro.ogCuOa.K, 


5.351(1) 


5.368(2) 


13.200(5) 


1000 


LaLreSr.jsCuOs.Mj 


3.775(2) 




13.247(5) 


1000 


Lai.M 1 Sr 0J , J CuO,. 9 5 


3.776(1) 




13.250(2) 


1100 


La1.wSro.soCuO3.s5 


3.773(1) 




13.204(3) 


1160 


La 1J3] Sro.« 6 Cu0 375ll 


3.775(1) 




13.150(4) 


1170 


LamSrcasCuO,.,,, 


3.773(1) 




13.073(5) 


1170 


LaSrCuOjso 


3.767(1) 




13.002(3) 


1200 


LaonSr.jsCuOjjo 


3.761(2) 




12.922(9) 


1200 


Lao^Sr.^CuOs^ 


3.759(3) 




12.907(9) 


1200 


Lao-noSr^CuOj^o 


18.803(7)' 




12.941(7) 


1200 



" The "a" parameters of these compounds (range III) ai 
composition are given in Table II. 



: those of the tetragonal subcell;n values for every 



NGUYEN ET AL. 



goiaMike ^JiSssrSy^ r ty H The el r ron diffraction p atterns al " 

parameters are iSteS^hiti- »ri to ? US , t0 ^ the f °"° win « re,ations 
in the following nSnne * 1 ^ ^ tCtrag ° nal Cel1 for a composition 



= a LaSrCu0 4 » 



a a = cr,/2 1 ' 2 = a p ■■ 

C " ~ C I ~ c LaSrCuO<- 

The reflection conditions are those of 
LaSrCuCV- hkl-.h + k + l= In— involving 
the space groups: IA/mmm, IA/m, I All and 
/42m. 

(///) l£jr< l ; 34. The X-ray diffracto- 
grams are characterized by the existence of 
a system of strong peaks, which was al- 
ready observed for the compounds (II), 
involving at least the existence of a tetra- 
gonal subcell of the same type. However, 
for all these patterns, weak peaks were 
always observed which could not be in- 
dexed in this cell. An electron diffraction 
study was thus undertaken: about 50 crys- 
tals were examined for each value of x 
given in Table II. Several types of crystals 
were isolated: 

— Small number of crystals, about 10%, 
were characterized by a tetragonal cell sim- 
ilar to that of LaSrCuCV 

a m ~ a n ~ a P ~ 



a m - na m ~ na n , 

c fu = c m # c„ = c,. 
For a same composition x, several sorts of 
superstructures were generally observed 
characterized either by integral n values (n 

- 4, 5, or 6) or nonintegral values of n (n 
ranging from 4.5 to 5.6), as shown for 
several compositions in Table II. Figure 1 
shows, as an example, the electron diffrac- 
tion patterns of the (001) planes for 
L^S^aCuOajg. From Table II it can be 
seen that a pure term, characterized by a 
superstructure with an integral value of n (n 

- 5), is only obtained for x = 1.20. It has 
thus been attempted to elaborate a struc- 
tural model for this phase. 



a LaSrCu0 4 > 
- c ! ~ C laSrCu0l . 

—Most of the crystals, i.e., about 90%, 
presented, in addition to the fundamental 
reflections previously described, super- 
structure reflections with a variable inten- 



TABLE II 

n Values Observed by Electron Diffraction 
for Compounds of Range III 



Composition 



LaSrCu0 3 . 5 
Lao-esSlVuCllOa M 
La«.<»Sr 1J!0 CuO 340 
Lao-nSr^co,^ 



I; 4.5 
1; 4.5; 5 



1; 4.6; 5; 5.3; 5.4 
1; 4; 5; 5.6; 6 



A Structural Model for La 0 . s Sr 1J2 CuO 3A 

The actual cell of this compound is tetra- 
gonal: a = I8.80 4 A and c = 12.94 A (Z = 
50). The conditions limiting possible 
reflections are the same as those of the 
subcell (a = 3.760, c = 12.94 A; Z = 2) 
leading to the space groups IA/mmm, 
I A/m, I All, and /42m. The intensity calcu- 
lations were first made in the K 2 NiF 4 type 
cell, with the most symmetric space group 
IA/mmm. For these calculations, 
reflections corresponding only to the 
subcell were used. Copper atoms were 
placed on 2(a), lanthanum and strontium 
atoms were statistically distributed on Ae, 
and oxygen atoms and anionic vacancies' 
were statistically distributed over two sorts 
of sites Ae (O,) and Ac (O n ). After 
refinement of the atomic parameters the 
discrepancy factor could not be lowered 
below R = 0.104. The possibility of an 
order of the oxygen atoms and vacancies 
over the O, and O n sites was thus consid- 
ered. The occupancy factors of both sites 





Sites 














La} 
Sri 


4(<0 


0 


0 


Cu 


2(a) 


0 


0 


0, 


4(e) 


0 


0 


o„ 


4(c) 


0 


0,5 




= 3.760 A; 




12.94 



OXYGEN DEFECT K 2 NiF«-TYPE OXIDES 



erns al- 
ions for 
position 



sorts of 
served, 
dues (n 

Of/7 (#1 

wn for 
'igure 1 
diffrac- 
ies for 
can be 
sd by a 
• of n {n 
. It has 
i struc- 



O3.4 
s tetra- 
k(Z = 
ossible 
of the 
- = 2), 
Immm, 
■ calcu- 
type 
5 group 
ations, 
o the 
; were 
Dntium 




Fig. 1. Electron diffraction patterns of the (001) planes for La^-Sr^CiiO 
(d) 6. '- 3 53 



(a)n = l:(b)4:(c)5.6: 



were refined successively and then simulta- 
neously and the best value of R = 0.081 
(Table IV) was obtained for a total occupa- 

TABLE III 

^.soSrLjoOa.^: Atom Positions in the Subcell" 



Sites 




y z 


(A*) 


Lai 

Sr] 


4(e) 


0 


0 0.357 ± 0.001 


0.88 


Cu 


2(a) 


0 


0 0 


0.85 


0, 


4(e) 


0 


0 0. 168 ± 0.002 


1.68 


o„ 


4(c) 


0 


0,5 0 


4.25 




= 3.760 A 




12.94 A. 





tion of the O, sites, while vacancies and 
oxygen atoms were distributed over the O n 
sites. The location of the vacancies prefer- 
entially on the O u sites, at the same level as 
the copper atoms, can be considered as 
significant, on account of the relatively 
weak scattering factor of oxygen. This is 
confirmed by the high R value (R = 0. 153) 
obtained for a total occupation of the 0„ 
sites, vacancies and oxygen atoms being 
distributed on the O, sites. The first results 
which are summarized in Table III show 
the atoms are located in positions very 
close to those usually observed in K 2 NiF 4 
type structures. The main difference with 



124 



NGUYEN ET AL. 



TABLE IV 
LaojSr.jCuOa.^: Observed and 
Calculated Intensities for Atomic 
Positions of Table III" 



hk 1 


/ obI 


rale 


00 2 


4.0 


4 0 


1 0 1 


13.0 


15 1 


00 4 


17.0 


16 9 


1 0 3 


164.0 


156 1 


1 1 0 


114.0 


IIS 1 


112 






00 6 


29.0 




1 0 5 


27.0 


23 5 


1 1 4 






20 0 


44.0 


49 8 


20 2 


0.1 


0.4 


J! 3 


26.0 


25.2 




3.9 


3.8 


1 0 7 


12.0 


11.1 


2 0 4] 


10.3 


8.2 


0 0 8J 


6.6 


5.3 


213 


48.0 


48.1 


2 0 6] 


15.8 


18.1 


2 1 5/ 


8.1 


9.4 


1 1 8 


9.0 


7.5 


1 0 9 


0.1 


1.7 


22 0 


9.0 


12.4 


22 2 


0.1 


0.1 


0 0 10 


0.1 


0.8 


30 1 


0.1 


0.7 


2 1 7 


6.0 


7.0 


2 2 4} 


3.3 


3.0 


2 0 8/ 


7.6 


6.9 


30 3 


7.0 


8.8 


° Subcell, space group /4/mn 


nm;R = 



0.081. 



the ideal structure concerns the existence 
of vacancies located in the same plane as 
the copper atoms (Fig. 2). Moreover, the 
high B value for oxygen of O, sites (4.2 A 2 ) 
suggests that in this plane oxygen and va- 
cancies were ordered. 

Calculations in the actual cell in space 
group 1 4/ mm, were undertaken with 136 
possible reflections, including superstruc- 
ture reflections. Using the position and 
distributions determined from the subcell, 
the R factor increased to 0. 104, showing, of 
course, a weak contribution of the super- 
structure reflections to the R value. The 




Fig. 2. Ideal drawing of the tetragonal KjNiF^type 
structure showing the localization of oxygen vacancies 
forLa 0 . e Sr 1 .iCuO, < . 



atomic parameters were then refined and 
the R value was lowered to 0.07 for the final 
atomic parameters given in Table V. From 
this table it can be seen that copper atoms 
are not significantly displaced from their 
ideal positions, while the bigger cations La, 
Sr, and the oxygen atoms are only slightly 
displaced from their ideal positions, but 
enough to produce the superstructure 
reflections. These small displacements are 
certainly induced by an order of the oxygen 
vacancies, whose contribution to intensi- 
ties is too small to be detected here. Thus, 
on account of the numerous possibilities of 
order between vacancies, and oxygen 
atoms, and of the weak scattering power of 
these atoms, we did not try any hypothesis 
of distribution. Nevertheless, the very 
likely ordering of vacancies in the "copper 
plane," should also involve an ordering of 
lanthanum and strontium over the different 
sites. Refining the occupancy factors of La 
and Sr, led to an R value of 0.064 which is 
not very significant due to the weak contri- 
bution of La and Sr to the superstructure 
reflexions; a preferential occupation of the 
different sites is, however, likely: A ly A 4 , 
and A s would only be occupied by stron- 
tium, while lanthanum would occupy 90% 
of A 6 sites, the remaining strontium and 
lanthanum atoms being located statistically 
over the A 2 and A a sites. 



Lao sSr.^SuO,.,: Ai 
Aa 





x 


i4,(4c) 










n Atrt 


A t (\bm) 






n 'a 
0.410 


/M32f« 


0.389 


A (2d) 




. A»m 


0.200 


A,(Si) 


0.400 


A W (8A) 


0.200 


A„(Sh) 


0.405 


A U (I6/) 


0.403 




0 


A tt (l6n) 


0.216 


A ls (l6n) 


0.382 


A u (l(>m) 


0.182 


A„V(>m) 


0.400 


A 16 (320) 


0.400 




0.100 


A„m 


0.300 


A„(4c) 


0 


A„(i6l) 


0.214 


A„(lbl) 


0.430 


A„(\6l) 


0.300 


A a (lbl) 


0.390 


A„m 


0.200 




0.400 



° a = 18.804 A; c = 
j IJmmm). 




i Cu(in) by only heati 
worthy of note. Bui 
characteristic of this 
existence of a Cu(III) 
< x < I) which lies 
regions (x = 0 and a 
strongly related one t 
j be explained by two c 
i are competitive: the 
stoichiometric K 2 NiI 
La 2 Cu0 4 and LaSrCi 
form a related defect ! 



OXYGEN DEFECT KjNiF^TYPE OXIDES 



125 



TABLE V 

Laa.jSiY.SuOs.,: Atomic Parameters of ti 
Actual Cell" 



:d and 
le final 
From 
atoms 
1 their 
<ns La, 
;lightly 
is, but 
ucture 
nts are 
oxygen 
ntensi- 
. Thus, 
ities of 
Dxygen 
>wer of 
othesis 
; very 
copper 
;ring of 
ifferent 
s of La 
/hich is 
contri- 
ructure 
i of the 
A lt A 4 , 



Sites 








(A 1 ) 


A,(4e) 


0 


0 


0.347 


0 35 


A,(\bn) 


0.194 


0 


0.359 


1 00 


A 3 (l6/i) 


0.403 


0 


0.356 


0 39 


A t (\bm) 


0.200 


0.200 




0 32 


A 5 (l6m) 


0.410 


0.410 


0 358 


1 00 


A«(320) 


0.389 


0.192 


0 357 


0 86 


A 7 (2a) 


0 






0 80 


A,(80 


0.200 








A,(8/) 




0 




0 43 


A,.(8A) 


0.200 


0.200 


0 


0.31 


A„(8A) 


0.405 


0.405 


0 


1.00 


A U (IW) 


0.403 


0.205 


0 


0.37 


A a (4e) 


0 


0 


0.168 


1.00 


A 14 (l6n) 


0.216 


0 


0.168 


1.00 


A ls (16n) 


0.382 


0 


0.168 


1.00 


A,„(l6ni) 


0.182 


0.182 


0.172 


1.00 


A 1T (l6/n) 


0.400 


0.400 


0.168 


1.00 


A 18 (320) 


0.400 


0.202 


0.163 


1.00 


A,.(80 


0.100 


0 


0 


1.00 


A„(8«l 


0.300 


0 


0 


1.00 


A„(4c) 


0 


0.500 


0 


1.00 


A B (I6/) 


0.214 


0.100 


0 


1.00 


A a (\(,l) 


0.430 


0.100 


0 


1.00 


A U (\(J) 


0.300 


0.200 


0 


1.00 


A„(16/) 


0.390 


0.310 


0 


1.00 




0.200 


0.500 


0 


1.00 




0.400 


0.500 


0 


1.00 


° a = 18.804 
IJmmm). 


A; c 


= 12.941 


A (space 


group 



The stabilization, in this system, of 
Cu(ni) by only heating the oxides in air is 
worthy of note. But the most important 
characteristic of this system concerns the 
existence of a Cu(III) composition range (0 
< x < I) which lies between two Cu(II) 
regions (x = 0 and x > I), for structures 
strongly related one to the other. This can 
be explained by two opposite effects which 
are competitive: the trend to preserve a 
stoichiometric K 2 NiF 4 structure as for 
La 2 Cu0 4 and LaSrCu0 4 and the trend to 
form a related defect structure but with an 



ordering of the oxygen vacancies. Thus, 
rather close to the stoichiometric com- 
pound La2Cu0 4 (jr < I), the trend to stoi- 
chiometry is favored and the vacancies 
formed from the nominal compositions in- 
volving only Cu(II) are partly balanced by 
the oxidation of Cu(II) to Cu III. For x > | , 
i.e., rather far from stoichiometry, the 
La 2 Cu0 4 or "LaSrCu0 4 " stoichiometric 
compounds cannot be stabilized any more 
and orderings of the oxygen vacancies ap- 
pear leading to different microphases as 
observed from the electron diffraction 
study, favoring Cu(II) with smaller coordi- 
nations (2, 5). 

Structure is not, of course, the only fac- 
tor governing the relative stability of Cu(II) 
and Cu(III) in these oxides. Kinetics play 
an important part for determining the ratio 
Cu(III)/Cu(ID in the richer Cu(III) oxides. 
For 0 < x < I , we have indeed noticed that 
the pure compounds could only be synthe- 
sized by heating at least 12 hr at the forma- 
tion temperature (Table I) in order to en- 
sure a good crystallization. Annealing the 
same samples at the same temperature, 
during longer periods (24 hr) allows us to 
prepare pure phases with the same struc- 
ture, but with greater amount of Cu(III). 
The oxygen pressure will also influence the 
Cu(III)/Cu(n) ratios. Heating, for exam- 
ple, some Cu(III) samples at low tempera- 
ture under vacuum, involves a decrease of 
Cu(III) amount without destroying the 
structure. In the same way, a reaction 
under oxygen allows us to increase the 
Cu(III) amount. 

The influence of the Cu(III) amount can 
also be detected by considering the struc- 
tural evolution, especially the c parameter, 
of these compounds as a function of com- 
position (Fig. 3). This evolution is rather 
complex and quite different from that usu- 
ally observed for single solid solutions. The 
substitution of strontium for lanthanum, 
should not affect this evolution, due to the 
similar sizes of these cations. It seems 
interesting to take the Cu(II) compounds as 



NGUYEN ET AL. 




a reference (dotted lines). Although we 
have only our compositions for comparison 
it can be seen that from LajCu 1 ^ to 
La 0 .7Sr 1 .3Cu II O 3 ^5 , a continuous decrease of 
a and c parameters could be foreseen for all 
Cu(II) compounds, as x increases, in agree- 
ment with the increase of oxygen vacan- 
cies. This evolution is not linear, probably 
due to ordering of the vacancies observed 
for different compositions. What is worthy 
of note is the large deviation from this law 
observed for the only compounds contain- 
ing Cu(III) (continuous line): the c parame- 
ter is greater than that obtained from the 
"reference line" corresponding to the pres- 
ence of Cu(II) only, while the a parameter 
is smaller. Moreover, the largest devia- 
tions are observed for x = 0.33 which 
corresponds to the maximum value of 8 (8 
= 0.119), i.e., for the greatest amount of 
Cu(III). It can thus be observed that the c/ a 



ratio increases with the Cu(III)/Cu(II) ratio 
in agreement with the observations previ- 
ously made by Goodenough et al. (3). At- 
tempts to modify the a and c parameters for 
x = 0.16 and 0.5, were successful: heating 
these compounds under vacuum at 500°C 
led to a decrease of c and a slight increase 
of a , while a decrease of the Cu(III)/Cu(II) 
ratio was confirmed. 

Conclusion 

The stabilization of a great number of 
oxygen vacancies in the K 2 NiF 4 -type struc- 
ture has been shown. It is easily explained 
by the ability of copper to show square and 
square-pyramidal coordinations. During 
the synthesis in air, two phenomena are 
competitive: the substitution of Cu 3+ for 
Cu z+ , and ordering of oxygen and vacancies 
involving the existence of microphases. 



OXYGEN DEFECT K 2 NiF 4 -TYPE OXIDES 



127 



The influence of the oxygen pressure on the 
formation of these structures will be inves- 
tigated. The relations between the electrical 
properties and the structure of these oxides 
will be studied. 



References 

/. J. M. Longo and P. M. Raccah, J. Solid State 
Chem. 6, 526(1973). 



2. B. Grande, H. K. MOller-Buschbaum, and M 
Schweizer, Z. Anorg. Allg. Chem. 428, 120 
(1977). 

J. B. Goodenough, G. Demazeau, M. Pou- 
chard, and P. Hagenmuller, J. Solid State 
Chem. 8, 325 (1973). 

4. N. Nguyen, L. Er-Rakho, C. Michel, J. 
Choisnet, and B. Raveau. Mater. Res. Bull 15, 
891 (1980). 

5. S. N. Ruddlesden and P. Popper, Acta Crystal- 
logr. II, 54(1958). 

6. C. H. R. L. Teske and H. K. Muller-Busch- 
baum, Z. Anorg. Allg. Chem. 371, 325 (1969). 



BRIEF ATTACHMENT G 



IN THE UNITED STATES PATENT AND TRADEMARK OFFICE 



In re Patent Application of 
Applicants: Bednorz et al. 
Serial No.: 08/479,810 
Filed: June 7, 1995 



Group Art Unit: 1751 
Examiner: M. Kopec 



Date: March 1, 2005 
Docket: YO987-074BZ 



For NEW SUPERCONDUCTIVE COMPOUNDS HAVING HIGH TRANSITION 
TEMPERATURE, METHODS FOR THEIR USE AND PREPARATION 



Commissioner for Patents 

P.O. Box 1450 

Alexandria, VA 22313-1450 



In response to the Office Action dated July 28, 2004, please consider the 
following: 



FIRST SUPPLEMENTAL AMENDMENT 



Sir: 



ATTACHMENT G 



Serial No.: 08/479,810 



Page 1 of 5 



Docket: YO987-074BZ 



Mat, Res. Bull., Vol. 20. pp. 667-671, 1885. Printed in the DSA. 
0025-5408/85 $3.00 + .00 Copyright (c) 1985 Pregamon Press Ltd. 



THE 0X5 GEN DEFECT PEROVSKITE BaLa.Cu,0.- ., A METALLIC (XWDOGTOB 



C. Michel, L. Er-Kakho and 8. Raveau 
laboratoire de Cristallographie, Chimie et Physique des Solides, O.A. 251 
ISHBa-Dniversite de Caen, 14032 Caen Cedex, France 



(Received March 14, 1985; Befereed) 



A new oxygen defect pcrovskite BaLa^C^O^.^, characterized by a mixed 
valence of copper has been isolated ; the parauetere of the tetrajtpoal 
cell are closely related to that of the cubic perovskite:a » 8.644(4) I 
= a_ /5 and c - 3.867(3) X « Bp. The X-ray diffraction study shows 
that the atoms are displaced from their ideal positions in the cubic 
cell, owing to the presence of ordered oxygen vacancies. The s tody of 
conductivity, magnetic susceptibility and thermoelectric power versus 
temperature snows that this oxide is a very good metallic conductor. 



IBTRPB0CTIOK 

Oxygen defect perovskltes, have been note extensively studied these 
last years owing to their potential applications ia catalysis, eiectrocata- 
lysls or as gauges (1-3). In this respect mixed valence copper oxides offer 
a wide field for investigation : several perovskltes (4) or perovskite-rela- 
ted structures have been isolated (5-6). These materials in which copper 
takes several coordinations simultaneously and a valence state intermediate 
betwee n II and III can intercalate large amounts of oxygen according to the 
oxygen pressure and the tenser* tare. Their electron transport properties 
ranging from semi-conductive to metallic (7) are closely correlated to the 
amount of intercalated oxygen. 

The present paper deals with a new oxygen defect perovsfcite 
SaLa^CujOiw, which is like M^a^s°U*6 <*> » valence copper oxide 

but whose behavior is quite different. 

gPERIHEHTAL 

Synthesis 

Samples were prepared in platinum crucible and in. air from appropriate 
mixtures <>i dried oxides LagO^, CuO and carbonate BaC0 3 . The mixtures were 
first heated a few hours at 9O0*C, ground and heated at 1000 'C during several 
hours. They were then ground again, and mixed with an organic binder, com- 
pressed lnto^bars and then slowly heated up to lOOO'C. After 24 hours or 
•ore at 1000'C, the bars were finally quenched to room temperature, The use 
of a binder was necessary to avoid that the compressed bars break before 
667 




668 C. MICHEL, et al. Vol. 20. No. 6 

beating. In these conditions the compactness of bars was of about 80 X. 
Chemical analysis 

In order to determine the oxidation state of the transition metal iocs, 
chemical analysis were, carried oat by iodoaetric titration using KI and by re- 
duction in a f low of 25 Z hydrogen in argon up to about. 100Q*C using a SETAHAM 
»ficrobalance for weight loss measurements. 
Structural analysis 

The cell parameters were determined from X-ray powder dif f ractogramms 
. registered with a Philips goniometer using Cu 1^ radiation. The space group 
was determined by electron diffraction using a JEOL I20CX electron microscope. 
Magnetic and electrical measurements 



the conductivity was measured by the four points method on sintered bars. 
It was calculated by measuring the intensity/voltage ratio between the points 
in each current circulation direction in order to minimise the dissyaetry ef- 
fect between the contacts. The Seebeck coefficient was measured on the same 
sintered bars hold between two Pt beads. 

Measurements were carried oat np to 600K under an helium pressure of 
200 lobars for T < 290K and in air for T > 290SC in order to avoid possible de- 
parture of oxygen. 

RESULTS AND DISCUSSES 
The scanning of the system La^y-BaO-CuO for the compositions correspon- 
ding to the molar ratio (La + Ba)/Cu - I allowed us to isolate a perovskite 
for La/Ba •» 4. The X-ray diffraction pattern of this compounds presents be- 
sides the intense lines which can he indexed in a cubic perovskite cell, extra 
lines which axe rather weak. lhis : feature is confirmed by the elect rem dif- 
fraction study, which shows super structure reflection's, leading, to a tetra- 
gonal cell whose parameters are related to the cubic perovskite subcell (a ) 
as follows i P 

all the lines of the X-ray diffraction patterns can be then 
indexed with accuracy In the tetragonal system with a - 8,644(4) A and c - 
3.867(3) A. So reflection conditions are observed. The analysis of the oxy- 
gen content leads to the formulation BaLa^O^O^.^ involving the presence 
simultaneously of Cu(II) and Cu(IIl) in spite of "the presence of numerous oxy- 
gen vacancies <10;7 X). The measure of the density by pyenoaetry in benzene 
at 25°c(a e xo " '"05) confirms this composition for one mole per cell (d. 
7.63). -^-s - -- - »« v< 



were 

buci 
stud 
posi 

king 

Fhkl 
anglf 

idea] 
of tl 
8 - ! ■ 
BiO) 

ties 
(Tabl 
from 
oxyge 

tfl 



! it appears that the oxide . Bal^Cu 1 ** 2Cu m 2 g0i 3 4 , 6 exhibits 
& great similarity with the oxygen defect perovskite Ba 3 l*,Ctt"« jiCu 111 .^,,©,/. 
previously described. However, this compound is very dlffeTeat^roo 
**f*lpHPn*$. froa tte Point <»f view of the oxygen intercalation t no inters 
calatioo or desinttircalation of oxygen nas been observed fey annealing this pha-> 
se at low temperature (40O*« to 500*C> and under different oxygen pressures op 
to 1 bar contrary to BajIj^&^Oj^. In the same way, no oxygen loss has been 
observed hy TGa measurements for temperatures up to 650; 750 and 850*C and 
under oxygen pressure* of 0.02 ; 0.2 and 1 bar respectively. 

Taking into account the fact that che fundamental lines are indexed in s 
cubic perovskite cell and are strong with respect to the superstructure lines 
it was interesting to determine whether the metallic atoms were displaced 
from their ideal positions in the perovskite, or if the superstructure lines 



in thi 
rather 

1.6 lc 
P v 
tj fro 




J. 20, No. e 
80 X. 



metal ions, 
I and by re- 
ag a SKTABAK 



ctograau 
pace group 
microscope. 



intered bar*, 
the points 
sy iu ett y ef- 



s correepoa- 
erovskite 
esents be- 
cell, extra 
. cCron dif- 

bceli (a) 



\ /exhibit* 

i no incex- 
Ing this pte" 
preasures op 



indexed in * 
cture lines 
displaced 



*c». 20, No. 6 BaLa 4 Cu^0 13 4 669 

cere only due to the ordering of oxygen vacancies. However, owing to the 
foall anoint of oxygen vacancies it was not likely to determine the distri- 
bution of the oxygen atoms by X-ray powder diffraction. Thus the structural 
t toiy was undertaken for the composition la^BaCu^,; just to determine the 
positions of the atoms vita respect to the cubic perovskite sobcell. Eight 
space groups were possible, they were reduced to three F4, M and P4/ai ta- 
king into account the analogy with the perovskite s croc tare. Calculations 
sere carried out in the most symmetrical space group P4/m. For a ranging 
fron 0 to 48", 37 peaks i.e. 84 hkl were registered. The disparity between 
tftfci and F hkl led us to introduce 139 hkl in the calculations. In the sane 
angle r nge 13 diffraction peaks (14 hkl) were indexed in the cubic perovski- 
te cell with a - 3.867 A, and used in a calculation with the atom: in the 
ideal positions of the cubic perovskite cell, involving only a refinement 
of the thermal factors B ; this first refinement led to a discrepancy f fee tor, _ 
8. - E|l obs - I calc|/£ I obs. of O.066 with B(La, Ba) - 1.2 A 2 , 8(Cu) » 2.6A 2 
B(0) - 3.9 A 2 . Hie high B values let ns think that the atoms were displaced 
from their ideal positions. A calculation carried out with all the intensi- 
ties in the M/m space group and rite same ideal positions and overall B - J A 
{fable la), led to S - 0.35 in agreement with this point of view. Starting 
from these ideal positions, and assuming a statistical distribution of the 
oxygen vacancies in the oxides BaLa 4 Cu 5 0| 3 4, the R factor was lowered to 
0.083, by refinement of the atomic parameters , the B factor being fixe at 
1 I*. From the final atomic parameters (Table Kb) it can be seen that se- 
veral atoms are displaced fron their ideal positions in the cubic perovskite. 



Atom 


Site 


X 


(a) 

V. 


Z 


X 


(h) 

Y 


Z 


Ba , La 


Hd) 


o.s 


O.S 


0.5 


0.5 


0.5 


0;5 


Ba, La 


«k) 


0.1 


0.3 


O.S 


0.124(1) 


0.277(1) 


O.S 


0a 


Ka) 


0.0 


6.0 


0.0 


0.0 


0.0 


O.O 


Cu 


*(j) 


0.4 


0.2 


0.0 


0.415(3) 


0.168(2) 


0.0 


0 


1(h) 


0.0 


0.0 


O.S 


0.0 


O.O 


0.5 


0 


2(e) 


0.0 


0.5 


0.0 


O.O 


0.5 


•O.O 


0 


Hi) 


0.3 


0,4 


0.0 


0.261(7) 


0.384(8) 


0.0 


0 


4(j) 


0.2 


0.1 


0.0 


0.229(8) 


0.063(6) 


0.6 


0 


4(k) 


0.4 


0.2 


0.5 


0.428(10) 


0. 155(6) 


o.s 



Further refinements, concerning the ordered distribution of oxygen 
in this structure, which is most probable, were not carried out due to the 
wither low content of oxygen vacancies, and the too small number of refle- 
ctions. 

, This °*ide is a very good conductor s Its conductivity is about 
1.6 lo (C cm)-' at rooa temperature. Figure 1 which represents 'the resistivi- 
ty 0 versus temperature, sho«3 that this oxide exhibits a metallic conductivi- 
ty from 200 to 600K. The y value deduced from the equation p « p 0 (l+Yt) 
r -4.1 10 3 c - ') is very close to that of free electrons (7 - 3.7 10 -3 C -1 ) . 
The molar magnetic susceptibility is very weak and nearly independent 
temperature, this suggests a Paul! paramagnetism which is characteris- 



BRIEF ATTACHMENT H 



IN THE UNITED STATES PATENT AND TRADEMARK OFFICE 



In re Patent Application of 
Applicants: Bednorz et al. 
Serial No.: 08/479,810 
Filed: June 7, 1995 



Date: March 1, 2005 



Docket: YO987-074BZ 



Group Art Unit: 1751 
Examiner: M. Kopec 



For NEW SUPERCONDUCTIVE COMPOUNDS HAVING HIGH TRANSITION 
TEMPERATURE, METHODS FOR THEIR USE AND PREPARATION 



Commissioner for Patents 
P.O. Box 1450 
Alexandria, VA 22313-1450 



In response to the Office Action dated July 28, 2004, please consider the 
following: 



FIRST SUPPLEMENTAL AMENDMENT 



Sir: 



ATTACHMENT H 



Serial No.: 08/479,810 



Page 1 of 5 



Docket: YO987-074BZ 



L8. Z'. S3J 





g cS |j 



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9m 111 f Iff III 

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3 3 

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l*J2i 

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iS § « '§> « 
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fif^ifi ill 



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§.i si 



a -» ° 5 6 I 2 .a 3 v *. 



fiilfpflli 

IlllllJlll] 



0Td Wd82:£8 £002 21 -q3j 



&LZ6 96S T0C 



BRIEF ATTACHMENT I 





IN THE UNITED STATES PATENT AND TRADEMARK OFFICE 



In re Patent Application of 
Applicants: Bednorzetal. 
Serial No.: 08/479,810 
Filed: June 7, 1995 



Group Art Unit: 1751 
Examiner: M. Kopec 



Docket: YO987-074BZ 



Date: March 1, 2005 



For. NEW SUPERCONDUCTIVE COMPOUNDS HAVING HIGH TRANSITION 
TEMPERATURE, METHODS FOR THEIR USE AND PREPARATION 



Commissioner for Patents 
P.O. Box 1450 
Alexandria, VA 22313-1450 



In response to the Office Action dated July 28, 2004, please consider the 
following: 



FIRST SUPPLEMENTAL AMENDMENT 



Sir: 



ATTACHMENT I 



Serial No.: 08/479,810 



Page 1 of 5 



Docket: YO987-074BZ 



lK^jjggHtt«5T0N_^^ SUC. PHONE NO. ; 381 595 q??g 



Feb. 17 2005 65:01Pfl PA 



CIP-Kuraiiclaufn«hmc dcr Dcutschcn 



Thermal analysis. - Basel, Boston, Siangan: 
Birkhauscr. 

B<J. 1971 nit d. Encheuiungsoncn: Basel, 
Stuttgart - Ed. 1977 im Vat Heyden. Lon- 
don. BeUnunwr (NJ), Rhcmc. 
ISBN 3-7643- 1202-5 
1980. 

Vol 2. Inorganic chemistiy, metallurgy, 



All rights reserved. No pari of thin publica- 
tion may be reproduced, stored m a 



earth iciertces, organic charm try, polymers, retrieval system, or transmitted in any form 



biological sciences, medicine, pharmacy: 
proceedings of the 6. Internet Conference 
on Thermal Analysts, Bayreuth, Fed. 
Republic of Germany, July 6-12, 1980/cd. 
W. Hcouningcr. - 19R0. 
ISBN 3-7SO-1066-3 © Birkhiuscr Vertag Bawl. I9S0 

WE: Hcxnmiagcr, Wolfgang (Hrtg J: ICTA ISBN 3-7643-1086-3 
<06, mo. Baymittu Printed in Switzerland 



or by any means, electronic, mechanical, 
photocopying, recording or otherwise, with- 
out the prior permission of the copyright 
owner. 



Although the use o 
sions began in the i 
of the effects of he$ 
20ib century. In 0 
broadly applicable 
Forademonstratio 
volume. From acad 
quality control of h 
tools for the socnti 
field of endeavour, 
others employ then 
and chemical proa 
Growth in the" valu 
ing number of nati 
common ground ai 
application of ties 
a similar but broad 
ing an opportunitj 
common interests ; 
of experts continue 
turc, standards an 
together ICTA an< 
to work, to find st: 
analysis. The end i 

Onta 
Miss 



FEB 17 2005 14=26 
0T/f0"d 



NK1D6J0A 01 9if T662C0i 



301 595 9279 PAGE. 04 

biyaNyxany-wai yd pq-.pi 2002 lx trad 



Feb. 17 2805 B5:01Prt ps 



THERMAL BEHAVIOUR OF COMPOSITIONS TN THE SYSTEMS 
x BaTio 3 ♦ <l-x) ^^no.sBo.s'Oj 

V.S. Chincholkar" and A.R. vyawahare 
Department of Chemistry, Institute of Science, Nagpur 

ABSTRACT 

The effect of temperature on the dielectric constant (£) . 
tan 6 (loss tangent) and the ferroelectric properties of 
compositions in the systems x BaTiO^ ♦ (1-x) Ba (Ln 0 5 B fl g Jo 3 
(0«x«i, Ln 3 * o a rare earth cation and r 3 *, B 5 * = Ta.Nb.v) 
reveal that in the Ta S * system at x = 0.8, the £ ^ (£ at 
T c ) and T Q (the Curie-point) exhibit an increasing trend 
with decreasing ionic radii of the Xn 3 * ions, whereas in 
the analogous sb 5 * system, an almost linear behaviour has 
been observed. In the v 5 * system, the pure phases (x = 0) 
exhibit increasing trend of and T c values with de- 

creasing rare earth cation size. Phases with x = 0.8, exhibit 
a break at Nd 3 * in values, in contrast to an increasing 

trend in T c values with decreasing rare earth cation size. 
Similar behaviour is observed for the polarization, data. The 
increasing trend in the T c values in the direction Ta 5 *-Nb 5+ - 
V 5 * at x = 0.8 is perhaps reminiscent of the nephelauxetic 
effect. 

The T c values for these first order transitions have been 
confirmed by recording DTA curves against inert a-Al 2 0 3 , the 
enthalpy change, however, being appreciably low in the pre- 
sent series. 



INTRODOCTION 

Recently emphasis has been placed on laser research and a 
concentrated effort has brought new and improved materials 
which can be used as hosts for transition. An important part 
of this effort has been directed towards finding potential 
laser materials having fluorescent energy states with long 
life times. In order to determine, if symmetry conditions in 
THCRmU. ANALYSIS . ICTft 60 . 8IRKHACUSEA VCTUC.BASEL , BOSTON. STUTTCART 



FEB 17 2085 14:26 
BVSB'd 



NHQiXIQA 01 9<LfrT662£0<L 



301 595 9279 PAGE. 05 

yiyaNUxanb-wai ad vsipi 2002 l\ a3d 



252 



crystals also affect the life time of rare earth ion fluores- 
cence, a series of ordered perovsklte compounds having the 
general formula M B o.5 B o.s )0 3 were studied HJ-C7J. However, 
temperature effects ana doping characteristics were not stu- 
died. The present work concerns with the formation and the 
thermal characteristics of compositions in the systems 
x BaTio 3 * (l-x) Ba(Ln 0 5 B 0 5 >o 3 where 0<S 1 , tj\ 3 * « a rare 
earth cation and Y. 0 s * = ub^*, Ta^* and V 5 *. 

EXPERIMENTAL PROCEDURE 
The compositions were prepared by the solid state reaction 
of the parent compounds (carbonates, oxides) at high tempera- 
ture as described elsewhere 18], [9]. Room temperature X-ray 
structure was determined using Debye-Scherrer camera (14 cm 
diameter) and nickel-filtered Cu-I^ radiation. Temperature 
effects on the dielectric constant (capacitance) and loss 
tangent (tan 6) were measured using a 716-C OB capacitance 
bridge together with type 1340-B type audiobeat frequency 
generator and 1231-8 type u null detector and amplifier with 
1231 ? 5 ty P e variable filter in a sample holder designed in 
this laboratory [10 J. 

Modified [11 J Sawyer-Tower type circuit was used to record 
hysteresis loops as a function of temperature in the above 
sample holder and a MOK Derivatograph was used to record DTA 
curves against a-Al 2 0 3 as reference. 

RESULTS AND DISCUSSION 
Tables 1-3 show the room temperature £ values as also the 
£ max and the Curie-point (T e > values evaluated from the capa- 
citance measurements for compositions in the various systems. 
The temperature^study e was restricted to x «= 0.8 compositions 
in the Ta *, Nb + systems and over the entire composition 
range in the V S * system which exhibited the transition in the 
whole range of compositions. Table 4 shows these parameters 
at x = 0 for compositions ia the V 5 * system, xn all the sy- 



stems, an increasin 
with decreasing rar 
scent of the lantha 



Ba(La Q _ 


Ta 0.1 Ti 0.8 : 


Ba(Nd 0 


i Ta o.i Tl o.a 


Ba(Sm 0 _ 


1 Ta 0.1 Ti 0.B 


Ba(Gd 0 


i Ta o.i Ti o.e 


BalOy 0 


1 Ta 0.1 Tt 0.B 


^O.I^O.l'W 


€ max' * 


s and T c ve 


Ba(La 0 


1 Nb 0.1 Ti 0.l 


Ba(»d 0 _ 


1 Bb 0.1 T1 0.i 


Ba(S» 0 


1*0. 1«0.» 


Ba(Gd 0 


I^O.l'V 


Ba{Dy 0 " 


1* b 0.1«0.. 


^O.l 


^O.l^O.S 


* , P 
max' 


s and T e v 




1 V 0.1 Tl 0.8 


Ba(Nd ft 


lVl T1 0.B 


B&(Sm„ 


i v o.i Ti p.e 


Ba«Sd 0 ' 


1 V 0.n Ti 0.£ 


Ba(Dy 0 


1 V 0.1 T1 0.£ 



'o.ro.i^o.-B' 



2^£L£i£H°ggggM^SUC. PHONE NO. : 3B1 595 9?7g 



Feb^l7 2005 es:B2Pi>r P7 



ray 



with decreasing rare earth cation size, and is perhaps remini- 
scent o£ the lanthanide contraction. 



V and T values for compositions in the t& system 



Composition 


Ss-c 


? « 2 


£ max 


T c 






Uc/om 2 ) 




fci 


Ba(La o.i Ta o.i Ti o.a>°3 


200 


4.5 


780 


85 


Ba(Nd 0.l Ta 0.1 Ti 0.8 )0 3 


250 


6.0 


850 


90 


fiats Vi Ta o.i T1 o.a )0 3 


342 


8.1 


1050 


92 


BalGd 0.1 Ta 0.1 Ti 0.8>°3 


480 


8.5 


1120 


96 


Ba(Dy 0 ,Ta 0 ^i 0 8 )O 3 


530 


8.9 


1400 


100 




580 


9.6 


1830 


110 




Table 


2 






^nax' P s and T c val - ue9 for compositions in 


the systems Mb * 


!a,L4 0.1 ,ft 0.1 Ii 0.! ,O 3 


232 


5.3 


S80 


90 


Ba(Nd 0.1 Nb 0.1 Ti 0.8 ,O 3 


250 


6.2 


900 


100 


BalSw O.1 Mb O. 1 ' ri O.0 ,O 3 


290 


8.4 


1100 


107 


8 * (Gd 0.1 Mb 0.1 Ti 0.8 ,O 3 


380 


9.2 


1220 


110 


" , ^fl.l" b 0.1 ,i l.8 ,O 3 


415 


9.8 


1350 


115 




530 


10.2 


1600 


118 





Ba(La 0.l V o 


i Ti o.e )0 3 


170 


4.5 


1100 


93 


apa- 


Ba(l,d 0.1 V 0 


1 Ti 0.8 ,O 3 


225 


3.5 


840 


124 


cms. 


Ba<Sm o.i v o 


l Xi 0.8 )O 3 


280 


7.5 


1130 


130 


tions 


fia(Cd 0.1 V 0 


1 Ti 0.8 )O 3 


350 


8.2 


1290 


135 




Ba(D *0.1 V 0 


1 Ti 0.8>°3 


480 


8.2 


1600 


135 


the 


Ba( *0.1 V 0.1 


Ti 0.8 )O 3 


S30 


12.2 


2200 


125 



FEB 17 2335 14:28 
0VA0"d 



NNOiaaOA 01 9Afr T662C0i 



301 555 9279 PAGE . 07 

yiaaNuxa-ft^-wai ad ss:t>i 2002 li ead 



Table 4 




*0.5 V D.5'°3 
fla<X 0..sVs>°3 



7.B 


260 


154 


10.7 


500 


168 


11.3 


850 


175 


12. 5 


1020 


200 


17.9 


1250 


220 



rate cattll £ «* »« «> menu. » ith 



Table 5 


composition 


T f 


AH 

teal m«i e ~1^ 


8a(La O.1 T *0.1« O .8'° 3 
B * a *0.7 V 0. 1 T io.8 ,O 3 


80 
90 
95 


25 
45 
65 



A glance at the a H values reveal dilution of th* , 

tZl ' SUbSt " Ual 4 "«- Portion of v»* 

Mother significant result of the present study is the obser- 
vation of inching t<j (Tf , „ alttes ^ ^ ^ 
keeping the u, 3 * ion fix4d , Sn ^ ^S-^s!^^' 
Considering the e„er 9y level diagram of an octahedrally sur- 
rounded ^ ion wi,K confi^tion ,np,«, wc expect 



be more ionic 
this the elec 
will be less 
iusfcifi« d by 
these ions x 
Wrgensen has 
that the elec 
k^-v 5 ' and 
transition me- 
cal bond becca 
Our results *j 



Fifth ionizati 



MJ r. GalasBc 
Report OA* 
12} r. Galassc 

SI (1959) 
12} T. Calasso 

83 (1961) 
(4] F. Oalasso 
[5] f. Gai&sso 
[6] F. Calasso 
[7] F. Galasso 
(8) v.s. chine 



_FR0j1_L_URSHINGTON BIBLIOGRflPMC SUC. PHONE ND. ; 301 595 9279 



...Feb. 17 2005 05:04Ptt P9 



be more ionically bonded than Nb and V . As a result of 
this the electron density in the t 2g -orbital of the Ta 5 * ion 
will be less than that in the case of Mb 5 *. V S *. This is also 
justified by considering the fifth ionization potential of 
these ions T (Table 6) which also increases in this sequence. 
Jtfrgensen has concluded from the electron transfer spectra 
that the electron affinity increases in the sequence Ta 5 *- 
Nb S *-v 5 * and from the reduced Racah parameters of several 
transition metal ions (nephelauxetic effect) that the chemi- 
cal bond becomes more oovalent in the sequence 5d-4d-3d group. 
Our results are consistent with the observations of Jtfrgensen. 



Table 6 

fifth loniration potential and electron configuration of B 
metal ions 





Ion 


Electron configuration 


I s (eV) 




V S + 


j.V 


65 




Nb S * 


4» V 


52 




Ta 5 * 


5 S 2 S P « 


4S 



REFERENCES 

[1] F. Galasso, united Aircraft corporation Laboratory, 

Report UAR-810, Jan 1963 
[2] F. Galasso, L. Katz, and P. W*rd, J. Amer.Chem.Soe. 

81 (19S9) 820 

13] F. Galasso, J.R. Barrante, and 1. XaM, J.A»er.Chea.5oe. 
83 (1961) 2830 

[4] F. Galasso, and W.J. Darby, J.Phys.Chem. 66 (1962) 131 
[5] F. Galasso, and J. Pyle, J.Fhys.Chem. 67 (1963) 533 
16] F- Galasso, and J. Pyle, J.Phys.Chem. 67 (1963) 1561 
[7] F. Galasso, and J. Pyle, lnorg.Chea. 2 (1963) 482 
[8] V.S. Chincholkar, J.inorg.Kucl-Chem. 34 (1972) 2973 



FEB 17 2005 14:29 
0T/60"d 



NHOlMyOA 01 9ZfrI662£0«L 



301 595 9279 PAGE. 09 

uiaaNtfrGiy-wai ad ss:fi 2002 l\ H3d 



Feb. 17 2BB5 B5;04Pn P10 




( 9] K. Cade, and V.S. Chincholkar, J . Ch«m . Soc . (Dalton) 

U (1979) 1959 
110] V.S. Chinchollear, Z.Angew.Chem. 26 (1970) 288 
111) V.S. Chinchollear, Ph . D . Thesis . Punc University, 1967 
[12) R.S.Roth, J. Research N»S 56 (19S7) 75 
(13] J. volger. Philips Res. Rep. 7 (1952) 21 
(14) C.K.J^rgensen, "Absorption spectra and chemical bonding 



in complexes" Pergamon Press, 
310-12 



1962, pp. 147, 306 and 



' Present address: Forensic Science Laboratory, Bcmbay~8 



The formation of 
by Solid State re 

*»2 (C 2 0 4 ) 3 , la ( 
Tie reaction ooca 
depending upon tb 
kinetics of foraa 
and MoOj la evala 
controlled nectar 
activation energy 
aole" 1 . 

A reversible phae 
observed at 627 2 
x-ray diff ractioi 



She solid etate i 
la2(C 2 0 4 ) 5 , £a (! 
to gain better qi 
general and the j 
formation of trii 
particular. 
Several (HoO, 
been extensively 
eleotrical, maga 
kinetics and Bee] 
reported u oantil; 
reactivity of ta 
re-exaaine this 
detail. 



FEB 17 2005 14:29 
01/01'd 



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301 595 9279 PPGE.l 

biaaNbx3-ib-wai ad 9S:n 5002 l\ esd 



BRIEF ATTACHMENT J 




IN THE UNITED STATES PATENT AND TRADEMARK OFFICE 



In re Patent Application of 
Applicants: Bednorzetal. 
Serial No.: 08/479,810 
Filed: June 7, 1995 



Date: March 1, 2005 
Docket: YO987-074BZ 
Group Art Unit: 1751 
Examiner: M. Kopec 



For: NEW SUPERCONDUCTIVE COMPOUNDS HAVING HIGH TRANSITION 
TEMPERATURE, METHODS FOR THEIR USE AND PREPARATION 



Commissioner for Patents 
P.O. Box 1450 
Alexandria, VA 22313-1450 



In response to the Office Action dated July 28, 2004, please consider the 
following: 



FIRST SUPPLEMENTAL AMENDMENT 



Sir: 



ATTACHMENT J 



Serial No.: 08/479,810 



Page 1 of 5 



Docket: YO987-074BZ 



PHYSICAL REVIEW B VOLUME 38, NUMBER 10 1 OCTOBER 1988 

Model family of high-temperature superconductors: TU Ca, - iBa 2 Gi« 0 2 (» + 1 ) + m 
(m-l,2;n-l,2,3) 

S. S. P. Parkin, V. Y. Lee. A. I. Nazzal, R. Savoy, T. C. Huang, G. Gorman, and R. Beyers 
IBM Research Division, Almaden Research Center, 650 Harry Road. 
San Jose, California 95120-6099 
(Received 31 May 1988) 
We describe the structures and superconducting properties of six compounds in the Tl-Ca-Ba- 
Cu-O system of the general form, n m Ca.-,Ba2Cu.0 2 fa + i)+-. where m-l or 2 and n-1, 2, or 
3 One of the compounds displays the highest known superconducting transition temperature, 
7V=125 K. The structures of these compounds consist of copper perovskitelikc blocks containing 
1, 2, or 3 CuOj planes separated by one or two Tl-O layers and thus form a model family of 
structures in which both the size and separation of the copper oxide blocks can be independently 
varied The superconducting transition temperature increases with the number of Cu02 planes in 
the perovskitelike block for both the Tl-O monolayer and bilayer compounds. For each pair of 
compounds (m-1.2) with the same number of CuOi planes (same n), the transition tempera- 
tures are similar but are consistently 15-20 K. lower in the materials with single Tl-O layers. 
Variations in the transition temperatures in the double and triple CttOHayer compounds are ob- 
served to correlate with increased densities of intergrowths of related structures. 



Recently 1 " 7 several new high-temperature supercon- 
ductors have been synthesized in the Tl-Ca-Ba-Cu-O sys- 
tem, including Tl2Ca2Ba2Cu30io±x. which displays the 
highest superconducting transition temperature yet found, 
7* e — 125 K. 3 In this article we present data on the struc- 
tures and superconducting properties of six compounds of 
the form n m Ca B -iBa 2 Cu (1 02(„+i)+m, where m-l or 2 
and n-1, 2, or 3. The structures consist of copper 
perovskitelike blocks containing 1, 2, or 3 CuO? planes 
separated by one or two Tl-O layers. These compounds 
thus form a model family of structures in which both the 
size and separation of the copper blocks can be indepen- 
dently varied. We present data that establish that the su- 
perconducting transition temperature increases with the 
number of Cu0 2 planes in the perovskitelike block for 
both the Tl-O monolayer and bilayer compounds. For 
each pair of compounds (m "1, 2) with the same number 
of Cu0 2 planes (same n), the transition temperature is 
15-20 K lower in the material with single Tl-O layers. 
Variations in the transition temperatures in the double 
and triple Cu0 2 layer compounds are observed to corre- 
late with increased densities of intergrowths of related 
structures. 

The samples were prepared by thoroughly mixing suit- 
able amounts of TI2O3, CaO, Ba0 2 , and CuO, and form- 
ing a pellet of this mixture under pressure. The pellet was 
then wrapped in gold foil, sealed in a quartz tube contain- 
ing slightly less than 1 atm of oxygen, and baked for ap- 
proximately 3 h at =880°C. A wide range of starting 
compositions was studied. In most cases the resulting pel- 
let was comprised of several phases. However, for certain 
ranges of starting compositions, the pellets contained only 
one superconducting phase of the form Tl m Ca < i-iBa2- 
Cu„02( II+ i) +in together with minor amounts (< =20%) 
of insulating oxides such as those of Cu, Ca-Cu, Ba-Cu, 
and Tl-Ba. The relative amounts of each phase depended 
on the annealing time and temperature and the rate of 



cooling from this temperature. In particular, for slow 
cooling rates (=100°C/h) the composition of the major 
n m Ca ( ,-iBa2Cu„02G.+i)+m phase more closely matched 
that of the starting composition. The composition and mi- 
crostructure of the pellets were determined from comple- 
mentary powder x-ray diffraction, electron microprobe, 
electron diffraction, and high-resolution transmission elec- 
tron microscopy (TEM) studies. The superconducting 
properties of each pellet were examined by resistivity and 
dc Meissner susceptibility studies. The latter was mea- 
sured with a SHE SQUID magnetometer. Cooling in a 
field of 100 Oe, the magnitude of the Meissner susceptibil- 
ity at 5.5 K ranged from 10% to 35% of the susceptibility 
of a perfect diamagnet of the same volume, neglecting 
small demagnetizing corrections. The magnitude of the 
diamagnetic shielding signal is very dependent on the dis- 
tribution of the normal and superconducting phases within 
the multiphase pellets and in most cases did not give use- 
ful information. The susceptibility data revealed that for 
some pellets the presence of a minority superconducting 
phase resulted in the resistance of the pellet dropping to 
zero at substantially higher temperatures than the T c of 
the majority superconducting phase. This type of behav- 
ior emphasizes the importance of determining the transi- 
tion temperature from a flux exclusion measurement in 
this complex quinary system. These results are summa- 
rized in Table I. 

We have previously described the preparation and prop- 
erties of the three members of the Tl m Ca„-iBa 2 Cu n - 
0 2 (»+D+m family, namely ThCa2Ba 2 Cu 3 Oio (2:2:2:3), 
Tl 2 Ca,Ba 2 Cu20g (2:1:2:2), 3 and niCa2Ba2Cu309 
(1-2-2-3), 4 which display superconducting transition tem- 
peratures of 125, 108, and 110 K, respectively. By sys- 
tematically varying the starting composition of the pellets, 
the related compounds, ThCac^CuiO* (2:0:2:1), 
ThCik^CiuO, (1:0:2:1), and Tl,CaiBa2CU20, 
(1:1:2:2) were synthesized. The unit cells for each phase 

6531 © 1988 The American Physical Society 



PHYSICAL REVIEW B VOLUME 38, NUMBER 10 1 OCTX 

Model family of high-temperature superconductors: Tl m Ca n - iBa 2 Cu fl 02{ fl + i)+m 
(in- 1,2; »- 1,2,3) 

S. S. P. Parkin, V. Y. Lee, A. I. Nazzal, R. Savoy, T. C. Huang, G. Gorman, and R. Beyers 
IBM Research Division, Almaden Research Center. 650 Harry Road, 
San Jose. California 95120-6099 
(Received 31 May 1988) 

We describe the structures and superconducting properties of six compounds in the Tl-Ca-Ba- 
Cu-O system of the general form, Tl m Ca,-iBa2Cu,Oiu+i)+ BI , where m-l or 2 and n-1, 2, or 
3. One of the compounds displays the highest known superconducting transition temperature, 
T e — 125 K. The structures of these compounds consist of copper perovskitelike blocks containing 
1, 2, or 3 CuOj planes separated by one or two Tl-O layers and thus form a model family of 
structures in which both the size and separation of the copper oxide blocks can be independently 
varied. The superconducting transition temperature increases with the number of CuOt planes in 
the perovskitelike block for both the Tl-O monolayer and bilayer compounds. For each pair of 
compounds (m-1,2) with the same number of Cu0 2 planes (same n), the transition tempera- 
tures are similar but are consistently 15-20 K lower in the materials with single Tl-O layers. 
Variations in the transition temperatures in the double and triple Cu02-layer compounds are ob- 
served to correlate with increased densities of intergrowths of related structures. 



Recently'" 7 several new high-temperature supercon- 
ductors have been synthesized in the Tl-Ca-Ba-Cu-O sys- 
tem, including n 2 Ca 2 Ba 2 Cu 3 Oio±;t, which displays the 
highest superconducting transition temperature yet found, 
T e ~ 125 K. 3 In this article we present data on the struc- 
tures and superconducting properties of six compounds of 
the form Tl m Ca n - ! Ba 2 Cu M 0 2 o, + 1 ) +m , where m-l or 2 
and /i~l, 2, or 3. The structures consist of copper 
perovskitelike blocks containing 1, 2, or 3 CuCh planes 
separated by one or two Tl-O layers. These compounds 
thus form a model family of structures in which both the 
size and separation of the copper blocks can be indepen- 
dently varied. We present data that establish that the su- 
perconducting transition temperature increases with the 
number of Cu0 2 planes in the perovskitelike block for 
both the Tl-O monolayer and bilayer compounds. For 
each pair of compounds (m — 1, 2) with the same number 
of Cu0 2 planes (same n), the transition temperature is 
15-20 K lower in the material with single Tl-O layers. 
Variations in the transition temperatures in the double 
and triple Cu0 2 layer compounds are observed to corre- 
late with increased densities of intergrowths of related 
structures. 

The samples were prepared by thoroughly mixing suit- 
able amounts of Tl 2 Oj, CaO, Ba0 2 , and CuO, and form- 
ing a pellet of this mixture under pressure. The pellet was 
then wrapped in gold foil, sealed in a quartz tube contain- 
ing slightly less than 1 atm of oxygen, and baked for ap- 
proximately 3 h at =»880 o C. A wide range of starting 
compositions was studied. In most cases the resulting pel- 
let was comprised of several phases. However, for certain 
ranges of starting compositions, the pellets contained only 
one superconducting phase of the form Tl m Ca <l -|Ba 2 - 
Cu a 0 2 ( a+ i) +m together with minor amounts ( < =20%) 
of insulating oxides such as those of Cu, Ca-Cu, Ba-Cu, 
and Tl-Ba. The relative amounts of each phase depended 
on the annealing time and temperature and the rate of 

38 



cooling from this temperature. In particular, for slow 
cooling rates (=100°C/h) the composition of the major 
Tl ffl Ca n -iBa 2 Cu n 0 2 ( ll +i)+ m phase more closely matched 
that of the starting composition. The composition and mi- 
crostructure of the pellets were determined from comple- 
mentary powder x-ray diffraction, electron microprobe, 
electron diffraction, and high-resolution transmission elec- 
tron microscopy (TEM) studies. The superconducting 
properties of each pellet were examined by resistivity and 
dc Meissner susceptibility studies. The latter was mea- 
sured with a SHE SQUID magnetometer. Cooling in a 
field of 100 Oe, the magnitude of the Meissner susceptibil- 
ity at 5.5 K ranged from 10% to 35% of the susceptibility 
of a perfect diamagnet of the same volume, neglecting 
small demagnetizing corrections. The magnitude of the 
diamagnetic shielding signal is very dependent on the dis- 
tribution of the normal and superconducting phases within 
the multiphase pellets and in most cases did not give use- 
ful information. The susceptibility data revealed that for 
some pellets the presence of a minority superconducting 
phase resulted in the resistance of the pellet dropping to 
zero at substantially higher temperatures than the T c of 
the majority superconducting phase. This type of behav- 
ior emphasizes the importance of determining the transi- 
tion temperature from a flux exclusion measurement in 
this complex quinary system. These results are summa- 
rized in Table I. 

We have previously described the preparation and prop- 
erties of the three members of the TlmCa,,- iBa 2 Cu n - 
O 2 o.+i)+ m family, namely n 2 Ca 2 Ba 2 Cu 3 Oio (2:2:2:3), 3 
n 2 CaiBa 2 Cu 2 0 8 (2:1:2:2), 3 and niCa 2 Ba 2 Cu 3 0 9 
(1:2:2:3), 4 which display superconducting transition tem- 
peratures of 125, 108, and 110 K, respectively. By sys- 
tematically varying the starting composition of the pellets, 
the related compounds, Tl 2 CaoBa 2 CuiO x (2:0:2:1), 
Tl,CaoBa 2 Cu,0, (1:0:2:1), and n,Ca,Ba 2 Cu 2 O x 
(1:1:2:2) were synthesized. The unit cells for each phase 

6531 ©1988 The American Physical Society 



6532 S. S. P. PARKIN et al. 38 

TABLE I. Summary of properties of TUCa.-1Ba2Cu.Ox 
Cone. Relative composition Lattice parameters Superlattice 



ratio 


Tl 


Ca 


Ba 


Cu 


O 


Symmetry 


a (A) 


c (A) 


wave vector (k) 


T c (K) 














Tl Ca 


9a2Cu.Ox 








1:0:2:1 


1.2 


0.0 


2 


0.7 


4.8 


PA/mmm 


3.869(2) 


9.694(9) 


a 


b 


1:1:2:2 


1.1 


0.9 


2 


2.1 


7.1 


P4/mmm 


3.8505(7) 


12.728(2) 


(0.29,0,0.5) 


65-85 


1:2:2:3 


1.1 


0.8 


2 


3.0 


9.7 


PA/mmm 


3.8429(6) 


15.871(3) 


(0.29,0,0.5) 


100-110 














ThCa.-, 


BajGuO* 








2:0:2:1 


1.9 


0.0 


2 


1.1 


6.4 


F/mmm' 


a -5.445(2) 


23.172(6) 


(008,0.24, 1> C 


b 
















6-5.492(1) 








2*2.1" 


1.8 


0 


2 


1.1 


6.4 


F/mmm' 


a -5.4634(3) 
b~a 


23.161(1) 


(008,0.24, 1> C 


20 


2.0:2:1 


1.8 


0.02 


2 


1.1 


6.3 


14/mmm 


3.8587(4) 


23.152(2) 


(016,0.08, l> e 


15-20 


11:2:2 


1.7 


0.9 


2 


2.3 


8.1 


14/mmm 


3.857(1) 


29.39(1) 


(0.17,0,1) 


95-108 


2:2:2:3 


1.6 


1.8 


2 


3.1 


10.1 


14/mmm 


3.822(4) 


36.26(3) 


(0.17,0,1) 


118-125 



'No superlattice spots observed. 

b Nonmetallic or weakly metallic samples with no superconducting transition observed in resistivity and magnetic susceptibility studies 
for temperatures down to 4.2 K. 

The symmetry of the structure is onhorhombic if the observed superlattice is ignored. Taking the superlattice into account lowers 
the symmetry to monoclinic. 

'Sample prepared from a Cu-rich starting composition, ThBajCui. 

The superstructure is identical to that for the orthorhombic 2:0:2:1 polymorph. 



n m Ca n -iBa2Cu n 02(,,+i)+ m family can be uniquely 
identified. The peak systematically shifts to lower angles 
as n increases within both the TliCa,,-|Ba2Cu,02«+3 and 
n 2 Ca n - 1 Ba 2 Cu.Oz, +4 families, consistent with an ex- 
pansion of the unit cell along the c axis by the addition of 
extra O1O2 and Ca planes. The peaks are in all cases at 
lower angles in the n2Ca B -|Ba 2 Cu B 02.+4 compounds 
compared to the corresponding n]Ca„-iBa 2 Cu rl 02 JI +3 
compound, consistent with the increased number of Tl-O 
layers in the Ti2Ca,,-iBa2Cu,,02«+4 compounds. The 
peaks are asymmetrically broadened to low angles be- 
cause of geometrical aberrations in the focusing condition 
resulting from the flat specimens used. 8 The arrangement 
of the cations in the various compounds is shown in Fig. 2. 
The positions of the oxygen atoms are inferred by compar- 
ison wjth related structures in the La 2 -xSr x Cu0 4 , 
YBazCuaO,, and Bi2Sr 2 CaiCu 2 0, families. 9 "" The six 
structures are comprised of Cu perovskitelike blocks con- 
taining one, two, or three Cu0 2 planes sandwiched be- 
tween Tl-O monolayers (1:0:2:1, 1:1:2:2, and 1:2:2:3 com- 
pounds) or bilayers (2:0:2:1, 2:1:2:2, 2:2:2:3 compounds). 
The Ba cations are located in planes adjacent to the Tl-O 
unit and the Ca cations form planes within the interior of 
the Cu perovskitelike unit 

Since the preparation, structure, and properties of the 
double and triple Cu0 2 layer oxides appear to be much 
less complex than those of the single Cu0 2 layer oxides 
for both the monolayer and bilayer Tl-O compounds, we 
will discuss these groups of compounds separately. As de- 
scribed earlier, for each of the n —2 and n — 3 compounds 
a single tetragonal structure was found. An important 
structural feature of these compounds observed by TEM, 
scanning electron microscopy (SEM), and electron mi- 
croprobe studies are intergrowths of structures related to 
the primary phase by the addition or removal of G1O2 or 
Tl-O layers. For some samples SEM images showed con- 
trast striations — 5-10 /im in width within individual 



were determined from powder x-ray diffraction patterns 
extending from 20-3° to 70° and verified by electron 
diffraction studies. These studies showed that all of the 
Tl m Ca fl -iBa 2 Cu B O20i+i)+ m compounds have tetragonal 
cells at room temperature. The TiiCa ( ,-iBa2Cu )I 02»+3 
compounds contain Tl-O monolayers, resulting in primi- 
tive tetragonal cells, whereas the Tl2Ca ( ,-iBa2Cu II 02«+4 
compounds contain Tl-O bilayers, resulting in body- 
centered tetragonal cells. The lattice parameters and 
symmetries of the various structures are included in Table 
I. As discussed later, the 2:0:2:1 compound also has an 
orthorhombic polymorph. As shown in Fig. 1, each oxide 
has a single peak in the low-angle portion 
(3° < 20 < 10°) of its x-ray diffraction pattern which re- 
sults from the large c/a ratio in each structure. These 
peaks, (001) for m-1 and (002) for m-2, serve as 
fingerprints with which each of the compounds within the 



TI,Ca n . 1 Ba 2 Cu n O x TI 2 Ca„., Ba 2 Cu n O x 




26 (deg) 



20(deg) 

FIG. 1. Low-angle section of the powder x-ra; 
patterns for the six phases TL,Ca.- 1 Ba2Cu«0 2 o.+ 
2;n -1,2, 3). 



38 



MODEL FAMILY OF HIGH-TEMPERATURE . 



6533 




TfeCa,,-! Ba 2 Cu n 0 2n +4 



n=1 n=2 n=3 

FIG. 2. Nominal structures of the six TU,Ca«-iBa2Cu„- 
Om,+i)+i» phases for /i — 1, 2andm — 1,2,3. 



grains which result from intergrowths of regions with 
different proportions of heavy atoms. TEM studies re- 
vealed the existence of intergrowths on much finer length 
scales, as demonstrated in Fig. 3 for a sample prepared 
from a starting composition of Tlo.gsCaiBa2Cu 2 . Figure 
3(a) shows a selected area diffraction pattern along b* 
which indicates that this grain contains both 1:1:2:2 and 
1:2:2:3 phases. Indeed Meissner data on this sample (in- 
cluded in Fig 4(d)] indicate two superconducting transi- 
tions with 7V— 65 and —105 K, consistent with the pres- 
ence of extended regions of two distinct phases. Co in- 
tently, tne c i attice parameters of the 1 : 1 :2:2 and 1 :2:2:3 
phases are almost exactly in the ration of 4/5 so that every 
fifth 1:2:2:3 hOl spot coincides with every fourth 1:1:2:2 
AO/ spot in Figure 3(a). High-resolution TEM micro- 
graphs in Figs. 3(b) and 3(c) show intergrowths of the 




FIG. 3. (a) [010] selected area diffraction (SAD) pattern 
and (b) corresponding image of crystallites containing regions of 
1:2:2:3 and 1:1:2:2. The arrows in (b) denote unit-cell thick in- 
tergrowths of 1:1:2:2 in 1:2:2:3. (c) High-resolution transmis- 
sion electron micrograph of one unit-cell thick 1:1:2:2 inter- 
growth in 1:2:2:3. 



S. S. P. PARKIN eta/. 



6534 




80 100 120 140 40 80 120 



Temperature (K) 

FIG. 4. Meissner susceptibility vs temperature for an applied 
field of 100 Oe for materials with starting cation composition, 
(a) TliBa2Cuj (•), TIjCaaosBajCui.os (0,+), and TljCaau- 
BajCuns (▼); (b) TliCajBajCuj (•), TfeCaiBajCuj (o), and 
TlusCaiBajCu: (■); (c) Tl,Ca 2 Ba2Cu3 (■), TltCa2jBa,Cuj (o), 
and Tl,Ca 3 Ba,Cu3 (•); (d) TlojsCaiBaiOfc (O), n l CaiBa 2 Cu 2 
(•,+), and T1o.i]Ca2Ba2Cu3 (t). The phases present in the pel- 
let giving rise to the diamagnetic susceptibility are (a) 2:0:2:1 
and 2:1:2:2, (b) 2:1:2:2, (c) 2:2:2:3, and (d) 1:1:2:2 and 1:2:2:3. 



1:1:2:2 and 1:2:2:3 phases on length scales extending from 
— l/<m down to one unit celL The intergrowths are ran- 
domly distributed along the stacking axis. Isolated inter- 
growths comprising four C11O2 planes were found in some 
samples (see Fig. 5) but no evidence was found for ex- 
tended intergrowths comprising greater than three C11O2 
layers in these or other samples especially prepared from 
Cu- and Ca-rich starting compositions. A second type of 
intergrowth was observed in samples of the 1:2:2:3 phase 
in which an extra Tl-O plane was occasionally inserted be- 
tween the Cu perovskitelike units, creating local regions of 
the 2:2:2:3 phase. Microprobe data show that the Tl con- 
tent is systematically high in the compounds containing 
single Tl-O layers and systematically low in those com- 




FIG. 5. High-resolution TEM image of an isolated four- 
C11O2- layer intergrowth. The markers denote the positions of 
the Cu columns. 



pounds with Tl-O bilayers (see Table I) thus suggesting 
that intergrowths of Tl-O monolayers in the Tl-O bilayers 
materials and Tl-O bilayers in the Tl-O monolayer com- 
pounds are a general feature of these materials. 

Meissner data (see Fig. 4) established that T e can take 
a range of values for all of the double and triple Cu0 2 lay- 
er compounds— T c - 95- 108 K for 2:1:2:2, 7^ = 118-125 
K for 2:2:2:3, T e =65-85 K for 1:1:2:2, and T^lOO 
-110 K for 1:2:2:3. For a given compound, x-ray 
diffraction and microprobe studies did not detect any ob- 
vious difference between the samples with different transi- 
tion temperatures. TEM studies, however, showed a clear 
correlation between the density of intergrowths and T e . 
For the 2:1:2:2, 2:2:2:3, and 1:2:2:3 phases the material 
with no intergrowths displayed the highest transition tem- 
perature, whereas for the 1:1:2:2 compound the sample 
with the lowest density of intergrowths had the lowest T c . 
As the density of intergrowths increased we observed that 
T e systematically decreases or increases, respectively. It 
is possible that the structural or electronic modifications 
caused by the intergrowths are directly responsible for the 
decreased transition temperatures. Alternatively the pres- 
ence of the intergrowths may simply reflect a means 
whereby the system accommodates, to some extent, off- 
stoichiometry in the cation sites which in turn may 
influence T t . It is difficult to determine whether it is the 
local change in structure or composition which is responsi- 
ble for the decrease in T c since these are concurrent 
changes. 

A second important structural feature found in all of 
the double and triple C11O2 layer compounds is the pres- 
ence of weak superlattice reflections in the selected area, 
electron diffraction patterns. These reflections are consid- 
erably weaker than those previously found in the 
BijS^CaiCuaO* compound 12-16 and indicate different 
structural modulations than those in the Bi2Sr 2 CaiCu 2 O x 
compound. The patterns can be described by a set of 
symmetry-related wave vectors, k. Each wave vector de- 
scribes a pair of reflections symmetrically disposed a re- 
ciprocal distance | k | along k on either side of each Bragg 
peak, which would be consistent with a sinusoidal modula- 
tion of the charge density along this direction. 17 The pos- 
sibility that each k corresponds to a different crystal vari- 
ant with lowered symmetry is unresolved. The Tl-O 
monolayer and bilayer families each display a distinctive 
pattern of superlattice reflections, shown schematically in 
Figs. 6(a) and 6(b). One example of electron diffraction 
patterns showing the superlattice reflections is given in 
Fig. 7 for the 1 : 1 :2:2 phase. 

The structure and properties of the single Cu0 2 layer 
compounds are more sensitive to the preparation condi- 
tions than those of the double and triple Cu0 2 layer com- 
pounds. When prepared from a Tl 2 Ba 2 Cui starting com- 
position, the 2:0:2: L compound has a face-centered ortho- 
rhombic cell and is not superconducting. The material is 
heavily twinned with twin planes of {l 10} type in the or- 
thorhombic cell. This cell is related to the tetragonal cell 
by a rotation of =45° about the c axis with a and b in- 
creased in size by a factor of —yfl. However when the 
2:0:2:1 compound is prepared from a Cu-rich starting 
composition, Tl 2 Ba 2 Cu 2 , the compound is superconduct- 



MODEL FAMILY OF HIGH-TEMPERATURE . 







FIG. 6. Schematic diagram of the arrangement of superlat- 
tice reflections about the fundamental reflections for (a) the 
1:1:2:2 and 1:2:2:3 phases, (b) the 2:1:2:2 and 2:2:2:3 phases, (c) 
the 2:0:2:1 phase. The fundamental reflections are shown as 
solid circles, and those which are systematically absent are 
shown as dashed circles. The superstructure is shown by open 
circles and the corresponding wave vectors by bold arrows. 



ing at =20 K. While x-ray data indicate the structure is 
pseudotetragonal, transmission electron micrographs re- 
veal a tweed pattern which is consistent with local ortho- 
rhombic distortion. A tetragonal polymorph with no evi- 
dence from TEM studies of either an average or local or- 
thorhombic distortion can be formed by preparing the 
compound from a pellet containing a small amount of Ca 
(Tl:Ca:Ba:Cu-2:y:2:l+.y, with y =0.05-0. 15). This po- 
lymorph is also superconducting with a T e which is in- 
dependent of the amount of Ca in the starting composition 
but weakly dependent on the annealing time— T e —15 
and 20 K for anneal times at 880 °C of 3 and 9 h, respec- 
tively. As suggested by the Meissner data in Fig. 4(a) 
these pellets contain, in addition to the tetragonal 2:0:2:1 
phase, a substantial amount of the 2:1:2:2 phase which in- 
creases as the proportion of Ca in the starting composition 
is increased. There is a sufficient amount of this phase 
that the resistance of these pellets actually drops to zero at 



FIG. 7. (a) 1100] and (b) [001] selected area diffraction pat- 
terns from crystallites of 1:1:2:2 showing superlattice reflections. 



T c — 100 K. The Meissner data in Fig. 4(a) show that for 
j>=0.05 the ratio of 2:1:2:2 to 2:0:2:1 is about 8% and for 
.y =0.1 5 the ratio is increased to =30%. Electron mi- 
croprobe analysis shows that only a small amount of Ca 
(=0.2 at.%) is incorporated into the 2:0:2:1 grains and 
consequently the role of the Ca doping in changing the 
structure and properties of the 2:0:2:1 material is unclear. 
Moreover there are reports that the 2:0:2:1 phase can be 
prepared without Ca with a transition temperature as high 
as =85 K. 5 Both polymorphs of the 2:0:2:1 structures 
display a similar superlattice with an approximate wave 
vector, k- [0.08,0.24,1] in the orthorhombic setting. 
Taking the superlattice into account lowers the symmetry 
of both the orthorhombic and tetragonal structures to 
monoclinic with the c axis being unique. As shown in Fig. 
8 this superstructure is different from those found in the 
double and triple Cu0 2 layer compounds. 

The other member of the Tl m Ca )1 -|Ba2Cu n O20,+i)+m 
family which contains single Cu0 2 layers, the 1:0:2:1 
phase, has a primitive tetragonal cell and is not supercon- 
ducting for the wide range of preparative conditions con- 
sidered in this study, including growth from Cu-rich or 
Ca -doped starting compositions. No superstructures have 
been observed in these crystals so far. 



S. S. P. PARKIN et at. 





* • « • 




Number of Cu-0 2 Layers 

FIG. 9. Dependence of T, on the number of C11O2 planes 
within the Cu perovskitelike unit for the TliCa,,-iBa2Cu„02*+3 
(■) and Tl2Ca„- 1 Ba2Cu,Oi, +< (•, this work; O, Ref. S) series of 
compounds. The dashed vertical lines correspond to the varia- 
tions in T, found for each phase. □ corresponds to data for (Tl, 
Bi),(Ca,Sr)2Cu,O x (Ref. 21). 



FIG. 8. (a) (100], (b) II 10], and (c) [001] selected area 
diffraction patterns from a crystallite of 2:0:2:1. 



As shown in Table I there is no obvious correlation of 
superlattice structure with the superconducting properties 
of the Tl„Ca 1 ,-,Ba2Cu B O20, + ,)+ ) « compounds. Note 
that in the closely related compound, Bi 2 SriCa2Cu 2 0 Jt) it 
has recently been proposed that the observed incommens- 
urate superlattice corresponds to a distortion of both the 
Bi-O and Cu0 2 planes resulting from ordered vacancies 



on the Sr sites. 16 The vacancies are postulated to deter- 
mine the carrier density on the O1O2 planes and so 
influence the T e in a manner similar to that first noted by 
Schafer, Penney, and Olsen for the La 2 -xSr x Cu04- y 
compounds. 18 The number of different superlattice struc- 
tures found in the Tl-Ca-Ba-Cu-O system provides a more 
extensive basis with which to test such hypotheses. Indeed 
it may be significant that, as shown in Table I, there are 
important variations in stoichiometry away from the ideal 
stoichiometrics expected for the various Tl„,Ca„_iBa2- 
Cu„C>2G.+i)+m phases. In particular, the [Tl]/[Ba] ratio 
is higher for the n — 1 compounds compared to those for 
n —2 and n—3. Band-structure calculations of both the 
Tl m Ca n -iBa2Cu n O20,+D+m compounds and Bi2SriCa 2 - 
Cu 2 O x indicate that the stoichiometry of the Tl-O and 
Bi-O layers would have a profound impact on the carrier 
density in these materials. 19,20 The extent of off- 
stoichiometry on the cation or the oxygen sites in the Tl- 
Ca-Ba-Cu-O phases requires further study. Note also 
that one group has recently prepared a complex material 
of the form (T13i)i(Ca,Sr) 2 CuiO, with the 1:0:2:1 struc- 
ture which appears to superconduct at temperatures of up 
to 50 K (Ref. 21). The variation of properties of the sin- 
gle CUO2 layers compounds provides a fertile area for fur- 
ther study and highlights the difficulties in preparing these 
multicomponent oxides in a controlled manner. 

In conclusion, these studies have shown that the super- 
conducting transition temperature increases with the 
number of Cu0 2 planes in the perovskitelike unit for both 
the T^CaB-^CuaOto+a and Tl 2 Ca II -iBa 2 Cu ( ,0 2 »+4 
structures (Fig. 9). A similar dependency is found in both 
series of compounds with an increased spread of T e as the 
number of Cu0 2 planes is reduced. The range of T e in the 
double and triple Cu0 2 layer compounds correlates with 
the density of intergrowth defects. No such defects have 
ben observed so far in the single O1O2 layer compounds, 



MODEL FAMILY OF HIGH-TEMPERATURE . . . 



even when doped with Ca. One might speculate that in 
this case the variation in transition temperature may re- 
sult from variations in cation or oxygen site occupancy. 
The increase in T e as n increases may be accounted for by 
various theories, including several based on the BCS 
theory 19 and others invoking more exotic mechanisms 
such as the resonating-valence-bond model. 22 The variety 
of structures and properties in the Tl-Ca-Ba-Cu-O system 
provides a model family of compounds with which various 



theories of high-temperature superconductivity can be 
evaluated. 

We are indebted to S. J. La Placa, F. Herman, and J. B. 
Torrance for many useful discussions. We thank C. C. 
Torardi, R. B. Flippen, and R. M. Hazen for discussions 
regarding the 2:0:2:1 compound. We are grateful to Pro- 
fessor Sinclair at Stanford for the use of his electron mi- 
croscope. 



'Z. Z. Sheng and A. M. Hermann, Nature (London) 332, 138 

(1988); 332, 55 (1988). 
2 R. M. Hazen, L. W. Finger, R. J. Angel, C. T. Prewitt, N. L. 

Ross, C. G. Hadidiacos, P. J. Heaney, D. R. Veblen, Z. Z. 

Sheng, A. El Ali, and A. M. Hermann, Phys. Rev. Lett 60, 

1657 (1988). 

3 S. S. P. Parkin, V. Y. Lee, E. M. Engler, A. I. Nazzal, T. C. 

Huang, G. Gorman, R. Savoy, and R. Beyers, Phys. Rev. Lett. 

60, 2539 (1988). 
4 S. S. P. Parkin, V. Y. Lee, A. I. Nazzal, R. Savoy, R. Beyers, 

and S. J. La Placa, Phys. Rev. Lett 61, 750 (1988). 
5 C. C. Torardi, M. A Subramanian, J. C. Calabrese, J. 

Gopalakrishnan, K. J. Morrissey, T. R. Askew, R. B. Flippen, 

U. Chowdry, and A. W. Sleight, Science 240, 631 (1988). 
6 M. A Subramanian, J. C. Calabrese, C. C. Torardi, J. 

Gopalakrishnan, T. R. Askew, R. B. Flippen, K. J. Morrissey, 

U. Chowdry, and A. W. Sleight, Nature (London) 332, 420 

(1988). 

7 S. Kondoh, Y. Ando, M. Onoda, and M. Sato, Solid State 
Commun. 65, 1329 (1988). 

'W. Parrish, X-ray and Electron Methods of Analysis (Plenum, 
New York, 1968). 

9 J. M. Tarascon, Y. Le Page, P. Barboux, B. G. Bagley, L. H. 
Greene, W. R. McKinnon, G. W. Hull, M. Giroud, and D. M. 
Hwang, Phys. Rev. B 37, 9382 (1988). 

10 S. A Sunshine, T. Siegrist, L. F. Schneemeyer, D. W. Mur- 
phy, R. J. Cava, B. Batlogg, R. B. van Dover, R. M. Fleming, 
S. H. Glarum, S. Nakahara, R. Farrow, J. J. Krajewski, S. M. 
Zahurak, J. V. Waszczak, J. H. Marshall, P. Marsh, L. W. 



Rupp, and W. F. Peck, Phys. Rev. B 38, 893 (1988). 
"J. B. Torrance, Y. Tokura, S. J. LaPlaca, T. C. Huang, R. J. 
Savoy, and A. I. Nazzal, Solid State Commun. 66, 703 
(1988). 

12 T. M. Shaw, S. A. Shivanshankar, S. J. LaPlaca, J. J. Cuomo, 
T. R. McGuire, R. A. Roy, K. H. Kelleher, and D. S. Yee, 
Phys. Rev. B 37, 9856 (1988). 

13 D. R. Veblen, P. J. Heaney, R. J. Angel, L. W. Finger, R. M. 
Hazen, C. T. Prewitt, N. L. Ross, C. W. Chu, P. H. Hor, and 
R. L. Meng, Nature (London) 332, 334 (1988). 

14 E. A. Hewat, M. Dupuy, P. Bordet, J. J. Capponi, C. Chail- 
lout, J. L. Hodeau, and M. Marczio, Nature (London) 333, 
53 (1988). 

,S H. W. Zandbergen, Y. K. Huang, M. J. V. Menken, J. N. Li, 
K. Kadowaki, A. A. Menovsky, G. van Tendeloo, and S. 
Amelinckx, Nature (London) 332, 620 (1988). 

,6 P. L. Gai and P. Day (unpublished). 

l7 P. M. De Wolff, Acta Crystallogr. Sec. A 30, 777 (1974). 

18 M. W. Shafer, T. Penney, and B. L. Olsen, Phys. Rev. B 36, 
4047 (1987). 

"M. S. Hybertson and L. F. Mattheiss. Phys. Rev. Lett. 60, 
1661 (1988). 

M F. Herman, R. V. Kasowski, and W. Y. Hsu, Phys. Rev. B 38, 
204 (1988); F. Herman, R. V. Kasowski, S. J. La Placa, and 
S. S. P. Parkin (unpublished). 

2I P. Haldar, A. Roig-Janicki, S. Sridhar, and B. C. Giessen (un- 
published). 

^J. M. Wheatley, T. C. Hsu, and P. W. Anderson, Nature 
(London) 333, 121 (1988). 



FIG. 3. (a) [010] selected area diffraction (SAD) pattern 
and (b) corresponding image of crystallites containing regions of 
1:2:2:3 and 1:1:2:2. The arrows in (b) denote unit-cell thick in- 
tergrowths of 1:1:2:2 in 1:2:2:3. (c) High-resolution transmis-' 
ston electron micrograph of one unit-cell thick 1:1:2:2 inter- 
growth in 1:2:2:3. 



FIG. 5. High-resolution TEM image of an isolated four- 
CuOrUiyeF intcrgrowth. The markers denote the positions of 
the Go columns. 




FIG. 1. (a) flOOl and (b) [001] selected area diffraction pat- 
terns from crystallites of 1:1:2:2 showing superlattice reflections. 




FIG. 8. (a) UOOl, (b) [110]. and (c) [001] selected area 
diffraction patterns from a crystallite of 2.-0:2:1. 



BRIEF ATTACHMENT K 





IN THE UNITED STATES PATENT AND TRADEMARK OFFICE 



In re Patent Application of 
Applicants: Bednorz et al. 
Serial No.: 08/479,810 
Filed: June 7, 1995 



Date: March 1, 2005 
Docket: YO987-074BZ 
Group Art Unit: 1751 
Examiner: M. Kopec 



For: NEW SUPERCONDUCTIVE COMPOUNDS HAVING HIGH TRANSITION 
TEMPERATURE, METHODS FOR THEIR USE AND PREPARATION 



Commissioner for Patents 
P.O. Box 1450 
Alexandria, VA 22313-1450 



In response to the Office Action dated July 28, 2004, please consider the 
following: 



FIRST SUPPLEMENTAL AMENDMENT 



Sir: 



ATTACHMENT K 



Serial No.: 08/479,810 



Page 1 of 5 



Docket: YO987-074BZ 



Japanese Journal of Applied Physics 

Vol. 27, No. 2, February, 1988, pp. L209-L210 



A New High-Tc Oxide Superconductor without a Rare Earth Element 

Hiroshi Maeda, Yoshiaki Tanaka, Masao Fukutomi and Toshihisa Asano 
National Research Institute for Metals, Tsukuba Laboratories, Ibaraki 305 
(Received January 22, 1988; accepted for publication January 23, 1988) 

We have discovered a new high-7; oxide superconductor of the Bi-Sr-Ca-Cu-O system without any rare earth de- 
ment. The oxide BiSrCaCu,O x has T c of about 105 K, higher than that of YBa 2 Cu 3 0, by more than 10 K. In this oxide, 
the coexistence of Sr and Ca is necessary to obtain high 7"^ 

KEYWORDS: oxide superconductor, Bi-Sr-Ca-Cu-0 system, rare earth, high T v new stable superconductor 



Soon after the discovery of high-7; superconductors of 
the layered perovskites (LaBa^CuCV* and (LaSrfcCufV 
with T c of about 40 K, YBa 2 Cu 3 07 3 > with T e of 94 K was 
synthesized. The discovery of these materials stimulated 
many researchers to investigate new oxide superconduc- 
tors of still higher T c and extensive studies have been car- 
ried out to search for these oxides. Up to now, however, 
no new stable supercondutors with T c higher than that of 
YBa 2 Cu 3 0 7 have been reported. The values of T c have 
not improved by the substitution of other rare earth 
elements for yttrium. 

In order to find high- 7; superconductors, we believe 
that it is important to investigate other classes of oxides 
which do not include rare earth elements. This led us to 
study the superconducting oxide system including the 
Vb-element group such as Bi and Sb of trivalent 
elements, and we discovered a new high-7; superconduct- 
ing material BiSrCaCu 2 C>. This oxide has T c of about 
105 K, being higher than that of YBa 2 Cu 3 0 7 by more 
than 10 K. 

The value of T c in the Bi-Sr-Cu-O oxide system which 
does not include Ca is very low being about 8 K. 4J > In 
order to obtain high T c , the coexistance of Sr and Ca in 
the Bi oxide system is found to be absolutely necessary. 

The Bi-Sr-Ca-Cu-O oxide samples were prepared 
from powder reagents of Bi 2 0 3 , SrCOj, CaCOj and CuO. 
The appropriate amounts of powders were mixed, calcin- 
ed at 800-870°C for 5 h, thoroughly reground and then 
cold-pressed into disk-shape pellets (20 mm in diameter 
and 2 mm in thickness) at a pressure of 2 ton/cm 2 . Most 
of the pellets were sintered at about 870°C in air or in an 
oxygen atmosphere and then furnace-cooled to room tem- 
perature. 

The electrical resistivity was measured by the standard 
four-probe method for a bar-shaped specimen of about 
1x2x20 mm 3 cut out from the pellets. Magnetization 
measurements were carried out with a vibrating sample 
magnetometer. The temperature was measured by 
Au7%Fe-Chromel thermocouples. Figure 1 shows the re- 
sistivity vs temperatue curves of BiSrCaCujQ, oxides 
thus prepared. Specimen (a) was sintered at a relatively 
low temperature of 800°C for 8 h while specimen (b) was 
sintered at a higher temperature of 882°C for 20min 
followed by annealing at 872°C for 9 h. In the case of the 
lower sintering temperatue, the onset temperature (7T ) 
of the superconducting transition is about 83 K and the 
zero resistance state (7^) is reached at 75 K (low-7; 



phase). On the other hand, in the case of a higher sinter- 
ing temperature, a high-7; phase appears, the onset tem- 
perature of which is about 120 K and T c extraporated to 
zero resistance is as high as 105 K. The value of Tf is 
higher than that of YBa 2 Cu 3 0 7 by more than 10 K. Since 
a little amount of the low-7; phase still remained in the 
sample, a complete zero resistance state is achieved at 
75 K which corresponds to that of the low-7; phase. We 
have not succeeded in synthesizing the oxides with a 
single phase of the high-7; material at this moment. 
From our preliminary experiments, we know that sinter- 
ing at high temperatures for a short duration of time is 
effective enough to increase the relative amount of the 
high-7; phase. This may indicate that the high-7; phase is 
stable at elevated temperatures. 

Figure 2 shows the magnetization vs temperature curve 
for the specimen (b) in Fig. 1 which was sintered at the 
higher temperatures. A Meissner effect showing a perfect 
diamagnetic state is observed exactly in the same tempera- 
ture range as in curve (a) shown in Fig. 1. We conclude, 
therefore, that the present high-7; phase is indeed super- 
conducting. 

The high-7; phase appears near the composition ratios 
of Bi:Sr:Ca= 1:1:1. As the composition deviates from 





r 

BhSriCcCUiOx 







0 40 80 120 160 200 240 



Temperature ( K ) 
Fig. 1. Temperature dependence of resistivities in B^Sr.Ca^jO, ox- 
ides (a) sintered in air at S0O°C for 8 h, then cooled in a furnace and 
(b) sintered at 882°C for 20 min followed by annealing at 872°C for 
9h. 



L209 



Japanese Journal of Applied Physics 

Vol. 27, No. 2, February, 1988, pp. L209-L210 



A New High- J c Oxide Superconductor without a Rare Earth Element 

Hiroshi Maeda, Yoshiaki Tanaka, Masao Fukutomi and Toshihisa Asano 
National Research Institute for Metals. Tsukuba Laboratories, Ibaraki 305 
(Received January 22, 1988; accepted for publication January 23, 1988) 

We have discovered a new high-r c oxide superconductor of the Bi-Sr-Ca-Cu-O system without any rare earth ele- 
ment. The oxide BiSrCaCu 2 O x has T c of about 105 K, higher than that of YBa 2 Cu,0, by more than 10 K. In this oxide, 
the coexistence of Sr and Ca is necessary to obtain high T c . 

KEYWORDS: oxide superconductor, Bi-Sr-Ca-Cu-0 system, rare earth, high T„ new stable superconductor 



Soon after the discovery of high-T'c superconductors of 
the layered perovskites (LaBafcCuCV* and (LaSrfcCuOi 2 ' 
with T c of about 40 K, YBa 2 Cu 3 07 3) with 7; of 94 K was 
synthesized. The discovery of these materials stimulated 
many researchers to investigate new oxide superconduc- 
tors of still higher T c and extensive studies have been car- 
ried out to search for these oxides. Up to now, however, 
no new stable supercondutors with 7* c higher than that of 
YBa 2 Cu 3 0 7 have been reported. The values of T c have 
not improved by the substitution of other rare earth 
elements for yttrium. 

In order to find high-T'c superconductors, we believe 
that it is important to investigate other classes of oxides 
which do not include rare earth elements. This led us to 
study the superconducting oxide system including the 
Vb-element group such as Bi and Sb of trivalent 
elements, and we discovered a new high-T'c superconduct- 
ing material BiSrCaCu 2 0,. This oxide has T c of about 
105 K, being higher than that of YBa 2 Cu 3 C>7 by more 
than 10 K. 

The value of T c in the Bi-Sr-Cu-O oxide system which 
does not include Ca is very low being about 8 K. 4,S) In 
order to obtain high T c , the coexistance of Sr and Ca in 
the Bi oxide system is found to be absolutely necessary. 

The Bi-Sr-Ca-Cu-O oxide samples were prepared 
from powder reagents of Bi 2 0 3 , SrC0 3 , CaC0 3 and CuO. 
The appropriate amounts of powders were mixed, calcin- 
ed at 800-870°C for 5 h, thoroughly reground and then 
cold-pressed into disk-shape pellets (20 mm in diameter 
and 2 mm in thickness) at a pressure of 2 ton/cm 2 . Most 
of the pellets were sintered at about 870°C in air or in an 
oxygen atmosphere and then furnace-cooled to room tem- 
perature. 

The electrical resistivity was measured by the standard 
four-probe method for a bar-shaped specimen of about 
1x2x20 mm 5 cut out from the pellets. Magnetization 
measurements were carried out with a vibrating sample 
magnetometer. The temperature was measured by 
Au7%Fe-Chromel thermocouples. Figure 1 shows the re- 
sistivity vs temperatue curves of BiSrCaCu 2 O x oxides 
thus prepared. Specimen (a) was sintered at a relatively 
low temperature of 800°C for 8 h while specimen (b) was 
sintered at a higher temperature of 882°C for 20 min 
followed by annealing at 872 °C for 9 h. In the case of the 
lower sintering temperatue, the onset temperature (7?") 
of the superconducting transition is about 83 K and the 
zero resistance state (Tf) is reached at 75 K (low-7; 



phase). On the other hand, in the case of a higher sinter- 
ing temperature, a high-r c phase appears, the onset tem- 
perature of which is about 120 K and T c extraporated to 
zero resistance is as high as 105 K. The value of Tf is 
higher than that of YBa 2 Cu 3 0 7 by more than 10 K. Since 
a little amount of the low-Tc phase still remained in the 
sample, a complete zero resistance state is achieved at 
75 K which corresponds to that of the low-rc phase. We 
have not succeeded in synthesizing the oxides with a 
single phase of the high-T'c material at this moment. 
From our preliminary experiments, we know that sinter- 
ing at high temperatures for a short duration of time is 
effective enough to increase the relative amount of the 
high-T'c phase. This may indicate that the high-T'c phase is 
stable at elevated temperatures. 

Figure 2 shows the magnetization vs temperature curve 
for the specimen (b) in Fig. 1 which was sintered at the 
higher temperatures. A Meissner effect showing a perfect 
diamagnetic state is observed exactly in the same tempera- 
ture range as in curve (a) shown in Fig. 1. We conclude, 
therefore, that the present high- 7; phase is indeed super- 
conducting. 

The high- 7c phase appears near the composition ratios 
of Bi:Sr:Ca=l:l:l. As the composition deviates from 




0 40 B0 120 160 200 240 



Temperature ( K ) 
Fig. 1. Temperature dependence of resistivities in BiiSr^CujO, ox- 
ides (a) sintered in air at 800°C for 8 h, then cooled in a furnace and 
(b) sintered at 882°C for 20 min followed by annealing at 872°C for 
9h. 



L209 



Hiroshi Maeda, Yoshiaki Tanaka, Masao Fukutomi and Toshihisa Asano 



FIELD (kOe>; 
NO. of POINTS; 
MASS It); 



H= .1 
N= 719 
m= .08106 



Fig. 2. Magnetization of Bi,Sr,CaiCu 2 O x for the sample (b) in Fig. 1 in a field of 100 Oe. 




Fig. 3. X-ray (Cuko) 



2 S (degree ) 

pattern of the Bi 1 Sr,Ca 1 Cu 2 0 I oxide 



for the sample (b) in Fig. 1. 



this ratio, a low-T c phase tends to appear irrespective of 
the sintering conditions. In BiSrCaCu^Qr oxides, the 
oxide of y= 1 is not superconducting. According to the 
results of the X-ray diffraction analyses, the starting 
material corresponding to the composition of 
BiiSriCaiCu 2 Ojr seems to form a single phase. While in 
the nominal composition of oxides with y>2, unreacted 
CuO remained in the sample. A typical X-ray diffraction 
pattern for the oxide of y=2 (sample (b) in Fig. 1) is 
shown in Fig. 3. Although the structure of this oxide is 
not identified yet, it appears to be different from those of 
(LaSrfcCuC^ and YBa 2 Cu 3 0 7 . 

This material having high T e above 105 K may have 
potential application in various industrial fields in the 
near future. It should be noted that these oxides are ex- 
tremely stable in water and moisture and that no change 
in the superconducting properties has been observed even 
after the thermal cyclings between 4 K and room tempera- 
ture or above. 

Furthermore, the oxide has two phases with different 



7* c and their structures seem to be different from those of 
high-r c oxide superconductors discovered up to now. We 
believe that this new oxide will contribute greatly to 
elucidating the high-7" c superconducting mechanism. 

Acknowledgements 
We would like to thank Dr. M. Uehara for the measure- 
ments of magnetization and Dr. K. Ogawa for his useful 



References 

1) J. G. Bednorz and K. A. Muller: Z. Phys. B64 (1986) 189. 

2) S. Uchida, H. Takagi, K. Kitazawa and S. Tanaka: Jpn. J. Appl. 
Phys. 2* (1987) LI. 

3) M. K. Wu, J. R. Ashburn, C. J. Torng, P. H. Hor, R. L. Meng, L. 
Gao, Z. J. Haang, Y. Q. Wang and C. W. Chu: Phys. Rev. Lett. 
58 (1987) 908. 

4) J. Akhnitsu, A. Yamazaki, H. Sawa and H. Fujiki: Jpn. J. Appl. 
Phys. 26 (1987) L2080. 

5) C. Michel, M. Hervieu, M. M. Borel, A. Grandin, F. Deslandes, J. 
Provost and B. Ravean: Z. Phys. B68 (1987) 421. 



BRIEF ATTACHMENT L 



IN THE UNITED STATES PATENT AND TRADEMARK OFFICE 



In re Patent Application of 
Applicants: Bednorzetal. 
Serial No.: 08/479,810 
Filed: June 7, 1995 



Date: March 1, 2005 
Docket: YO987-074BZ 
Group Art Unit: 1751 
Examiner: M. Kopec 



For NEW SUPERCONDUCTIVE COMPOUNDS HAVING HIGH TRANSITION 
TEMPERATURE, METHODS FOR THEIR USE AND PREPARATION 



Commissioner for Patents 
P.O. Box 1450 
Alexandria, VA 22313-1450 



In response to the Office Action dated July 28, 2004, please consider the 
following: 



FIRST SUPPLEMENTAL AMENDMENT 



Sir: 



ATTACHMENT L 



Serial No.: 08/479,810 



Page 1 of 5 



Docket: YO987-074BZ 



LETTERS T@ Nt^OSIE 



® 



The resulting map (Fig. le) shows that the absorption feature 
has a mean W of 0.2 nm and stretches from roughly north to 
south across the entire emission line region, corresponding to 
a length of >30 kpc (the map presents only the area with good 
signal-to-noise ratio). Its spatial width is rather uncertain, 
because it is unresolved in the east-west direction (<1.5"). It 
cannot be narrower than 0.5" because otherwise even a 100% 
obscuration would be washed out by our beam into a relative 
depression of <25% (0.25 nm). So we assume a projected size 
or lOx 10 kpc 2 for the absorber, with a deconvoluted equivalent 
width or about 0.5 nm. 

Such an absorber can either consist of one or more clouds 
located well in front of 4C41.17 (if the blueshift of the absorption 
is cosmological, the absorber sits at a comoving distance of 
5 Mpc). On the other hand, the velocity in the EELR itself is 
large enough to cover this blueshift; otherwise we would be 
unable to detect the feature. Thus, a dense, partially ionized 
cloud at the edge of 4C41.17 could equally explain the absorp- 
tion. In this latter case more detailed observations are necessary 
for a physical interpretation. We therefore would like to pursue 
the former possibility of a physically separated absorber. Such 
clouds — commonly known as Lyman-forest clouds — and their 
properties have been extensively studied in the absorption line 
spectra of high redshift quasars. 

For comparison we make use of a spectrum 14 of the quasar 
QOOOO-263 (z = 4.11), the Lyman-forest of which covers the A 
range of our observation. We smoothed the original spectrum 
(resolution, 0.1 nm) to our instrumental resolution of 1.0 nm. 
The comparison between smoothed and original spectrum 
reveals that any absorption feature as deep as that observed in 
4C41.17 typically consists of two or more narrow absorption 
lines. We have to realize therefore, that our 'absorption cloud' 
is likely to be a superposition of several individual Lyman-forest 
clouds. Nevertheless, we believe that the outline of the absorber 
in the W map (Rg. le) is most likely to be determined by one 
single cloud which made the feature strong enough to become 
detectable, and we assign half of the measured equivalent width 
(0.25 nm) to this cloud. Assuming a Doppler parameter 6 = 
35kms _1 and N H JN Ha = 10 -4 as typical for Lyman clouds of 
that depth (refs 1, 3), we find a column density N H , ~ 10" cm - *. 
A cigar-shaped cloud of 40 kpc length and 10 kpc diameter 
would contain a total hydrogen mass of -3 x 10 7 M Q . 

What is the probability of detecting such an absorption feature 
in front of 4C41.17? Both the smoothed spectrum of Q0000-263 
(ref. 14) and the standard dN(W, z)/dz relation 15 yield -25 
features with W>0.4 nm on each line of sight and within one 
z unit at the observed wavelength. Considering the 'useful' 
wavelength range of -1.2 nm (the blue half of the width of the 
emission line) in our search for line features, and the area of 
the EELR inspected of -20 arcsec 2 , the probability of detecting 
a cloud of a typical size of a few arcsec 2 is close to 1. 

In conclusion, we believe that we have succeeded in obtaining 
the first direct observation of a Lyman absorption cloud. Either 
this cloud belongs directly to the mass concentration around 
4C41.17 or it is a physically separated foreground object. In the 
latter case it would represent the population of Lyman-forest 
clouds known from the absorption spectra of quasars. In either 
case, our observations indicate that the relevant absorbers 
have projected sizes of some 100 kpc 2 and an elongated shape, 
like a cigar or a sheet seen almost edge-on in the case of 
4C41.17. D 





^oop®ir^0udloji(c8oviifty Stfl K 

S. N. PtaMta^t, E. V. Antopov*, O. Oimailsseimt 

* Chemical Department Moscow State University. 
119899 Moscow. Russia 

t Laboratoire de CristallograpWe CNRS-UJF, BP 166. 
38042 Grenoble Cedex 09, France 

t AT&T Bell Laboratories. Murray Hill. New Jersey 07974, USA 



Following the discovery 1 of high-transition-temperature (hlgh- 
TJ superconductivity in doped LajCuO^, several families of 
related compounds have been discovered which have layers of Cu0 2 
as the essential requirement for superconductivity: the highest 
transition temperatures so far have been found for thallium- 
bearing compounds 1 . Recently the mercury-bearing compound 
HgBajRCujO^, (Hg-1212) was synthesized 3 (where R is a rare- 
earth element), with a structure similar to the thallium-bearing 
superconductor TlBa 2 CaCu 2 0 7 (Tl- 1 2 12), which has one TIO layer 
and two CuO, layers per unit cell, and a T, of 85 K (ref. 2). Bat 
in spite of its resemblance to Tl-1212, Hg-1212 was found not to 
be superconducting. Here we report the synthesis of the related 
compound HgBa 2 Cu0 4+4 (Hg-1201), with only one Cu0 2 layer 
per unit cell, and show that it is superconducting below 94 K. Its 
structure is similar to that of Tl-1201 (which has a 7", of < 10 K) 4 , 
but its transition temperature is considerably higher. The availabil- 
ity or a material with high T t but only a single metal oxide (HgO) 
layer may be important for technological applications, as it seems 
that a smaller spacing between Cu0 2 planes leads to better super- 
conducting properties in a magnetic field 1 . 

The samples were prepared by solid state reaction between 
stoichiometric mixtures of Ba 2 CuO J+ , and yellow HgO (98% 
purity, Aldrich). The precursor Ba 2 Cu0 3+4 was obtained by the 
same type of reaction between Ba0 2 (95% purity, Aldrich) and 
CuO (NormaPur, Prolabo) at 930 °C in oxygen, according to 
the procedure described by De Leeuw el aL 6 . The powders were 
ground in an agate mortar and placed in silica tubes. All these 
operations were carried out in a dry box. After evacuation, the 
tubes were sealed, placed in steel containers, as described in 
ref. 3, and heated for 5 h to reach -800 "C. The samples were 
then cooled in the furnace, reaching room temperature after 
-10 h. 

The formation of the new phase HgBa 2 Cu0 4< . 4 was revealed 
by X-ray powder analysis, performed with a Guinier-Hagg 
focusing camera and Fe Ka radiation (1.93730 A). Finely pow- 
dered silicon (a = 5.43088 A at 25 °C) was used as an internal 
standard. The intensities of the reflections were evaluated by 
means of an automatic film scanner and indexed on a tetragonal 
cell with lattice parameters a = 3.8797 (5) A, c = 9.509 (2) A and 
assignment Z=l. No systematic absences were observed, 
leading to the number of molecules per unit cell of the space 
group PA/mmm. The c parameter corresponded to the value 
calculated from the formula c = 9.5+3.2(n- 1), similar to that 
deduced for the TIBa 2 R„_ 1 Cu„0 2 „ H .j homologous series. We 
took this as a strong indication that the powder pattern corres- 
ponded to that of the first member of the HgBa 2 R„.,Cu„0 2 „ +2+i! 
series. 



NATURE ■ VOL 362 • 18 MARCH 1993 



Otters to nature 




r(K) 

FIG. 1 AC magnetic susceptibility x (a) and normalized resistivity (fa) as a 
function of temperature for HgBajCuO.,.,,. 



Scanning electron microscopy using a JEOL SM 840A equip- 
ped with an energy-dispersive spectroscopy (EDS) attachment 
revealed that the sample was well crystallized with particle sizes 
of several micrometres. EDS analysis of several well crystallized, 
flat and oriented grains was performed. Beside Hg, Ba, Cu and 
O, no other element was detected in the spectra. The average 
metal ratio found for eight grains was Hg:Ba:Cu = 
28(1 ):47(2): 25(1), where the numbers between parentheses are 
the standard deviations. Determination of the oxygen content 
by EDS analysis was not possible, so it was estimated by struc- 
tural analysis and iodometric titration. The cation stoichiometry 
is in qualitatively good agreement with the proposed formula 
of the new compound. 

Alternating-current magnetic susceptibility measurements 
between 4.2 and 120 K, done without any additional oxygen 
treatment, showed that HgBa 2 CuO«+ s samples undergo a transi- 
tion from paramagnetic to diamagnetic with an onset as high 
as 94 K (Fig. la, where the susceptibility is in electromagnetic 
units g~'). The estimated magnetic susceptibility at 4.2 K. corres- 
ponds to >50% of the ideal diamagnetic values. 

The resistivity was measured between 4.2 and 250 K by the 
four-probe technique. The sample was a pressed pellet which 
was annealed in oxygen for 2 h. The temperature dependence 
of the normalized resistivity, shown in Fig. 1, exhibits a sharp 
drop at T c , but the transition is broad and it reaches the value 
of zero resistance only at 35 K. This behaviour indicates that 
the sample is not homogeneous. 

To determine the structure of HgBa 2 Cu0 4+s , X-ray powder 
data were collected by a 0/20 STAD1 P diffractometer in trans- 
mission mode. The experimental conditions were as follows: 20 
range =6-115° (0.02° steps) with fixed counting time 60s and 
a rotating sample. An absorption correction was applied and 
the sample thickness was calculated from the primary beam 
absorption (nR = l.l, where is absorption coefficient and R 
is thickness). The structural refinements were done by the Riet- 
veld method. The initial positional parameters were deduced 
from a structural model containing the sequence (Hg)(BaO)- 
(Cu0 2 )(BaO)(Hg). After convergence (intensity discrepancy 
factor, J?, = 0.039), a Fourier difference map revealed that the 
position at (j.i, 0) of the Hg layer was partially occupied. 
During the final cycle of refinement, the occupancy factor of a 
third oxygen atom placed in this position was varied together 
with the positional and thermal parameters for all atoms (except 
for the thermal parameter of 0(3) which was kept fixed at 
1.0 A 2 ). The final intensity (R,) and profile (R t ) discrepancy 
factors based on 84 reflections were R, = 0.0367 and R p = 0.1 16, 
with a GOF (goodness of fit) = 0.33. 

The final positional and thermal parameters together with the 
relevant interatomic distances are given in Table 1. Observed, 
calculated and difference diffraction patterns are shown in 
Fig. 2. A schematic representation of the structure is shown in 
Fig. 3. Preliminary structural refinements based on powder 
neutron diffraction data support the presence of oxygen in the 
0(3) position with an occupancy factor slightly larger than that 
found by X-ray powder diffraction data. The neutron data also 
NATURE • VOL 362 • 18 MARCH 1993 



TABLE 1 Ciystallographlc data for Hg8ajCuO«», 



Positional, thermal and occupancy parameters 



Atom Posmc 








fc^aotA 2 ) Occupancy 






0 






Ba 2h 


OS 


0.5 


02979(1) 


1.43(4) LOO 


Cu lb 


0 




OS 


0.88(9) 1.00 


0(1) 2e 


0.5 


0 


OS 




0(2) 2g 


0 


0 


0206(2) 


22(3) L00 


0(31 lc 


0.5 


OS 


0 


U0 0.10(3) 




1.95(2) 


(A) 

Cu-0(1)( 


<4) L9400J 


Ba-0(JJ (X4) 2.730(1) 






Cu-CX2) (X2) 2.79(2) 


Ba-0(2)(x4> Z880{5) 










Ba-OOr* 2.831(1) 


Data obtained 






CuKoti radiatk) 


n<A-l_54056 A), giving 8« 


a8776«4)A.c 


=f K>73<1) K 









• Partially occupied sites. 



confirm the large value for the mercury thermal factors. As in 
the case of the X-ray data, the anisotropic model shows a very 
slight difference between B,, = B 22 and B n , the thermal factors 
along x, y and z respectively. 

HgBa 2 CuO, +a has a structure related to that of Hg-1212 
(ref. 3). Its lattice parameters correspond to four-layered packing 
along the c-axis of a unit cell: a = , c = la^., (where a^. 
is the parameter of the perovskite subcell) and its structure 
contains the sequence (CuO 2 )(Ba0)(HgO„)(BaO)(Cu0 2 ). The 
Cu cations are octahedrally coordinated, while the coordination 
of the other cations depends upon the value of & This, as 
obtained from powder X-ray data, is 0.10(3). An important 
consequence is that most of the Hg cations have two oxygen 
atoms near them in a 'dumb-bell' configuration, an appropriate 
coordination for Hg 2 * cations. Because 8 is small and different 
from zero (within about three standard deviations) X-ray powder 
data alone are insufficient to determine which sites of the rock- 
salt positions in the HgO layer are occupied and how they affect 
the Hg coordination. The extra oxygen atoms are needed in 
order to increase the average oxidation number of the Cu and 
to create the concentration of holes necessary for superconduc- 
tivity. Iodometric titration performed with a large excess of KI 
leads to 16% of Cu 3+ , corresponding to 5 = 0.08. 

Similarly, the structure of HgBa 2 RCu 2 0»+ 4 (the second mem- 
ber of the HgBa 2 R„_,Cu„0 2 „ +2+ j series) can be described as 
six-layered blocks made of rock-salt and perovskite-type struc- 
tures. In the structure of Hg-1212 the layer sequence is: 

(Ba0)(HgO,)(BaO)(Cu0 2 )(R)(CuO 2 )(Ba0)(Hg0,)(Ba0) 
rock-salt perovskite rock-salt 

The Cu0 2 monolayer in Hg-1201 has been replaced by the 
(Cu0 2 )(R)(Cu0 2 ) block. As a consequence the Cu cations are 



a 

Li 


• ll UllL « I..L. _ 


1 b 1 


II II 


Illl llll 1 11 II 11 11 1 


ii mil ii iii iMiiiiiimi iiii mil 


c ' 1 



TO. 2 Observed (a), calculated (b) and difference (c) powder patterns after 
Rietveld refinement for HgBajCuO,,*,. 

227 



LETTERS TO NATURE 





Dependence of aggregate 
morphology on structure 
of dimeric surfactants 



R. Zana* & Y. Talmon 



a Technion-lsrael Institute of 



FIG 3 Structure of HgBa,Cu<W The large, r-~~~- -■ 

reoresent the Ba, Hg and O atoms, respectively. The Cu atoms are v 
S^a^tTthat the partially occupied oxygen 0(3) site on the Hg 
layer Is represented by a partially filled circle. 



pyramidally coordinated. The coordination of the Ba and Hg 
cations in Hg-1212 is similar to that of the same cations m 
Hg-1201. The R cations are surrounded by 8 oxygen atoms 
arranged as a prism. The valence of the Cu ««>oiii depend, 
upon the value of 8 and the valence of the R cations, if the 
same Cu valence or hole concentration as in Hg-1201 .s needed 
to induce the superconducting state in Hg-1212, then the R 
cations should be 2+ and B m2 should be appreciably greater 
than 5 l201 . For the previously reported Hg-1212, R. was a mixture 
of Eu and Ca, and 6 was not precisely determined . It is possible 
that & was not large enough to compensate for the higher valence 
of the R cations and to transfer the needed extra charges to 
CuO, layers. «■ u n >~ n 

As stated above, the structural arrangment of HgBa 2 CuU*+« 
is similar to that of TlBa 2 Cu0 5 - 8 . except for the oxygen 
stoichiometry of the HgO. and TO,., layers respectively. For 
the former, 5 is very small and this depletion is possible because 
the dumb-bell coordination is appropriate for the Hg cations. 
For the latter, the T10,., layer is only slightly oxygen depleted, 
creating the appropriate coordination for the thallium cations, 
resulting in either a distorted octahedron or a five-coordinated 
polyhedron. These different requirements for attaining the 
optimal concentration of holes are due to the different preferred 
coordination geometries of the TP* and Hg 2 cations. 

The first member of the latter series (T1-1201) has been repor- 
ted and found to become superconducting at <10 K. (ret. 4) By 
doping the Ba sites with La this value can be increased to 52 K. 
(ref 7). The second member of the mono-Tl series becomes 
superconducting at 85 K (ref. 2). This increase is a general rule 
for the first few members of this series of compounds. If this 
behaviour holds for the Hg-series, the second member could 
reach values for T c as high as those of the thallium. 

The possible advantages for technical applications of 
HBBa,Cu0 4+s , in analogy with one-Tl-layer materials, would 
be due to the relatively short distance between CuO, layers. 
This might lead to lower anisotropy of the superconducting 
properties and to higher flux-melting temperatures than those 
of two-TlO-layer superconductors 5 . u 



Surfactant molecules in water form organized assemblies of 
various shapes, such as micelles and bUayer lamellae, which are 
of interest aVanalogi.es of biological structures, as mode .systems 
for studying complex phase behaviour and because of their techno- 
importance, for example to the food and P-UJM. 
The polar head groups are usually arranged randomly at the 
2rf£ .ff these Leslies. We have studied the effetf on he 
microfracture of these assemblies of imposing constraints on the 
head-group spacing. We investigate the structures formed by 
•doable-beaded' surfactants in which two quaternary 
spedes (C.H^^N^CHjW are linked at the level of the head 
g ™J iya Mrocarbon spacer <C,H„). Here we Report the 
microstructures formed by these dimeric surfactants with m - 12 
3 or 4 in aqneo us solution, b, rapidly cooling the micellar 
solutions and investigating the vitrified 

electron microscopy. The surfactants with a short spacer <> - 2, 3) 
form long, thread-like and entangled micelles even at low con- 
centrations, whereas the corresponding monomelic ammonium sur- 
factants can form only spherical micelles. The dimenc surfactants 
with s=4 form spheroidal micelles. Thus short spacers (which 
impose reduced head-group separation) appear to promote lower 
spontaneous curvature in the assemblies. This approach may afford 
a new way to control amphiphile self-aggregation. 

Conventional surfactant molecules generally comprise two 
distinct parts that are incompatible with each other: on polar 
head and either one or two alkyl chains. These mo e extend 
to self-associate in watex, where they produce micellar solutions 
in the dilute range, and lyotropic mesophases at higher con- 
centrations. Whatever the structure, the surfactant polar head> 
are located at the interface between the hydrocarbon and water 
regions. Their relative positions and distances are determined 
mainly by their electrostatic interactions, and also by the packing 
requirements of the disordered alkyl chains" 3 . In ca mm o 
rubidium soaps at low temperature in the presence of water, for 
example the head groups form well developed hexagonal or 
rectangular crystalline arrays 4 . Generally, however, they are 
arranged randomly, and little is known of their packing geometry 
or the width of their spacing distribution. 

To investigate the effect of a perturbation of the local arrange 
ment of polar heads on the micellar and mesomorphic properties 



NATURE • VOL 362 • 18 MARCH 1993 j 



BRIEF ATTACHMENT M 



IN THE UNITED STATES PATENT AND TRADEMARK OFFICE 



In re Patent Application of 
Applicants: Bednorz et al. 
Serial No.: 08/479,810 
Filed: June 7, 1995 



Group Art Unit: 1751 
Examiner M. Kopec 



Date: March 1,2005 



Docket: YO987-074BZ 



For. NEW SUPERCONDUCTIVE COMPOUNDS HAVING HIGH TRANSITION 
TEMPERATURE, METHODS FOR THEIR USE AND PREPARATION 



Commissioner for Patents 

P.O. Box 1450 

Alexandria, VA 22313-1450 



In response to the Office Action dated July 28, 2004, please consider the 
following: 



FIRST SUPPLEMENTAL AMENDMENT 



Sir. 



ATTACHMENT M 



Serial No.: 08/479,810 



Page 1 of 5 



Docket: YO987-074BZ 



NATURE VOL 336 17 NOVEMBER 1988 



Superconductivity near 70 K in a new family of 
layered copper oxides 

R. J. Cava, B. Batlogg, J. J. Krajewski, L. W. Rnpp, L. F. Schneemeyer, T. Siegrist, 
R. B. vanDover, P. Marsh, W. F. Peck, Jr, P. K. GaUagher, S. H. Glanim, J. H. Marshall, 
R. C. Farrow, J. V. Waszczak, R. Hull & P. Trevor 

AT&T Bell Laboratories, Murray Hill, New Jersey 07974, USA 



A new family of high-temperature superconductors is described, with the general formula Pb2Sr 2 ACu 3 O t +s. Although they 
have the planes of CuO s square pyramids characteristic of the other copper-oxide superconductors, the new compounds 
belong to a distinct structural series, with wide scope for elemental substitution. Their unusual electronic configuration also 
gives new insight into the role of charge distribution among the structural building blocks in controlling superconductivity. 



Since the first observation' of high-transition-temperature 
(high- 1;) superconductivity in La-Ba-Cu-O, progress in the 
understanding of this remarkable phenomenon has been cou- 
pled to the discovery of new materials. Until now, three families 
of copper-oxide-based high-T e superconductors have been 
identified, based on (La,M) 2 Cu0 4l LnBajCujO,, and 
(Tl.BiJ 0 ,(Ba,Sr)jCa e+I Cu«0 1B+2) , + , (ref. 2). (Here M represents 
1 metal cation that may substitute on some La sites, and Ln 
represents a lanthanide.) Here we report the discovery of a new 
family of planar copper-oxide superconductors with general 
formula Pb 2 Sr 2 ACu,O a +« (where A is a lanthanide or a mixture 
of Ln+Sr or Ca), and describe the synthesis, crystal structure 
tnd properties of prototype compounds. We find, for example, 
that one preliminary optimal composition Pb,Sr 2 YojCao.sCuj08 
has a superconducting T e of 68 K. The new family displays the 
tame kind of rich substitutional chemistry as is observed for 
LnBa 2 Cu,0 7 , with the phase forming for Y and at least La, Pr, 
Nd. Sm, Eu, Gd, Dy, Ho, Tm, Yb and La, spanning the entire 
rare-earth series. Wide ranges of large-metal-atom solid solution 
ind oxygen stoichiometry are observed, suggesting many poss- 
ible avenues to be explored for the optimization of supercon- 
ducting properties. 

Superconductivity is induced in the host compounds 
Pb^SrjLnCujOj+j (5«=0) either by partial substitution of a 
divalent ion (such as Sr or Ca) on the lanthanide site, or possibly 
by the accommodation of excess oxygen (« > 0), or a combina- 
tion of both. The compounds can be synthesized only under 
mildly reducing conditions, which are necessary to maintain Pb 
in a 2+ oxidation state. Oxidation of 5 = 0 compounds is poss- 
b\e. but only at low temperatures, where decomposition to a 
PMtvJ-containing perovskite is sluggish. Remarkably, the for- 
nal average oxidation state of copper in the superconductors 
b, less thin 2+, but a clear structural distinction between 
different types of copper layers leads us to hypothesize that 
holes are nonetheless present on electronically active CuO 
pyramidal planes. 

Synthesis 

The preparative conditions for the new materials are consider- 
sWy more stringent than for the previously known copper-based 
superconductors. Direct synthesis of members of this family by 
reaction of the component metal oxides or carbonates in air or 
oxygen at temperatures below 900 "C is not possible because of 
the stability of the oxidized SrPbOj-based perovskite. Successful 
synthesis is accomplished by the reaction of PbO with pre- 
reacted (Sr, Ca, Ln) oxide precursors. The precursors are pre- 
pared from oxides and carbonates in the appropriate metal 
ratios, calcined for 16 hours (in dense A1,0 3 crucibles) at 920- 
980% in air with one intermediate iding. Some of the 



PbjSr 2 LnCu 3 0 8+a compounds can be prepared in air from 
PbO+LnSr 2 Cu 3 0, precursor mixtures, which are not reacted 
at temperatures below ~850°C. For example, single-phase 
PbjSr 2 YCujO, + g (5 =0) can be prepared by reacting PbO with 
YSr 2 Cu 3 O x at 920 °C for 1 h, followed by quenching. Slower 
cooling results in partial decomposition through oxidation. 
Short reaction times are generally sufficient to obtain single- 
phase products. The same air-heating/quenching process does 
not appear to work, however, for Pb^SijLaCujOs+s or 
PbjSriLuCujOs+j. 

The best synthetic conditions found so far involve the reaction 
of PbO with the cuprate precursors in thoroughly mixed pressed 
pellets. Reaction temperatures are between 860 and 925 °C, for 
times between 1-16 hi, in a flowing gas stream of 1% 0 2 in N 2 , 
a mildly reducing atmosphere. For Pb 2 Sr 2 Y,_.iCa x Cu 3 0 8 . M , for 
example, single-phase materials are obtained for 0^x<0.5 in 
1% 0 2 after heating overnight at 865 "C and cooling in the gas 
stream to room temperature in 15 minutes. Using higher tern- 
peratues, higher Po^ in the gas stream or higher Ca contents of 
the starting mixture results in the intergrowth of 123 -type 
YSr 2 (Pb,Cu)jO x with the new compound, or the formation of 
an SrPbO}-based second phase. Similar procedures are success- 
ful for other Sr/rare-earth/Ca combinations. The oxygen con- 
tents of Pb^Y^CaxCujOj+j fdr0=£xs0.50, prepared under 
these conditions, are measured by reduction in H 2 and are 
uniformly 6=0±0.1. Ca is employed as a dopant on the Ln 
site because it has an ionic size similar to the intermediate 
rare-earths. We have not yet found synthetic conditions under 
which PbiSrj+jLn^xCusOt+a solid solutions can be prepared 
as single-phase polycrystalline samples that are good bulk super- 
conductors, although superconducting single crystals of that 
stoichiometry have been prepared- 
Single crystals of the superconducting compounds were grown 
from PbO- and CuO-rich melts using a similar precursor tech- 
nique. Melt compositions were generally Pb 3 .5Sr J YCu 4 O x . Fol- 
lowing a 30-min soak at 1,025 "C, samples were cooled at 2°C 
rain" 1 in the 1% 0 2 atmosphere to temperatures between 800 
and 400 °C, and were then rapidly cooled to room temperature 
in the same gas stream. Crystals are plate-like in habit, but are 
generally more equiaxed than those of LnBa 2 Cuj07. 

Stoichiometry and crystal structure 

Compounds of stoichiometry PbjSrjLnCujOg (5=0). are not 
bulk superconductors, although. we often observe small amounts 
of superconductivity (1% or less) in materials of that 
stoichiometry prepared either by the quench or by the l%-0 2 
synthetic techniques. The non-bulk superconductivity may be 
due to inhomogeneitjes in either oxygen content or Sr/Ln distri- 
bution. 



-ARTICLES— 



NATURE VOL 3*S 17 NOVEMBER 19 



Fig.1 Two representations of the crystal struc- 
ture for the new superconducting compounds, 
for the case of PbjSr^NdawOijOj+a. Rep- 
resentation a emphasizes the Cu-O and Pb-O 
bonding scheme, and representation b empha- 
sizes the manner in which Cu-0 and Pb-O 
coordination polyhedra are arranged. 




The range of oxygen contents possible for these compounds 
is remarkable. Pb 2 Sr I YCu 3 08 + ,, 5=0, for example, can be 
oxidized by heating in 0 2 to temperatures below 500 "C for short 
times (2-4 h) to 8 values of - 1.6, retaining the same basic crystal 
structure. We have observed values as large as A" = 1.8 for 
Pb 2 Sr a Ya 7 5Ca 0 . 2J Cu,Og +s . Oxidation at temperatures higher 
than 500 °C, or for longer reaction periods, generally results in 
decomposition to the SrPbO,-based perovskite. Powder samples 
of PbjS^YCuA+a with large values of * are not superconduct- 
ing. Single crystals of the Pb 2 Sr I+ »Ln x CujO, + , type are super- 
conductors with transition temperatures between 10 and 70 K. 
These crystals may have non-zero values of 8 but have not yet 
been fully characterized. The range of observed suggests a 
complex and interesting relationship between T c , 8 and the 
SnLn ratio. 

Powder X-ray difiraction indicates that the new phases have 
an orthorhombic unit cell which is based on a many-layer 
perovskite structure. The characteristic X-ray pattern for the 
prototype compound PbjSrjYCujO, is presented in Table 1. 
The compound deviates only slightly from tetragonal symmetry. 
The simplest cell consistent with the X-ray pattern is c-centred, 
with lattice parameters o « 5.40, b » 5.43, and e «= 15.74 A. Sys- 
tematic absences are consistent with a c-centred cell down to 
the detectability limit of 1% maximum intensity. The orthorhom- 
bic cell gives an excellent fit to the powder difiraction pattern 
but a hint of a shoulder on the high 20 side of the 314 reflection 
indicates that the true symmetry may be weakly monodinic. 
Although the lattice parameters for this family of compounds 
are very similar to those reported for TlBajCaaCujOg (ref. 3), 
the crystal structures are quite difierent Electron microscope 
investigations indicate that for some crystals, weak (but sharp) 
reflections are present which violate the e-ceatring. Furthermore, 
these studies show the presence of long-period, long-range- 
ordered superlattices in the a~b plane, suggesting that a variety 
of structural distortions andstolchiomef^'-driven atom-ordering 
; schemes can occur. 



The crystal structure of compounds in this family, determined 
for a superconducting Nd-based single crystal of approximate 
stoichiometry Pb 2 Sr ZJ4 Nd 0 .76CujOg +4 (determined by structure 
refinement) is shown in Fig. 1. The crystal employed in the 
structural determination was twinned, as expected from the 
pseudo-tetragonal symmetry. The atomic coordinates are repor- 
ted in the c-centred orthorhombic cell to be consistent with the 
powder data, but a primitive cell with a and b rotated by 45* 
and reduced by -Jl gives an equally good description of the 
single-crystal data. The very small scattering cross-section of 
oxygen precludes determination of 5 by refinement The date 
are well fitted by the structural model (refinement parameter 
R =3.7%), but a microscopic explanation of the orthorhombic 
symmetry is not apparent; if the origin is primarily in the oxygen 
sublattice we would not be able to detect it in the X-ray structure 
determination. 

The basis of the structure comprises infinite planes of comer- 
shared CuOj pyramids separated by eight-coordinate rare-earth 
atoms, as are common to all the presently known copper-based 
superconductors with T C >50K- The four in-plane copper- 
oxygen distances are ~1.9 A, and the distance to the apical 
oxygen is ~23A, both of which are very similar to those 
observed in YBa 2 Cuj0 7 . The structural components unique to 
the new class of materials are the PbO-Cu0 4 -PbO planes shown 
in the centre of the Fig. h For 8 = 0, Pb has a distorted flattened 
square pyramid coordination (sharing : edges with adjacent 
pyramids), with the lone pair pointing toward the vacant sixth 
site of the coordination octahedron^ The PbO s pyramids are 
separated "by a single copper layer, which, for «=0, is oxygen- 
free, and displays an O-Cu-O coordination, characteristic of 
Gu' + (Cu-O distance ~1.8 A), as is observed in non-supercon- 
ducting YBa 2 Cu 3 0« . During the low-temperature oxidation pro- 
cess, oxygen is apparently accommodated in this copper layer, 
resulting in a large expansion of the c axis. The PbO s and CuO$ 
pyramidal planes are joined by the common oxygens' at their 
apices. The Sr atoms an irdinated to nine oxygens, as in (La, 



NATURE VOL 336 17 NOVEMBER 1988 



-ARTICLES- 



t i r 




0 20 40 60 80 

Temperature (K) 



Fig. 2 Magnetization data (dx. field-cooled at 25 Oe) for 
PbiS^YojCaojCujO, . 



Sr)Cu0 4 , and the Ln site is eight-coordinate, as in the 
LnBa 2 Cu 3 0 7 family, sandwiched between the Cu0 5 pyra- 
midal planes. In the superconducting compound 
PbjSrjY^^Ca^CujOj+a, Ca partiaUy substitutes for Y in the 
eight-coordinate site. 

The crystal, structures of all the known copper-oxide-based 
superconductors are generally described as many-layered perov- 
skites. The similarities and differences among them are most 
easily illustrated in terms of the stacking sequences of rocksalt- 
like (AO) and perovskite-like (B0 2 ) layers 2 . Taking, for example, 
representatives from the superconductor families that have 
double CuO s pyramidal layers, the .stacking sequences are: 
Pb 2 Sr 2 (Y,Ca)Cu 3 0 8+ , 

-(Y, CaJ-CuOi-SrO-PbO-CuO^PbO-SrO-CuOj-CY, Ca)- 
Tl 2 Ba 2 CaCu 2 0g 

-Ca-CuOj-BaO-TlO-TiO-BaO-CuOr-Ca- 
YBajCujOM., 

-Y-CuOj-BaO-CuOg-BaO-CuOr-Y- 



Table 1 Characteristic X-ray powder diffraction pattern for 
PbjSriYQijO, 



hkl 


A 


///„ 


hid 


d 


Uh 


001 


15.74 


7 


U6 


2.164 


11 


002 


7.87 


3 


025 


1057 


12 


003 


5.25 


2 


205 


1050 


10 


004 


. 3.94 


10 


008 


1.967 


7 


iio 


3.831 


11 


220 


. 1.915 


25 


■in 


3.722 


24 


118,009 


1.750 


2 


112 


. 3.444 


1 


027.207 


1.730 


1 


.005 


3.148 


11 


224 


1.722 


2 


113 


3.094 


11 


130 


1.717 


2 


114 


1745 


100 


310, 131 


1.708 


3 


020 


2.717 


43 


311 


1.699 


2 


200 


2.701 


43 


225 


1.636 


3 


021 


1677 


7 


133 


1.632 


3 


201 


1662 


7 


313 


1.625 


1 


006 


2.623 


6 


028 


1.593 


11 


023 


1412 


1 


208,119 


1.591 


11 


203 


1401 


1 


134 


1.574 


18 


024 


1236 


2 


314 


1.568 


14 


204 


1227 









C", Ka radiation, 0-60° 29 c-centred orthorhorabic cell, preliminary 
indexing, true symmetry may be weakly monoclinic Lattice parameters 
tt =5.4019(15), 6 = 5.4333(15), c = 15.7388r . 



The new superconductors, then, can be seen to be intimately 
related in structure to those previously described. They can be 
considered as related to Tl 2 Ba 2 CaCu,0 8 by insertion of a single 
CuO s layer between adjacent polarizable AO layers, or related 
to YBa 2 Cu J 0 6+ g by sandwiching of the CuO s 'chain' layer by 
two PbO layers. We believe that it is the electronic screening of 
the Cu0 2 planes from the CuOg layers by the PbO layers that 
makes the new superconductors of considerable interest. Fur- 
thermore, we expect these materials to be even more anisotropic 
in their physical properties than those previously known, as 
the double pyramidal CuO z -A-Cu0 2 layers are widely 
separated. 

Superconducting properties 

We have studied the composition dependence of the supercon- 
ducting properties of compounds in the series 
PbjS^Y^Ca^CujOg for 0£x£0.75, by estimating the flux 
expulsion measured on cooling in a field of 25 Oe in a d.c. 
SQUID magnetometer (S.H.E. model 905). The greatest flux 
expulsion occurs for x = 0J, and is ~20% of the ideal value 
(see Fig. 2). Because flux becomes trapped in the pores of these 
low-density ceramics, this is an underestimate of the true volume 
fraction of superconductivity; For xs=0.5, the materials were 
not entirely single-phase, with one or more impurity peaks 
having a maximum intensity of 5% of the strongest peak in the 
powder X-ray pattern. This, coupled with the estimate of the 
volume fraction of superconductivity, suggests that the optimal 
superconducting composition may have x somewhat greater 
than 0.5. This could be achieved if different synthetic methods 
can be found that allow a larger range of solid solution to be 
attained. We have measured the normal-state susceptibility (in 
a 20-kOe field) for temperatures below 400 K of apparently 
single-phase samples (no unindexed X-ray lines to 0.5% 
maximum intensity) of the non-superconducting endmember 
Pb 2 Sr 2 YCu 3 O g and superconducting Pb^Yo^Cao^CusOg. 
The susceptibility of the superconductor (*) is essentially tem- 
perature independent (^"lxlO" 4 cm.u. per mole formula 
unit), with only a slight decrease at low temperatures. This 
temperature dependence is similar to that of high-quality 
YBa 2 Cu 3 0 7 , and is characterized by the absence of a. Curie- 
Weiss contribution. Furthermore, this supports our conclusion 
that the copper atoms between the PbO layers are Cu ,+ . Post- 
oxidation at 500 °C results in oxidation of this copper to mag- 
netic Cu i+ . Pb 2 Sr 2 YCu 3 O a appears to be magnetic (-0.5 u,B per 
Cu atom), but further studies are necessary to clarify whether 
this is intrinsic or is due to the presence of highly magnetic 
impurity phases that are undetectable by X-ray diffraction. 

Figure 3 shows the temperature dependence of the resistivity 
for a single crystal of Pb 2 Sr 2 Dy l _ Jt Ca»Cu J Og + g. The midpoint 
of the superconducting transition is at 51.5 K (indicated by an 
arrow in Fig. 3), although there is a small foot which gives 
a zero-resistance T e of 46 K. Above T e the temperature 



Table 2 Crystallographic data for PbjSr 2 > ( Nd (1 , 76 CujO, 



Atom 


Position 


X 


y 






Fb 


41 


1/2 


0 


038858(4) 


1.09(2) 


Sr 


4k 


0 


0 


0.22184(9) 


0.74 (4) 


Nd,Sr* 


2a 


0 


0 


0 


0.69 (3) 


Cul 


2d 


0 


0 


1/2 


0.86(9) 


Cu2 


41 


1/2 


0 


0.11074(13) 


0.46 (5). 


01 


41 


1/2 


0 


0.2546(8) 


1.5(5) 


02 


4k 


0 


0 


0.384(3) 


13(5) 


63 


8m. 


1/4 


1/4 


0.0995(5). 


0.9(3) 



Orthorhombic cell (pseudotetragonal substructure); «=5.435(1)A, 
6=5.463(1)A, c = 15.817(3)A; space group Cmmm, r=2; observed 
reflections 707, /?. = 0.037. 

• Mixed occupancy site: (l) Sr, 0.76(1) Nd. 



-AR1TCLES-- 



NATURE VOL. 336 17 NOVEMBER 1988 




Temperature IK] 



dependence is fairly linear, but near T c there is a region of 
positive curvature which, along with the resistivity foot, we 
- ! ^-s in the metal and/or oxygen 



distribution. The scale of the resistivity is a factor of ten greater 
than for previous oxide superconductors.. It is not yet dear 
whether this is an intrinsic property. 

A typical resistivity curve for a ceramics sample is shown in 
the inset to Fig. 3, illustrating the typically broad transitions 
observed. The transition in this sample begins at 79 K (arrow) 
but zero resistance is achieved (within instrumental accuracy) 
as 32 K. Note that the resistivity scale is again quite high. We 
attribute the breadth of the transition and the negative normal- 
state temperature coefficient to inhomogeneity in . the metal 
and/or oxygen distribution, rather than to exogenous phases at 
the grain boundaries. The behaviour of this system seems to be 
very similar to that of (La,Sr) 2 Cu0 4 (ref. 4). 

Electronic aspects 

Given that the average formal copper valence of previously 
known superconductors has always been greater than +2, the 
new superconductors are unique and, at first sight, anomalous. 
For the series PbjSrjYt^Ca^CujOg, the average formal copper 
valence increases from 1.67 in the non-superconducting x = 0 
member to -1.92 at the maximum Ca concentration studied. 
At our current estimate of the optimal superconducting composi- 
tion (x = 0.5), the average formal valence is 1.83. The linear 
coordination of the copper atom sandwiched between the PbO 
sheets, characteristic of Ca 1 *, and the probable electronic isola- 
tipn of this layer from the conducting CuO pyramidal planes, 
imply . that the formal charge formulation becomes 
Fb2Sr 2 YCu 1+ Cu! + Og in the non-superconducting compound. 
When Ca is substituted for Y, we propose that holes are 
accommodated only in the CuOj planes, and at the x= 0.5 
stoichiometry the formal charge formulation becomes 
. Pb^SrjYojCaojCu^Cuj^Oj , which is consistent with the cur- 



Fig 3 Resistivity in the a-b plane as a function of temperature 
for'a single crystal of Pb 2 Sr 2 (Dy,Ca)Cu 3 0 B+4 . Inset, typical tem- 
perature-dependent resistivity for a polycrystalHne sample or 
PbjSrjCY.CaJCujO,. 



rent assumption for previously known high-T c materials that 
holes are present in the CuO s pyramidal planes. 

For Pbj&iACujOg+a compounds with 6>0, excess oxygen 
must be accommodated near the Cu l+ planes, and a more 
complex hole-doping scheme may be operating. We expect thai 
in that case the compound does not respond in a simple fashion 
to the change in charge through doping of a rigid band; the 
oxygen inserted in the bonding neighbourhood of the reduced 
Cu and Pb ions may create the electronic states in which the 
charge is partly or fully accommodated. 

This new family of compounds has a unique crystal structure, 
yet it also reflects a concept common to all copper-oxide-based 
superconductors. By now it is well established that superconduc- 
tivity is associated with layers of Cu-0 octahedra, pyramids 
and squares. The remaining structural building blocks are seen 
as the electron acceptors which induce the holes necessary for 
superconductivity in the Cu-O layers. For YBa 1 Cuj0 6 +«, for 
example, we have shown in detail how the CuO« chains act as 
charge reservoirs, and how superconductivity depends on ch arge 
transfer between chains and planes'. 

To illustrate the concept of local charge distribution, one may 
rewrite the formulae of the high-T e copper-oxide superconduc- 
tors as follows: YBa^jOelCuO,]; SrjCaCujOsfBijO,]; 
BajCa^OjTljOj; Sr 2 (Y, CaJCu^PbjCuOw,]; where the 
structural components in square brackets act as reservoirs which 
control the charge on the superconducting Cu-0 planes. The 
PbO-CuOj-PbO reservoir layer is likely to be exceptionally 
flexible in accommodation of charge, and we therefore expect 
that a relationship between T e and oxygen stoichiometry as 
unusual as that for YBa 2 Cu J 0 4+a will eventually be observed. 
The wide ranges of metal-atom and oxygen-atom stoichiometrics 
in this new family of superconductors are of considerable inter- 
est, and warrant further study with the aim of understanding 
and optimizing the superconducting properties.. 
We thank D. W. Murphy and K. Rabe for helpful dfacussioo*. 



Received 11 October; accepted 28 Ottober IMS. 

1. Befrort, J.iG. & MvOer. K. A Z fro* BM.4S9-19J 11986). 
Z. Santera, 'A* Beech,?., Mmrcrio, M~& Csva,.R. J. tojstoa C On the press). 
$,8, f.d<(Sn«i.t«t 41, 7SO-7SJ (1988). . 



4. Via Dover, R. B, Cm, R. J, Batten, B. Si Maaun, E. A. Phyt IUa B35, 5337.SSM 

(1987). 

5. Cjvt, l J. «f at flr/rta C (in file pren). 



1 * 



BRIEF ATTACHMENT N 



IN THE UNITED STATES PATENT AND TRADEMARK OFFICE 



In re Patent Application of 
Applicants: Bednorz et al. 
Serial No.: 08/479,810 



Group Art Unit: 1751 
Examiner: M. Kopec 



Date: March 1, 2005 



Docket: YO987-074BZ 



Filed: June 7, 1995 



For: NEW SUPERCONDUCTIVE COMPOUNDS HAVING HIGH TRANSITION 
TEMPERATURE, METHODS FOR THEIR USE AND PREPARATION 



Commissioner for Patents 
P.O. Box 1450 
Alexandria, VA 22313-1450 



In response to the Office Action dated July 28, 2004, please consider the 
following: 



FIRST SUPPLEMENTAL AMENDMENT 



Sir: 



ATTACHMENT N 



Serial No.: 08/479,810 



Page 1 of 5 



Docket: YO987-074BZ 



LANDOLT-BORN STEIN 

Numerical Data and Funaional Relationships 
in Science and Technology 

New Series 

Editor in Chief: K.-H. Hellwege 

Group III : Crystal and Solid State Physics 

Volume 4 
Magnetic and Other Properties 
of Oxides and Related Compounds 

Part a 

J.B.Goodenough • W.Graper . F.Holtzberg • D.L.Huber 
R.A.Lefever • J.M.Longo • T.R. McGuire • S.Methfessel 

Editors: K.-H. Hellwege and A.M. Hellwege 



Springer-Verlag Berlin • Heidelberg • New York 1970 



N LANDOLT-BORNSTEIN 

is Zahlenwerte und Funktionen 

aus Naturwissenschaften und Technik 

Neue Serie 

Gesamtherausgabe: K.-H. Hellwege 



Gruppe III: Kristall-und Festkorperphysik 
Band 4 

Magnetische und andere Eigenschaften 
von Oxiden und verwandten Verbindungen 

Teil a 

J.B.Goodenough • W.Graper • F.Holtzberg • D.L.Huber 
R.A.Lefever • J.M.Longo • T.R. McGuire • S.Methfessel 

Herausgeber: K.-H. Hellwege und A.M. Hellwege 



1970 i Springer-Verlag Berlin • Heidelberg • New York 1970 



[Lit. S. 275 



3 Crystallographic and magnetic properties of perovskite and 
perovskite-related compounds*) 

3.0 Introduction — Einleitung 
3.0.1 General remarks - Allgemeines 



The perovskites form a family of compounds 
having a crystal structure similar to that of the 
mineral perovskite, CaTiOj. There are two classes 
of materials crystallizing with this general structure 
type: primarily ionic materials having the ideal 
chemical formula ABX„, (A = larger cation, B = 
smaller cation, X = anion), and alloys having the 
ideal formula M C XM|, (X = interstitial atom, M c 
and Mf are metal atoms). Of these two classes, the 
former is much larger and the more important. 

The stability of the ABX 3 perovskite structure 
is primarily derived from the electrostatic (Made- 
lung) energy achieved if cations occupy corner- 
shared octahedra. Thus the first prerequisite for a 
stable ABX 3 perovskite is the existence of stable, 
polar octahedral-site building blocks. This, in turn, 
requires that the B cation have a preference for 
octahedral coordination and that there be an effec- 
tive charge on the B cation. Since any A cation 
must occupy the relatively large anionic interstice 
created by corner-shared octahedra, a second pre- 
requisite is an appropriate size for the A cation. 
Where it is too large, the B-X bond length cannot 
be optimized, and hexagonal stacking with face- 
shared octahedra becomes competitive. Where the 
A cation is too small, A-X bonding stabilizes struc- 
tures having a smaller anionic coordination about 
the A cation. Thus ABX 3 perovskites are common- 
ly found in fluorides and oxides having B cations 
with a preference energy for octahedral coordina- 
tion. By contrast, the chlorides and sulfides, having 
larger anions, not only require the largest A cations, 
but also form layer structures, where the A cations 
are missing, because they have anionic d orbitals 
energetically available for orbital hybridization. 



There are many perovskite-related structures, 
and these have been included in these tables. For 
example, the structure can tolerate mixed systems 
such as A^jA^BXj and AB^B^Xj, A-cationic 
vacancies □ as in □ l _ I A I BX 3 , and cationic order- 
ing as in A 2 BB'X 6 . Although anion-deficient 
perovskites have been reported many times, the 
anion vacancies © are probably not distributed 
randomly. In compounds containing Fe s + ions, for 
example, they appear to condense in pairs at indi- 
vidual B-site octahedra to convert the local anion 
interstice from an octahedron to a tetrahedron. In 



Die Perowskite sind eine Gruppe von Verbin- 
dungen mit der gleichen Kristallstruktur wie das 
Mineral Perowskit, CaTiO s . Man unterscheidet zwei 
Klassen von Substanzen, die in diesem allgememen 
Strukturtyp kristallisieren: in erster Linie Ionen- 
verbindungen mit der idealen chemischen Formel 
ABX 3 (A = groBeres Kation, B = kleineres Kation, 
X = Anion) und Legierungen mit der idealen 
Formel M°XM f 3 (X = Zwischengitteratom. M« und 
M f = Metallatome). Von diesen beiden Klassen ist 
die erstere wesentlich umfangreicher und wichtiger. 

Die Stabilitat der ABX 3 -Perowskitstruktur be- 
ruht in erster Linie auf der elektrostatischen (Made- 
lung-) Energie, die dann zustande kommt, wenn 
Kationen Oktaeder mit gemeinsamen Ecken be- 
setzen. So ist die Existenz von stabilen, polaren 
Oktaeder-Bausteinen die erste Vorbedingung fur 
ein stabiles ABX 3 -Perowskit. Dies wiederum er- 
fordert, daB das B-Kation die Oktaeder-Koordina- 
tion bevorzugt und daB beim B-Kation eine effek- 
tive Ladung existiert. Da ein jedes A-Kation die 
relativ groBe Anionen-Lucke besetzen muB, die 
zwischen Oktaedern mit gemeinsamen Ecken ent- 
steht, ist die passende GroBe des A-Kations die 
zweite Vorbedingung. Wenn das A-Kation zu groB 
ist, laBt sich der optimale B-X-Bindungsabstand 
nicht erreichen, und eine hexagonale Packung von 
Oktaedern mit gemeinsamen Flachen kann ebenso 
auftreten. Wenn das A-Kation zu klein ist, ergibt 
die A-X-Bindung Strukturen mit einer kleineren 
Anionen-Koordination um das A-Kation. Daher 
sind ABXj-Perowskite gewohnlich unter den Fluo 
riden und Oxiden zu finden, in denen die B-Kati 
onen Oktaeder- Koordination energetisch bevor 
zugen. Dagegen erfordern Chloride und Sulfide, 
die groBere Anionen haben, nicht nur die groBten 
A-Kationen, sondern sie bilden, weil sie anionische 
i-Elektronenbahnen mit der richtigen Energie fiir 
eine Bahn-Hybridisierung haben, auch Schicht- 
strukturen, bei denen die A-Kationen ganz fehlen. 

Es gibt viele dem Perowskit verwandte Struk- 
turen, die in diese Tabellen aufgenommen wurden. 
Zum ' Beispiel konnen gemischte Systeme wit 
A^A^BXa und AB^B^X,, mit dieser Struktur 
auftreten, weiter A-Kationenlucken □ w ; - ; " 
□ 1 _ I A I BX 3 und geordnete Kationen wi_ 
AjBB'X,. t)ber Perowskite mit Anionenlucken 
ist schon haufig berichtet worden, vermutlich 
sind die Anionenleerstellen © nicht willkiirlich 
verteilt. In Verbindungen, die Fe 3 +-Ionen enthal- 
ten, scheinen sie z. B. paarweise im Oktaeder eines 
einzelnen B-Platzes zusammenzutreffen und die 



*) This work was sponsered by the U. S. Air Force. 



126 



Goodenough/Longo 



3.0 Introduction 



ipounds containing Ti 4+ ions, on the other hand, 
more probable that local rearrangements of the 
>ns form trigonal bipyramidal sites. Anion- 
deficient, ionic materials in which there are no A- 
cations, such as QWOj-,, have been shown to 
contain DBX 3 blocks connected by "shear" planes 
across which the occupied octahedra share common 
edges (Fig. 22). On the other hand, anion defi- 
ciencies may occur randomly in the M°X 1 _ I M5 
alloys. B-cation defects cannot occur, because the 
B-occupied octahedra form the basis of the ABX 3 - 
perovskite structure. Where there are apparent B- 
cation vacancies, as in A m B ro _ 1 X sm , there is either 
iterleaving of perovskite layers with A 2 X 2 layers 
(Fig. 23) or an interleaving of cubic (perovskite) 
stacking of AO s layers with regularly spaced hexago- 
nal stackings at which are located the B-ion vacan- 
(Fig. 24). Similarly, the series of compounds 
(AX) m (ABX 3 )„ crystallize with an interleaving of 
rocksalt layers (Fig. 25). Interleaving of cubic- 
stacked A0 3 layers and hexagonal-stacked layers 
also occurs in ABX 3 compounds having too large 
A cation to be accommodated by the perovskite 
structure (Fig. 3). Finally, there are a few alloys 
with interesting magnetic properties that can be 
classified as A 2 BB'X 6 compounds if the symbols B 
and B 1 are allowed to represent atomic clusters 
rather than single cations. These are illustrated, 
for example, by the alloy Al 2 (AlCo 12 )(Co 8 )B 6 (Fig. 
18). Sections 3.1 and 3.2 are devoted to descriptions 
of the perovskite and perovskite-related structures. 



The ABX S perovskites exhibit several interest- 
ing physical properties such as ferroelectricity (as in 
BaTi0 3 ), ferromagnetism (as in SrRuO,), weak 
ferromagnetism (as in LaFeO, or HoFe0 3 ), super- 
conductivity (as in SrTiOa-j;), a large thermal con- 
ductivity due to exciton transport (LaCoO,), insu- 
lator-to-metallic transitions of interest for thermis- 
tor applications (as in LaCoO s ), fluorescence com- 
patible with laser action (as in LaA10 3 :Nd), and 
transport properties of interest for high-tempera- 
ture thermoelectric power (as in La 2 Cu0 4 ). A few 
ABX 3 perovskites have been found that are si- 
multaneously antiferromagnetic and ferroelectric 
[5m 16, Mi7, Sm9]. The simultaneous occurrence of 
ferroelectricity and ferromagnetism has been report- 
ed for systems like Sr 0 ^La,, , 5 MnO,-ATi0 3 (A = 
Ba, Pb, Bi„.,K 0 . s ) [To3, fo6]. Many of the M c XMj 
perovskite alloys are ferromagnetic or ferrimagnetic, 
and a few exhibit first-order ferrimagnetic-to-ferro- 
magnetic transitions. Nevertheless, the significance 
of the entire perovskite family for the field of 
magnetism*) lies not yet in their technological 
applications, but in their provision of an isostruc- 
tural series of compounds having outer d electrons 
that are localized and spontaneously magnetic in 

*) The technologically important dielectric properties are 
outside the scope of this summary. See Vol. III/3 of the 
New Series of Landolt-Bornstein. 



dortige Anionenlucke von einem Oktaeder in einen 
Tetraeder umzuwandeln. Bei Verbindungen, die 
Ti 4 +-Ionen enthalten, ist es dagegen wahrschein- 
licher, daB die lokale Anordnung der Anionen tri- 
gonale Doppelpyramiden-Platze bildet. Fur Ionen- 
verbindungen mit Anionenlucken, die keine A- 
Kationen haben, wie QWO,.,, ist gezeigt worden, 
daB sie □BX 3 -B16cke enthalten, die durch „Gleit"- 
ebenen verbunden sind, in denen die besetzten 
Oktaeder gemeinsame Kanten innehaben (Fig. 22). 
In M C X 1 _ J M 3 -Legierungen konnen jedoch Anionen- 
lucken auch beliebig auftreten. B-Kationenliicken 
konnen nicht vorkommen, weil die von B besetzten 
Oktaeder die Basis der ABX 3 -Perowskitstruktur 
bilden. Wo scheinbare B-Kationenleerstellen auf- 
treten, wie in A ra B m _ 1 X sm , sind entweder A 2 X 2 - 
Schichten zwischen Perowskitschichten eingescho- 
ben (Fig. 23), Oder kubische (Perowskit-) Anord- 
nungen von AO s -Schichten wechseln mit regel- 
maBig verteilten hexagonalen Anordnungen, in 
denen die B-Ionenliicken auftreten, ab (Fig. 24). 
Ahnlich kristallisieren die Verbindungen der Reihe 
(AX) m (ABX 3 )„ mit einer Einschiebung von Stein- 
salzschichten (Fig. 25). Einschiebungen von ku- 
bisch gepackten A0 3 -Schichten und hexagonal ge- 
packten Schichten treten auch in solchen ABX 3 - 
Verbindungen auf, deren A- Ration fur die Perows- 
kit- Struktur zu groB ist (Fig. 3). SchlieBlich gibt 
es einige wenige Legierungen mit interessanten 
magnetischen Eigenschaften, die als A 2 BB'X 6 - 
Verbindungen eingeordnet werden konnen, wenn 
man unter den Symbolen B und B' Atomgruppen 
statt einzelner Kationen versteht, Dies gilt z. B. 
fur die Legierung Al 2 (AlCo 12 )(Co 8 )B s (Fig. 18). Die 
Abschnitte 3.1 und 3.2 sind der Beschreibung der 
Perowskit- und verwandter Strukturen gewidmet. 

Die ABX 3 -Perowskite weisen einige interessante 
physikalische Eigenschaften auf, wie Ferroelektrizi- 
tat (in BaTi0 3 ), Ferromagnetismus (in SrRu0 3 ), 
schwachen Ferromagnetismus (in LaFe0 3 Oder 
HoFe0 3 ), Supraleitfahigkeit (in SrTiO,-*), groBe 
Warmeleitfahigkeit durch Excitonentransport (i 
LaCoO,), fur Thermistoren interessante Obergange 
zwischen Nichtleiter und metallischem Leiter (in 
LaCoO s ), fur Laser- An wendungen geeignete Fluo- 
reszenz (in LaA10 s :Nd), und Transporteigenschaf- 
ten, die fur ThermospannungenbeihohenTempera- 
turen von Interesse sind (inLa 2 Cu0 4 ). Einige wenige 
ABX s -Perowskite wurden gefunden, die sowohl 
ferromagnetisch als auchferroelektrisch sind [Sm16, 
Mi7, Sm9]. Das gleichzeitige Auftreten von Ferro- 
elektrizitat und Ferromagnetismus wurde bei 
Systemen wie Sro^La^MnOj-ATiO, (A = 
Pb, Bi 0 . 5 K 0 . 6 ) [To3, fo6] beschrieben. VieleM c XMj- 
Perowskitlegierungen sind ferromagnetisch oderfer- 
rimagnetisch, und einige zeigen t)bergange erster 
Ordnung von Ferri- zu Ferromagnetismus. Trotz- 
dem liegt die Bedeutung der gesamten Perowskit- 
Familie fur den Magnetismus*) noch nicht in der 
technologischen Anwendung, sondern im Vorhan- 
densein einer isostrukturellen Reihe von Verbin- 

*) Die technologist wichtigen dielektrischen Eigenschaf- 
ten liegen nicht im Rahmen dieser Zusammenstellung. 
Siehe Band 1 1 1/3 der Neuen Seriedes Landolt-BornsU - 



Goodenoiigh/I.ongo 



127 



3.0 Einleitung 



[Lit. S. 275 



one member, collective and spontaneously magnetic 
in another, and collective and Pauli paramagnetic 
in yet another. This permits a systematic experi- 
mental investigation of the properties of the d elec- 
trons on passing through the transition from a 
localized character, where crystal-field plus super- 
exchange and /or double-exchange theories apply, 
to an uncorrected (except below a superconducting 
transition temperature) collective-electron charac- 
ter, where the conventional band theory applies. 
In addition, the simplicity of the perovskite ABX 3 
structure minimizes competitive magnetic inter- 
actions between neighboring magnetic cations. 
Therefore from a study of magnetic order, as re- 
vealed by neutron diffraction, together with de- 
tailed structural information, as revealed by x-ray 
diffraction, it has been possible to test the semi- 
empirical rules for 180° cation-anion-cation iso- 
tropic superexchange interactions between localized 
electrons, the double-exchange hypothesis, anti- 
symmetric exchange, and predictions of magnetic 
order and spontaneous atomic moments due to 
collective electrons. 



Section 3.3 presents the general phenomenologi- 
cal exchange Hamiltonian for localized electrons 
and summarizes the microscopic models for iso- 
tropic superexchange, double exchange, and anti- 
symmetric exchange. From these models, general 
rules for the interactions responsible for magnetic 
order are developed for comparison with the tabu- 
lated magnetic data. 



Section 3.4 presents the fundamental physical 
concepts needed to construct a qualitative phase 
diagram for the outer d electrons as a function of 
the number nj of electrons per relevant orbital, the 
magnitude of a nearest-neighbor transfer energy b, 
and the temperature T. It also summarizes the 
various characters of several physical properties 
imparted by outer electrons to show how they can 
be used to distinguish the electronic phases in differ- 
ent perovskites. Information from the tabulated 
data is used to show the influence of covalence and 
intra-atomic exchange, which help determine the 
parameter b, on the character of the electrons. 
Spontaneous collective-electron magnetism is seen 
to occur only in a narrow transitional interval of b 
between localized-electron magnetism and collec- 
tive-electron Pauli paramagnetism. 



Section 3.5 provides schematic energy diagrams 
for the alloys M C XM£. These are shown to be useful 
guides to predictions of the magnitudes of the 
atomic moments and the magnetic order. 



dungen mit auBeren d-Elektronen, die lokalisiert 
und spontan magnetisch in der einen Verbindung, 
kollektiv und spontan magnetisch in einer ande- 
ren, und kollektiv und Pauli-paramagnetisch in 
noch einer weiteren sind. Dies erlaubt systema- 
tische experimentelle Untersuchungen der Eigen- 
schaften der d-Elektronen, indem man von einem 
lokalisierten Zustand, in dem Kristallfeld plus 
Superaustausch- und/oder Doppelaustausch-Theo- 
riengelten, zu einem Zustand unkorrelierter Kollek- 
tivelektronen (auBer bei Temperaturen unterhalb 
des Obergangs zur Supraleitung) ubergeht, in dem 
die konventionelle Bandertheorie anzuwenden ist. 
Weiterhin fiihrt die Einfachheit der Perowskit- 
ABX 3 -Struktur zu minimalen konkurrierenden 
Wechselwirkungen zwischen benachbarten magne- 
tischen Kationen. Aufgrund der Untersuchung der 
magnetischen Ordnung, die man durch die Neutro- 
nenbeugung kennt, und einer genauen Kenntnis der 
Struktur, wie man sie durch Rontgenbeugung 
gewonnen hat, war es deshalb moglich, die halb- 
empirischen Gesetze tiber die isotrope 180°-Kation- 
Anion— Ration— Superaustausch— Wechselwirkung 
zwischen lokalisierten Elektronen, die Doppelaus- 
tausch-Hypothese, den antisymmetrischen Aus- 
tausch und Voraussagen fur magnetische Ord- 
nung und spontane Atom-Momente, die von Kollek- 
tivelektronen herriihren, zu priifen. 

' Der Abschnitt 3.3 enthalt den allgemeinen pha- 
nomenologischen Hamilton-Austausch-Operator 
fur lokalisierte Elektronen und faBt die mikroskopi- 
schen Modelle fur den isotropen Superaustausch, 
den Doppelaustausch und den antisymmetrischen 
Austausch zusammen. Aus diesen Modellen werden 
allgemeine Regeln fur die Wechselwirkungen, die 
fur die magnetische Ordnung verantwortlich sind, 
zum Vergleich mit den tabellierten Daten ent- 
wickelt. 

Der Abschnitt 3.4 enthalt die grundlegenden 
physikalischen Ideen, die fur die Herstellung eines 
qualitativen Phasendiagramms fur die auBeren d- 
Elektronen als Funktion der Elektronenzahl n t pro 
betreffenden Bahnzustand, der Grofle einer Uber- 
tragungsenergie b zwischen nachsten Nachbarn und 
der Temperatur T notwendig sind. AuBerdem wer- 
den hier verschiedene Charakteristika einiger durch 
die auBeren Elektronen gegebenen physikalischen 
Eigenschaften zusammengestellt, urn zu zeigen, wie 
man mit ihrer Hilfe die elektronischen Phasen ver- 
schiedener Perowskite unterscheiden kann. Auf 
Grund der tabellierten Werte wird der EinfluB 
Kovalenz und intra-atomarem Austausch, 
den Parameter b mitbestimmen, auf den Charakter 
der Elektronen gezeigt. Spontane Magnetisierung 
der Kollektivelektronen tritt, wie man sieht, ni 
einem schmalen Ubergangsintervall von b zwischen 
dem Magnetismus lokalisierter Elektronen und dem 
Pauli-Paramagnetismus der Kollektivelektronen 

Der Abschnitt 3.5 enthalt schematische Energie- 
diagramme f iir die Legierungen M C XM|. Es wird ge- 
zeigt, daB sie zu brauchbaren Voraussagen iiber die 
GroBe der Atom-Momcntc und die magnetische 
Ordnung fuhren konnen. 



Goodenough/Longo 



Ref. p. 275] 



3.0 Introduction 



In the introductions to the sections 3.2 — 3.5 
we have referenced the principle theoretical contri- 
bution discussed, but no attempt was made to do 
this systematically for the experimental contribu- 
tions, which are thoroughly referenced in the ta- 
bles. — In the crystallographic tables, the crystal 
parameters quoted either represent the most com- 
plete analysis, in our judgment, or belong to the 
most complete set of parameters for a series of 
similar compounds. They do not necessarily re- 
present the historical reference that established the 
unit-cell dimensions. 



Literature was considered up to 1969. 

Finally, we would like to thank David Maho- 
ney for his willing assistance, the library and publi- 
cations personnel of Lincoln Laboratory for their 
efficient support, and Mrs. G. E. Boyd for her help 
with all the foreign references. 



In den Einleitungen zu den Abschnitten 
3.2 —3.5 haben wir die grundlegenden theoretischen 
Beitrage, die diskutiert werden, mit Literaturhin- 
weisen versehen; fiir die experimentellen Beitrage 
haben wir dies nicht systematisch durchzufiihren 
versucht, da die entsprechenden Tabellen voll- 
standig mit Literaturhinweisen versehen sind. — 
In den kristallographischen Tabellen stellen die an- 
gefuhrten Kristallparameter entweder die nach 
unserer Beurteilung vollstandigste Analyse dar, 
oder sie gehoren zum vollstandigsten Satz von 
Parametern fiir eine Reihe ahnlicher Verbindungen. 
Sie geben nicht notwendigerweise den historischen 
Literaturhinweis, der die Dimensionen der Ein- 
heitszelle festlegte. 

Die Literatur wurde bis 1969 berucksichtigt. 

SchlieBlich mochten wir David Mahoney fur 
seine bereitwillige Hilfe, den Angestellten der Bi- 
bliothek und der Veroffentlichungsabteilung des 
Lincoln-Laboratoriums fiir ihre wirksame Unter- 
stiitzung und Mrs. G. E. Boyd fiir ihre Hilfe bei der 
auslandischen Literatur danken. 



a, b, c [A] 
». 9. V [deg] 

©trans, ©ord [°K] 

0 D [°K] 

r me it [°K] 

»-A,B,B' [A] 



©c [°K] 

0 N [°K] 

®p [°K] 
& [°K] 

C m [emu °K mole- 1 ] 
Xg [emu/g], [cm»/g] 
Xm [emu/mole] 
Pa. P A [Hb] 
Pn, P {tv) 
P* 

7Wk [°K] 



3.0.2 Symbols and units used in tables and figures 
Crystallographic structure 

symmetry classification for perovskite structures : C = cubic, H = hexagonal, 
R = rhombohedral, O = orthorhombic (a < c/YZ), O' = orthorhombic 
(c//2 < a), T = tetragonal, M = monoclinic, Tr = triclinic 

lattice parameters 

angle between crystallographic axes 

crystallographic transition and ordering temperatures 

Debye temperature 

melting temperature 

elastic constants 

crystalline strains 

radius of A, B, B' cation 

Magnetic properties (static measurements) 

see magnetic structure type from Fig. 26 

atomic moment and component of atomic moment parallel to net ferromagnetic 

moment in numbers of Bohr magnetons: f A = B A jjt B _ 
net magnetization per molecule in numbers of Bohr magneton: p m = n m y. B 
K eff = C m is the effective paramagnetic moment: pea = «eff V-b 
Curie temperature 

Neel temperature; extrapolated Neel temperature 
temperature for spin reorientation 

paramagnetic Curie temperature (0 P < 0 if antiferromagnetic coupling) 

temperature below which parasitic nf- deviates appreciably from 0.05 

molar Curie constant determined from Curie-Weiss law x m = C m l(T — 0 p ) 

specific paramagnetic susceptibility 

molar paramagnetic susceptibility 

atomic moment, atomic moment of element A 

molecular moment (of molecule xy) 

effective paramagnetic moment : p* = Yxm T 

isotropic exchange constant of Eq. (16) for near-neighbor interactions 
Ln-Fe interaction parameter defined by 

M (t) = a 0 (0) B (0 [1 + {d/t)l where / = T/0 C and B (<) is the Brillouin function 
domain wall energy density z 
net near-neighbor Weiss molecular field constant: = E { WyMf 



Goodenough/Longo 



129 



j [Gauss cn 
' \[emu/g] 
[emu/g] 

'sp 

H % [Oe] 
tfcrit [Oc] 



Cut 

T [ctb/r] 

H a 
Ht> 
H M 
H n 



r[Hz] 
Av [Hz] 
T, [sec] 
r, [sec] 
r te [sec] 



•Ea 

e [Ocm] 
S [|xV/°K] 
« [esu] 

c, «j, «± [cm- 3 ] 

ft [cm 2 /Vsec] 

r [sec] 

m* [g] 

D 0 [cm»/sec] 



T[°K] 



[Lit. S. 275 



magnetic moment per gram = specific magnetization 

specific parasitic (weak) magnetization as obtained from a = tr 0 + XgH& 

spontaneous specific magnetization 

externally applied field 

critical applied field for antiferromagnctic-ferromagnetic transition or for spin- 
flop transition 
cocrcivity 
cant angle 

magnetoelectric coefficients 

magnetostriction constant for [100] direction: A lo0 = — 46 1 /3(c 11 — c 12 ) 
components of the tensor describing the quadratic dependence of magnetization 

on applied field : Eq. (36) 
the Bohr magneton = 5585 cmu/g 
torque: T =oxH, 

Magnetic properties (resonance measurements) 

effective crystal line-anisotropy field 
exchange field 

spin-canting field (Dzialoshinskii field) 
internal magnetic field at the nucleus 
axial hyperfine field arising from nuclear polarization 

hyperfine field J- AS, where / = nuclear spin, S = net atomic spin, and the 
components of the interaction tensor are A 5 , A M , A,,, A„, A 2p . 

fraction of unpaired s, p„ or p n electron spins involved in covalent bonding : 

ft = 2 S Ag/Ana = i Njfc/* = 2SA a /A JP = i NJ& ft = 2SA n /A 2P = i N?£. 
See Eq. (4) for N e , N t , A,, X a , X„. 

nuclear quadrupole coupling constant and quadrupole splitting 

magnetoelastic coefficients : dgi = Z F xi f s and 



W a <5g • S + Sd- S 



dipolar and quadrupolai 

cli = ZGnej, where Jr^pin-iatUce = ^ B 

resonance frequency for NMR 
half-line width 

nuclear spin-lattice relaxation time 
nuclear spin-spin relaxation time 

nuclear spin-lattice relaxation time during a locking pulse 

Optical measurements 

index of refraction 
low-frequency dielectric constant 
Faraday rotation 

frequency of transverse and longitudinal optical modes 



Transport ti 

superconducting critical temperature 
Fermi energy 

activation energy for a small-polaron hop 

electrical resistivity 

Seebeck coefficient 

magnitude of the electronic charge 

charge-carrier density 

charge-carrier mobility 

charge-carrier collision time 

charge-carrier effective mass 

charge-carrier diffusion coefficient at £ a = 0 

density of unoccupied states: 2(2jiwJ k Tjh z Y n 

General properties 

temperature 
pressure 

specific heat at constant pressure 



130 



Goodenongh/Longo 



Ref. p. 275] 



3.1 ABX 3 perovskite structu! 



Abbreviations for text and indices 



AFMR 


antiferromagnetic resonance 


APR 


acoustic paramagnetic resonance 


BPW 


Bethe-Peierls-Weiss method 


C, cub 


cubic 


DS 


Danielson- Stevens method 


DTA 


differential thermal analysis 


ESR 


electron spin resonance = paramagnetic resonance 


i.e. 


face-centered permutation 


FMR 


ferromagnetic resonance 


F B 


ferromagnetic with reduced « A 


H, hex, hex (nL) 


hexagonal, hexagonal n-layer structure 


I.R. 


infrared 


Ln 


Lanthanon = any of the rare-earth elements 


MF 


molecular field approximation 


M, mon 


monoclinic 


NAR 


nuclear acoustic resonance 


NMR 


nuclear magnetic resonance 


ncub 


noncubic 


0, 0', orth 


orthorhombic (O: a < c/Yl; O' : cffl < a) 


P&S 


reference to preparation and structural information 


Prep. 


reference to material preparation 


Prop. 


reference to material properties 


pscub 


pseudocubic 


psmon 


pseudomonoclinic 


R, Th 


rhombohedral 


RW 


Rushbrooke-Wood method 


S. G. 


space group 


S.S. 


solid solution 


T, tetr 


tetragonal 


Tr, tr 


triclinic 



3.1 Descriptions of stoichiometric ABX 3 and M°XM| structures 

3.1.1 The ideal perovskite structure 

The ideal perovskite structure has the cubic unit cell of Fig. 1 with space group Pm3m. Fig. 1 (a) 
shows the corner-sharing octahedral units (BX, array in ABX, and XMj array in M C XM*), which form the 
stable skeleton of the structure. The A cation (or M c atom) occupies the body-center position. Fig. 1 (b) 
shows the unit cell with the A cation (or M° atom) at the origin, or corner position. This shows the face- 
centered-cubic character (with Cu s Au-type order) of the AX* or M C M| subarrays. Fig. 1 (c) shows the cubic 
perovskite on an hexagonal basis, with the c axis along the cubic [1 1 1] direction. The alternate AX, and B 
ionic layers each have cubic stacking. Also indicated is the ordering of B and B' layers in the ordered 
A(Bi /3 B l/ j)X 3 structures. 




a 1 c 

Fig. 1. ABX„ M°XMf. Ideal perovskite structure: a) B cation (or X atom) at origin, b) M« atom (or A cation) at origin, 
c) A cation at origin in hexagonal basis [Ga/tf]. 



Goodenough/Longo 



3.1 ABX 3 Perowskit-Struktur [Lit. S. 275 



The alloys M e XM, are stabilized by covalent M-X bonding and by metallic M-M bonding, so that they 
are generally cubic. Only in phases exhibiting complex magnetic order are there distortions to lower 
symmetry. On the other hand, the ABX 3 perovskites, which are primarily stabilized by the Madelung 
energy, are rarely cubic at normal temperatures. Madelung energy calculations are available [RolSa, 

^Altho'ugh cubic at high temperatures, most ABX S compounds exhibit distortions to lower symmetry 
below some temperature ©trens as a result of atomic displacements. Such displacive transitions can be 
described by a finite set of normal vibrational modes that become soft, their vibrational frequency in- 
creasing with T > ©trans- From Landau's theory of phase transitions, it may be argued [Hal, Co2] 
that at a second-order displacive transition, the frequency of one normal mode becomes zero lhus the 
occurrence of ferroelectricity in perovskite-type crystals such as BaTiO, has been correlated both theoreti- 
cally and experimentally [An2, Col, Ba17, Co28, Ne8, Sh26] with the existence of a transverse optic mode 
of lattice vibration having wave number ft « 0 and a temperature-dependent frequency w ~ { T - ©trans) • 

Similarly, in the case of LaAlO, softening of a single normal mode can produce the R3c-to-cubic 
transition, and this transition is probably second-order. Investigation [Hal] of the atomic displacements 
involved in other distortions from cubic symmetry, on the other hand, has shown that several normal 
modes' are involved, and these displacive transitions are first-order. 1<no ^ rr , „ • cl 

SrTiO s exhibits a tetragonal (DJ» with c/a = 1.00056) to cubic transition at ©trans = U0K [Ly2, Jtti] 
that appears to illustrate the softening of a triply degenerate phonon at the R point of the Bnlloum zone 
in the cubic phase. For T < ©trans, it splits into two zone-center phonons having a frequency depen- 
dence co ~ (©trans - T) 0 - 31 [F12]. In the presence of an external electric field £ a the symmetry is further 
reduced to C <v if £ a II c-axis, or C iT if £ a 1 c-axis, and the critical modes have the same symmetry as 
the ferroelectric TO modes. "Anticrossing" of the modes occurs for £ a = 1.5 kV/cm and 15 kV/cm [Ne7, 
Wo19]. Thus the observed [He5] maximum in the electric susceptibility of SrTxO, at very low tempera- 
tures does not appear to be associated with a ferroelectric transition. 

Theoretical interest in the analytic description of these phase transitions continues \_Go1a, Mu4a, 

Ta ihe physical origins of the various crystallographic distortions may be separated into three parts: 
relative ionic sizes, electron ordering among localized electrons, and electron ordering among collects 
electrons. 

3.1.2 The influence of relative ionic sizes 
3.1.2.1 Tolerance factor 

The first prerequisite for a stable perovskite structure is the existence of a stable BX 3 skeletal subarray. 
If the B-cation radius is r B < 0.51 A in oxides, for example, the B cation does not achieve its optimum 
B-0 separation in an octahedral site and therefore stabilizes a structure with a smaller anion coordination^ 
The AP+ ion is borderline, being stable in four, five or six coordination. However, Ga»+, Ge*+ and V + 
ions are definitely more stable in tetrahedral sites at ambient pressures. 

Given the BX. skeletal subarray, additional stabilization is achieved by accommodating a large A 
cation within this skeleton. Because there is an optimum A-X bond length, the presence of an A atom 
generally distorts the BX S array so as to optimize the A-X bonding. However, if th.s distortion is too large, 
then other space groups become competitive. Goldschmidt [Go2] defined the tolerable limits on the size 
of the A cation via a tolerance factor 

t = (r A + r x )0{r 3 +r x ) U) 
where r k r B r x are empirical radii of the respective ions. By geometry, the ideal cubic structure should 
have / = 1. The perovskite structure occurs only within the range 0.75 < t < 1.00 However, this is not 
a sufficient condition, since the A and B cations must, in themselves, be stable in twelvefold (12 or 8 + 4 or 
6+6) and sixfold coordinations. This sets lower bounds for the cationic radii. In oxides these bounds 
are r! > 0.90 A and r B > 0.51 A. In addition, Megaw [Me5] noted that, if 0.75 < / < 0.9, a cooperative 
buckling of the corner-shared octahedra to optimize the A-X bond lengths enlarges the unit cell ; on the 
other hand if 0.9 < t < 1, such buckling may not be found, although small distortions to rhombohedral 
symmetry occur. These structures are to be distinguished from perovskites that exhibit additional distor- 
tions as a result of electron ordering. The cubic phase is found at high temperatures or where the A-X 
bond is more ionic (especially if t « 1). 

Where the A cation is too small (r x < 0.9 A) to accommodate twelve nearest neighbors, a structure 
which the A and B cations are both six-coordinated becomes competitive. From the phase diagram of 
Fig. 2 for the oxides A»+B»+O s , which has been adapted from Schneider, Roth, and Waring [Sc/i], the 
initial competition is the C-M 2 O s structure, which contains two unusual types of corner-shared, six- 
coordinated sites. The C-M 2 0 3 structure consists of a face-centered-cubic array of cations with anions 
occupying * of the tetrahedral interstices in an ordered manner. Thus each cation has six out of eight 
near-neighbor anions at the corners of a circumscribing cube: i of the cations have two anions missing at 
the ends of a body diagonal and f of the cations have two anions missing at the end of a face diagonal oi 
the circumscribing cube. This arrangement minimizes the electrostatic repulsive forces between the cations. 



132 



Good enough/Longo 



Ref. p. 275] 



3.1 ABX 3 perovskite structure 




Fig. 2. General r A - r B phase diagram for A» + B ,+ 0, com- 
pounds based on ionic-size considerations. Exceptions may 
iir where considerations other than ionic radii r A ,f B 
ome important, as in the case A = Bi. A similar plot for 
B* + 0, perovskites is not useful because secondary con- 
siderations are amplified by ferroelectric distortions and the 
possibility of different layer sequences where larger A cations 
present. [Adapted from Sc13]. 



Given smaller A cations, however, electrostatic screening between face-shared octahedra can be 
achieved by displacements of the cations away from the shared face, and the structure competitive with 
perovskite is generally built from an hexagonal-close-packed anion array, which has octahedr^ holes 
sharing common faces along the c-axis. With one octahedral hole per amon and a cation/anion ratio 2/3 
the cations are ordered among theseholes so as to minimize the electrostatic energy I the A and B cations 
carry the same charge, as in A»+B*+O s , only pairs of cations share common octahedral-site faces and there 
is no ordering of A and B within the cationic array. This allows the electrostatic force between two cations 
sharing a common octahedral face to be reduced by displacements of the cations away from each other, 
thus distorting the octahedra. The result is the corundum structure of Al ? O a . If the cations A and B carry 
different charges as in A*+B<+O s , then the A and the B cations order into alternate puckered cationic 
(111) Planes of the rhombohedral corundum structure to form the ilmenite structure. However, where 
there Fs a large difference in the cationic charges, as in Li+Sb'+O, and Li+Nb-O s , two other ^ematives 
become competitive: (1) The A+ ions order in strings of face-shared octahedra so as to permit the 
B^-ion octahedra to share only edges with near-neighbor occupied octahedra. This ; structure , is illustra- 
ted by LiSbO, [Edl]. (2) After ordering B'+ and Li+ ions whithin each cationic (111) plane of the corun- 
dum structure in such a way that B>+ and Li+ ions share common octahedral-site faces^ each A+ cation 
then displaced into the far face of its octahedron, where it is equally spaced from B*+ cations above 
and below so long as the B*+ cations remain in the centers of their octahedra. Tins is the structure of 

^wSSthiAc^ 

stacking sequence from cubic to hexagonal. However, the change from the all-cubic stacking of the 
rhombohedral perovskite structure to the all-hexagonal stacking of the hexagonal (hex 2L) CsNiCl, 
sSture goes via the three intermediate steps shown in Fig. 3 [Lo1]. The first step is the ^agonal 
BaTiO, structure of Fig. 3 (c). It is a six-layer structure with stacking sequence a-b-c-a-c-b-a corresponding 
to one hexagonal stacking out of three. In this structure (hex. 6L), two-out-of-three B cations form pairs 
ing a Common octahedral-site face, and one-out-of-three B cation shares only common octahedral-site 
corners as'in the perovskite structure. Many ordered compounds A s B 8 B'0, are known to have this 
structure. kThe second step, illustrated by the hexagonal BaMnO, structure of Fig. 3(d) alternates hexa- 
gonal and cubic stackings with the sequence a-b-c-b-a. This four-layer structure (hex. 4 L) contains only 
B-cation pairs sharing common octahedral-site faces. The electrostatic forces between paired B-cations m 
Figs 3(c) (d) displace the paired cations from one another along the c axis, exactly as in the corundum 




Fig. 3. Stable structures intermediate to a) cubic perovskite and b) the two-layer hexagonal CsNiCl, structure, c) i sU-layer 
hexagon^ BaTiO, structure, d) four-layer hexagonal BaMnO, structure, e) nine-layer hexagonal BaRuO, structure. 
[Adapted from Ca2]. 



Goodenough/Longo 



3.1 ABX 3 Perowskit-Struktur [Lit. S. 275 



structure. The third step is the nine-layer (hex. 9L) structure of BaRuO,, which has two hexagonal 
stackings out of three in the sequence a-b-c-b-c-a-c-a-b-a. Here the B cations form strings of three sharing 
common octahedral-site faces along the c-axis. Electrostatic forces displace the two end-member B cations 
away from the center B cation of each string, as shown in Fig. 3(e). Because cubic stacking is stabilized 
by hydrostatic pressure, it is possible to convert under pressure and high temperature the hexagonal 
structures to the perovskite structure through the successive sequence of steps. This is well illustrated by 
the Ba^j-Stj-RuO, system as shown in Fig. 4(a). These particular intermediate structures appear to be 
stabilized by the cation displacements, but at the cost of alternating the stacking sequence. The (hex. 4L) 
structure, which has the maximum alternation of stacking, is not always found, and the intermediate 
structures tend to be stabilized by smaller B cations, as illustrated in Fig. 4(b). 




3.1.2.2 O-orthorhombic structure 

Cooperative buckling of corner-shared octahedra, although indexed on a monoclinic pseudocell in 
earlier work, may produce the orthorhombic primitive cell of Fig. 5 containing four formula units. It was^ 
first identified in single crystals of GdFeO, [Gel] and later confirmed [Co2/]. Powder photographs taken' 
with CrK a radiation could be indexed on the monoclinic pseudocell containing a single GdFeO s molecule, 
which is the origin of the earlier classification. The pseudocell dimensions of GdFeO a are a = c = 3.87 A, 
b = 3.83 A, /J = 92.8°, where 2& pMnd oeen = ctrae ceil- The true orthorhombic cell is referred to in the tables 
as O-orthorhombic and is distinguished from the O' -orthorhombic structure by a lattice-parameter ratio 




O x i #Xj @A «B 



134 



Goodenough/Longo 



Ref. p. 275] 



3.1 ABX 3 perovskite structi 



c/a > \f2, where a < b. The O'-orthorhombic structure, which has c/a < Y2, is the result of a super- 
posed J ahn-Teller (with or without spin-orbit coupling) distortion. It is also to be distinguished from ferro- 
electric 0 B -orthorhombic and OB-orthorhombic distortions in which each B cation is removed from the 
center of symmetry of its interstice. Other orthorhombic distortions have been reported for NdGaO, 
[Br26] and NaCoF, [OA5]. 

The O-orthorhombic unit cell has the probable space group Pbnm with A cations in positions 4 (c) : 
±(*. y,K\-*.\ + y. i)> the B cations in 4(b): (£. 0. 0; ± 0.J; 0, £, 0; 0, £, *), eight anions X„ in 
8 (d) : ±(x, y, z; £ — x, J + y, £ — z; x, y, \ + z; \ + x, J — y, z), and the remaining four anions X x in 
4 (c). Coordinates for the ions in GdFe0 3 are also given in Fig. 5. 

The buckling of the corner-shared octahedra decreases the cation-anion-cation angle <P from 180°. If 
the B cations and the anions are distinguished as B^J, 0, 0), B 2 (0, i, 0), B 3 (£, 0, £), X„ (J + x, £ — y, I), 
and X r (J - x, J + y, i). then the two representative angles are <P ab = - X n — B 2 ) and tf» c = 
(B 2 - Xi - Bj). Gilleo [Gi4] has estimated that in La(Co 0 2 Mn 0 8 )O a these angles are tf> ab = 150° ± 3° 
and 0 C = 177° ± 3° with Bj - 0„ = 1.95 A, B 2 - O rl = 2.10 A, B, — Oi = B 3 — Oi = 1.96 A. The 
angles in GdFeO a are similar. 

3.1.2.3 Rhombohedral sttuctures 

Where there is no buckling of the octahedra, the perovskites ABX, may have a small deformation 
from cubic to rhombohedral symmetry. Where this deformation does not enlarge the unit cell, it is 
possible to index it either on a unit cell containing two formula units, as shown in Fig. 6, or on a unit cell 
containing one formula unit. The corresponding rhombohedral angles are at 60 ° or a 90°. In the early 
literature, detailed anion positions were not known, and it was common to use the smaller cell with 
a » 90°. However, the anions are generally displaced so as to require the larger unit cell of Fig. 6, 
which has « « 60°. • 



B. 




Fig. 6. Rhombohedral ABXj structures: a) anion shifts for symmetry R3c; b) the simplest ionic displacements, corre- 
sponding to symmetry R3m for ordered A,BB'X, structures having r B ' > r B [RaJ]. 

Anion displacements from their ideal positions may be of three different types: (1) AX 3 (111) planes 
remain equidistant from neighboring B-cation (111) planes, leaving all the B-cations equivalent. Within 
these planes, three A— X distances are reduced and three are enlarged via cooperative rotations of the 
B-cation octahedra, as shown in Fig. 6(a). (2) The anions may move within pseudocubic {110} planes 
including the B-B axes so as to create two distinguishable B positions : B positions having a shorter B-X 
separation and B' positions having a larger B'-X separation. This gives the symmetry R3m, which allows 
the A cations to be displaced along the [111] axis so as to make thejeparations B-A ^ B'-A. (3) In the 
most general case, the anion displacements may be decomposed into R3c and R3m components. The result- 
ing symmetry R3 also gives distinguishable B and B' positions via its R3m component. 

Although the distinction between these possibilities has been determined in only a few cases, it appears 
that R3c can be anticipated unless there is a physical reason for creating two distinguishable positions B 
and B 1 . This conclusion is based on the fact that LaA10 3 has been shown to have the symmetry R3c by 
neutron diffraction, [Del 4} nuclear quadrupole resonance [MuS], electron-spin resonance, [Ki3] and x-ray 
techniques [Ge4b. De1T\. It is strongly supported by the observation [Ra3] that LaCoO s has the symmetry 
R3c at low temperatures, where all of the trivalent cobalt are in their low-spin 1 state, but has the symmetry 
R3 at higher temperatures where thermal activation creates a nearly equal population of high-spin and 
low-spin cobalt ions. These are crystallographically distinguishable, via different ionic radii, as B and B'. 



Goodenough/Longo 



135 



3.1 ABX S Perowskit-Struktur 



[Lit. S. 275 



3.1.3 The influence of localized-electron ordering 
3.1.3.1 Crystal-field theory 

Crystal-field theory rests on the assumption that the outer electrons to be described are localized at 
discrete atomic positions. This assumption is valid for outer / electrons; it is valid for d electrons in 
fluorides and in many oxides. Given this assumption, the Schroedinger equation 3? rp = E y> that describes 
the localized orbitals and their energies contains the Hamiltonian 

3#> = tf> 0 + V* + V mb + (V LS + V amh + V x + E V U ) (2) 

where JT 0 is the Hamiltonian for a hydrogen-like, spherical potential, V d is the atomic correction for 
spherical symmetry that enters if there is more than one outer d electron, and is the energy correc- 
tion due to the cubic component of the crystalline fields. For outer d electrons, V A and are generally 
rjI eV, and the ion is in a high-spin or a low-spin state depending upon the relative magnitudes of these 
two terms In the case of 3d electrons, the perturbations listed within the parentheses are all <0.1 eV, 
and they must be considered simultaneously. V LS = X L ■ S is the spin-orbit coupling energy, and covalent 
mixing reduces slightly the parameter A from its free-atom value. 7 ncu b is the noncubic component of the 
crystalline field, V x is the elastic coupling energy associated with cooperative local distortions, and Vn is 
the magnetic exchange energy coupling localized atomic moments on neighboring cations. 

Solution of the zero-order equation ^" 0 V= £ V & ves hydrogenic wave functions f Um = Ri{r) Yf{B, <f>). 
From the spherical harmonics Y?(8, <f>), the d electrons (/ = 2) have the following angular dependence 
and azimuthal-angular-momentum quantum number m derived from L z f = —ihdfldfi — mhf : 
A ~ (3** - r*)lr* = (3 cos'0 - 1) ; m = 0 

(/d ± »7e) ~ 2(« ± iyzW = sin 26 exp(±i<6) ; m = ±1 (3) 

(/b ± »/c) ~ (* 2 - y* ± i2*y)l r * = sin! 6 exp(±»2^); m = ±2 

where 6, $ are conventional spherical coordinates. The perturbation reflects the fact that outer 
electrons of parallel spin are excluded from one another and therefore screen each other less from the 
positive atomic nucleus than do those of antiparallel spin. This correction is responsible for Hund's 
highest-multiplicity rule for the free atoms. It influences the radial part of the wave function, and hence 
the relative energies of states of different spin, but not the angular part. 

Given the cartesian axes at a B cation formed by the principal axes of its octahedral interstice, the 
five d orbitals of Eq. (3) are separated into two symmetry groups; / A and/ B , which are directed along the 
cartesian axes toward near-neighbor anions, have E t symmetry and are referred to as e e orbitals ; / c , / D , 
and/ E , which are more stable because they are directed away from the near-neighbor anions, have r 2r 
symmetry and are referred to as t ig orbitals. The principal contribution to the cubic-field splitting 10 Dq 
of Tj- and E g energies is due to covalent mixing, not to electrostatic energies as calculated on a point- 
charge model. If covalent mixing with the near-neighbor anionic and A-cationic orbitals is introduced, 
then the crystalline localized orbitals of t 2t and e g symmetry become 

Vt = ^t(/t - Ktn + *a4>a) ( 4 > 
Ve = N e (f t -W.- KK) 
where /, and /, are linear combinations of the atomic f& / D , / E and / A , / B orbitals. The symmetrized 
anionic p sxndp orbitals are <f> t and ; the symmetrized A-catonic s, p orbitals are 4> k . The covalent- 
mixing parameters' \ a , X„, X A , A, are roughly proportional to the overlap integral for atomic orbitals on 
neighboring ions and inversely proportional to their energy separation. Initially, the energy separations of 
cationic d and ^ or <f>„ are given by E M - E lt the difference between the Madelung energy and ionization 
potentials for the "effective" ionic charges, so that by symmetry 

lODq = A M + (A| - (Ea - Ej), X„ < A„ (5) 
where A K is any electrostatic contribution to 10 Dq. The one-electron crystal-field splitting of the d-state 
manifold is shown in Fig. 7(a). The relationship X n < X a has been confirmed by nuclear magnetic 
resonance studies of KMnF„ KNiF, and KjNiCrF, \Sh30, Hu4]. In these experiments the fractional 
occupancies by unpaired spins of the 2s, ip a , and 2p„ orbitals are: 

fx, = 2SAJA 2t ~ NlXl, fx a = 2SAJA 2P ~ NlX\, fx n = 2SA„/A tv ~ N\X% 

where A, is the isotropic component and A a ,A n the anisotropic components of the hyperfine interaction 
tensor A lt entering the nuclear spin-electron spin coupling energy S s I t ■ A u • Sj. Interpretation of the 
phenomenological parameters X„, X a and 10 Dq has been discussed extensively [Hu4]. 

With more than one outer d electron or d hole, it is necessary to introduce V t \, which is responsible 
for Hund's highest multiplicity rule (highest net S and L) for the free atoms. For four outer electrons, 
the atomic ground term is therefore 5 D. In a crystal, this rule may break down as a result of the crystalline 

[36 Goodenough/Longo 



Ref. p. 275] 



3.1 ABX 3 perovskite structure 



fields. Schematically, the Hund splitting J e x for states of different spin and the one-electron splitting 10 Dq 
may be represented on the same energy diagram, as shown in Fig. 7 (b). It follows from this figure that 
with four to eight outer d electrons, the magnitude of the net ground-state spin depends upon whether 
(Jei - 10 Dq) is positive or negative. If A ex > 10 Dq, the ion is in a high-spin state; if A ex < 10 Dq 




Fig. 7. One-electron crystal-field splitting of the Estate manifold of a transition-metal B cation in a cubic perovskite: 
a) A tx = 0 and b) schematically for A ei jt 0, corresponding to more than one outer d electron. 

Hund's rule breaks down and the ion is in a low-spin state. Since decreases with larger radial exten- 
sion of the crystalline wave functions, it decreases with increasing covalent-mixing parameters X , X„. 
Simultaneously, from Eq. (5) it follows that 10 Dq increases with increasing covalency. Therefore there 
is a critical amount of covalent bonding beyond which Hund's rule breaks down. Covalency with a 
particular anionic sublattice increases with cationic charge and on going to the right through any long 
period of the periodic table. In oxides with the perovskite structure, only divalent and trivalent ions of 
the first long period are high-spin. Of these, trivalent nickel is low-spin and trivalent cobalt exhibits a 
variable high-spin to low-spin population as a function of temperature. 

In general, it is necessary to use a multi-electron notation for the outer d electrons. Whereas atomic D 
states are split by the crystalline fields as shown in Fig. 7, atomic F states are split as shown in Fig. 8. 



a 2 Electrons 
Fig. 8. Octahedral-site splitting of atomic F st 




T !g (e*t^cas t a + i^sinty 



i 2 Holts 

a) two-electron 'F states and b) two-hole 'F st 



Because the operator L s = —ihd/d<f> is imaginary, the crystal-field splitting of f B and / c quenches the 
orbital angular momentum associated with these orbitals, so that the e t orbitals have m = 0. 0 and the 
t 2e orbitals have m = 0, ± 1. An isomorphism between / c , / D , J E and atomic P orbitals simplifies calcula- 
tion of Vls. It is possible to treat the t is orbitals as atomic P orbitals if the sign of the spin-orbit-coupling 



Goodenough/Longo 



137 



3.1 ABX 3 Pcrowskit-StrukUir 



[Lit. S. 275 



parameter A is reversed [Gr9]. Therefore ground states having an orbital degeneracy and m # 0 are split 
by v ls into (2/ + 1) multiplet states corresponding to states of different J — L + S. However, the 
order of the levels is inverted (largest / lowest for less than five d electrons, smallest J lowest for more 
than five d electrons) because of the change in sign of A. According to the Lande interval rule, the separa- 
tion between states / and / + 1 is | A \ (J + 1). The first-order multiplet splittings, which, do not include 
mixing of higher states of similar symmetry, are shown in Fig. 9 for Fe*+ and Co 2+ ions. Note that the 
term is now identified by its symmetry character T ig or T lg rather than by its atomic orbital-momentum 
character D or F. Tab. 1 summarizes the various symmetry notations for different spin states. 




Fig. 9. Schematic spin-orbit plus trigonal-field, or tetragonal-field, splittings of cubic-field levels as u function of the 
ratio <5/( - A) for a) *T i% level of Fe»* and b) *T, t level of Co 2+ . 



Spin-orbit coupling introduces an axial symmetry to the charge distribution, where the spin (or 
atomic-moment) defines the axis. Therefore, if there is a noncubic component to the crystalline field 
(^ncub # 0), then there is a spin-lattice interaction via the orbital-lattice interaction that introduces a 
magnetic anisotropy. For localized electrons, this is a local, one-ion anisotropy. Conversely, if the spins 
are ordered below some transition temperature, then the local interstices have time to relax about the 
noncubic charge distribution, thereby distorting the octahedral site. Therefore there is an intimate 
connection between the noncubic symmetry and the magnitude of the multiplet splitting. The noncubic 
component is usually parametrized as 

Kncub =d(Ll- f), (6) 

and Fig. 9 includes the total perturbation V LS + V DCUb of the onc-elcctron and two-electron ground states. 

With one or two holes in a half-shell, the one-electron and two-electron energy diagrams are inverted. 
In these cases M L = 2\nn = 0,. so that V LS = 0, and there is no multiplet splitting. 

Tab. 1 also displays the general ground-state wave functions for a magnetically ordered phase having 
collinear spins. The coefficients a v a 2 , a s of the Kramers' doublets and b lt 6 2 of the singlets all depend 
upon the relative magnitudes of the five perturbation terms V LS + V ncub + V x + Jf z where sP z is 
the Zeeman energy due to the internal molecular field resulting from magnetic order. The molecular- 
field approximation is used for the first-order, isotropic magnetic-coupling energy ei , which is the 
dominant term in E [see discussion of Eq. (13)]. This gives 

tf-L «2/ p <S>S Z (7) 

where / p , the sum of all near-neighbor exchange parameters, can be determined from the temperature 
dependence of the magnetic susceptibility and z is along the axis of the average spin <S> on the neighboring 
cations. This term contributes to the spectroscopic-splitting factory, and hence to the net atomic moment, 
if v ls # °- In Tab. 1, the components of the wave functions are designated by the notation \M L , M s >, 
where M L , M s are the azimuthal quantum numbers for the net orbital and spin momenta. 



138 



Goodenough/Longo 



Ref. p. 275] 3.1 ABX 3 perovskitc structu! 



Tab. 1. Lowest terms and ground state wave function for octahedral-site cations having n localized outer d electrons 


+ 
o 

A 

J 

+ 


A A A A 

+ + + T 

1 1 1 i 

a? r+ a* : 

+ A A + A + 
A ~ ~ A ^ .*. 

r 1 1 r 1 + 

o+ + o+ 1 


+ 

o 
V 

| 

+ 


A 

A A -J» 
+ ° ~ 

7 + + 

-it 

AA r+ a a I: : 

A + A A 

. T+ T 

+ o_l I 




II II II II II II II II II II II II II 


1 




i? 


9%<?9 S? 9 * if 9 








in % * 

> o u S Pn U " 







Goodenough/Longo 139 



3.1 ABX 3 Perowskit-Struktur 



[Lit. S. 275 



3.1.3.2 Jahn-Teller distortions 

If the cubic-field ground state of the B cation is an orbitally two-fold-degenerate E g state, then the 
< 2e orbitals are either full or half -filled, so that M L = 0, and there is no spin-orbit coupling (V LS = 0). 
Jahn and Teller \Ja6] have shown that, if there is no perturbation available to remove a ground- 
state orbital degeneracy, then there will be a spontaneous distortion to lower local symmetry below some 
transition temperature ©trans < T meU , where T^t is the melting point. Since the energy gained by a local 
distortion is reduced by the work done against the elastic restoring forces of the crystal, transition tem- 
peratures ©tram are small for isolated ions. However, if all of the B cations are similar, then cooperative 
distortions are possible, and the net energy gained per ion is much greater because of the elastic-coupling 
energy V x of Eq. (2). Such a cooperative phenomenon is characterized by thermal hysteresis and a definite 
(usually first-order) transition temperature. Since they are due to electronic ordering, such transitions 
are martensitic. 

Van Vleck [Va15] pointed out that the normal vibrational modes that split an E t electronic state 
are themselves twofold-degenerate with symmetry E g . One mode gives the interstice a tetragonal distor- 
tion, the other an orthorhombic distortion. It follows that, from first-order theory, there is no static 
distortion of the interstice, only a dynamic coupling between the electronic charge density and the 
vibrational modes. Moreover, this dynamic coupling greatly enhances the two E t vibrational modes and 
gives a dynamic splitting of the electronic E t state. This mechanism has important consequences for the 
acoustic properties and, as discussed in 3.3, for the sign of the magnetic superexchange coupling. 

Inclusion in the theory of higher-order coupling terms and anharmonic elastic terms shows that a 
static, tetragonal (c/a > 1) distortion of the interstice is stable below some ©trans [KalO]. This sign for 
the static distortion was first established experimentally through the interpretation [Go 15] and further 
study of cooperative tetragonal-to-cubic transitions m spinel systems. However, application to the perov- 
skites requires a solution of the lowest-energy cooperative distortion via inclusion of the elastic-coupling 
energy V x . Goodenough [Go6] proposed that individual tetragonal (c/a > 1) octahedra order their long 
axes alternately along [100] and [010] axes of the pseudocubic cell. Kanamori [KalO] generalized this 
solution to include an orthorhombic component to the local-octahedron distortions. This gives B-B 
separations within (001) planes having a long (1) and a short (s) B-X separation and along the [001] axis 
two intermediate (m) B-X separations where s < m < (1 + s)/2. This prediction was later verified by 
Hepworth and Jack [He9] for □ MnF 3 and by Okazaki [OA/] for KCuF, (see Fig. 10). Superposition 
of this distortion on an O-orthorhombic cell stabilizes the unique axis along the orthorhombic c-axis, and 




140 



Goodenough/Longo 



Ref. p. 275] 



3.1 ABX 3 perovskite structure 



the axial ratios of the O-orthorhombic cell are transformed from a < c//2 to c/V2 < a. To signal the fact 
that a Jahn-Teller distortion (with or without spin-orbit coupling) has been superposed on a distortion 
due to relative ionic sizes, the notation O'-orthorhombic is used in Tab. 2 wherever c/V2 < a. 

The important B cations that exhibit dynamic and static Jahn-Teller stabilizations in the absence 
of spin-orbit coupling are :Cu 2 + 2 E g (t% g e g ), Cr 2 +andMn»+ 5 £ f (<*,«*), Ni m 2 £ e (*| r eJ), where Roman nui 
als are used for the valence state of a low-spin cation. Tab. 2 shows that O'-orthorhombic symmetry 
above a magnetic-ordering temperature is associated with these ions, provided the d electrons are localized, 
and only with these ions, with the exception of LaVO a and CeV0 3 , where sharply enhanced distortions 
appear abruptly below 0 N [Ro3; Go10]. The cubic 3 T Jg state of V s + is orbitally threefold-degenerate, so 
thatitmay_induce small distortions above 0 N , larger distortions below @ N (see discussion Go 14). LaNiO, 
remains R3c because the e g electrons are collective. In La2Lio.5Nio.5O4 crystals, on the other hand, the 
ordered Ni 111 ions have localized e g electrons, and there is a tetragonal (c/a > 1) distortion. The sign of 
this distortion is manifest by the large c/a ratio. Strictly speaking, this is not a Jahn-Teller distortion, since 
the K 2 NiF 4 structure is tetragonal, but ordering of the localized electron of unpaired spin in the tetragonal 
field distorts the Ni m octahedra to tetragonal symmetry with axes parallel to the unique axis. Pure 
Jahn-Teller distortions can be distinguished from distortions associated with spin-orbit coupling because 
they are independent of magnetic order and generally occur at a ©trans above the magnetic-ordering 
temperature. 

3.1.3.3 Spin-orbit coupling 

B cations having cubic-field ground-state terms T ig or T lg are orbitally threefold-degenerate with 
M L = 0, ±1. so that V LS ^ 0. The combined perturbations V LS + K ncnb separate into secular equations 
for different Mj, as shown in Fig. 9. With a single outer electron, the 2 T !g cubic-field term is split in two, 
the energies for different Mj shifting by 



£3/2 



where X > 0. In a 



= -i«5 + ii ± *{<5 S + X6 + ft *)«}«/« 



(8) 



E ah = = -\X. (9) 
and spin-orbit coupling leaves an orbitally twofold-degenerate ground state. Therefore it is necessary to 
consider an additional Jahn-Teller stabilization via V n cub + V x +Jfz- Goodenough \Go14] has 
shown that it is necessary to consider two temperature regions : T > 0 N and T < 0 N , where 0 N is the 
temperature below which the spins order collinearly. In the paramagnetic domain T > @ N , the molecular 
fields vanish (<S> =0) and, from Eq. (7), Jfz — 0. In this case, the ground-state energy varies as 
(<5 2 /A). Since the work done against elastic restoring forces is q 1 d 2 , there is a spontaneous Jahn-Teller 
distortion, corresponding to S > 0, at a ©trans > 0 N only if the product Xq t is relatively small. In the 
magnetically ordered state (T < ©*,), on the other hand, there is an internal molecular field Hua at each 
atom, which produces a Zeeman splitting of the orbitals of different spin. The magnitude of this splitting 
depends upon the spectroscopic splitting factor, which has the components 

So = 2 - 2 gl (6jX) and g ± = 2 + gl (5/X) (10) 
where gl > 0. Therefore the Zeeman splitting in the molecular fields is maximized by making <5 < 0 and 
having the spins parallel to the unique axis defined by 6. Further, this energy is linear in <5, so that a 
spontaneous distortion should occur at some ©trans < ©n. A similar argument holds for the orbitally 
twofold-degenerate / = 1 and / = i states of octahedral-site Fe 2 + s T le and Co 2 + *T lg . 

In summary, if multiplet splitting leaves a ground state with a twofold, accidental orbital degeneracy, 
then there is a spontaneous Jahn-Teller distortion at some ©trans that removes this degeneracy. If 
©trana > ©N. then <5 > 0. However, this alternative requires special crystallographic conditions that do 
not appear to be met in perovskites. On the other hand, a ©trans < ©n and <5 < 0 can be generally anti- 
cipated wherever the spins order collinearly and the d electrons are localized. Further, from Eqs. (3) and 
(6), it follows that T tt states (one outer t u electron) have 5 < 0 if the site symmetry is tetragonal (c/a > 1), 
whereas T u states (two outer t it electrons) have d < 0 if it is tetragonal (c/a < 1). Alternatively, distor- 
tions of the site symmetry may be to trigonal symmetry. A{<0 corresponds to a < 60° for T tt states, 
> 60° for T lg states. These relationships are also summarized in Tab. 1. Experimentally, Fe 2 + *T tg 
octahedra become trigonal (« < 60°) below © N , as exhibited by KFeF s , whereas Co'+ *T lg octahedra 
become tetragonal (c/a < 1) below ©u, as exhibited by KCoF„. Where ©trans = ©n. the magnetic- 
ordering temperature may be first-order. In addition, the spontaneous distortions introduce large magne- 
tostriction and magnetic anisotropy. 

The cubic-field ground state of V»+ *T lg is orbitally threefold-degenerate. As a result, any sponta- 
ous distortion must correspond to 6 < 0, i.e., tetragonal (c/a < 1) or trigonal (a > 60°). However, as 
the other cases: a ©trans < ©n is to be expected in the perovskite structure. The V 3 + ion generally 
curs in an O-orthorhombic perovskite, and superposition of a tegragonal (c/a < 1) distortion with 
coincident unique axes again results in O'-orthorhombic symmetry. The perovskite LaVO, exhibits an 
abrupt contraction of the c-axis on cooling through 0 N . 



Goodenough/Longo 



141 



3.1 ABX S Perowskit-Struktur 



3.1.4 The influence of collective-electron ordering 
3.1.4.1 Band theory 

Conventional band theory rests on three principal assumptions: (1) A description of the outer electrons 
may be built up from solutions of a single electron moving in a periodic potential. (2) Multiplet structure 
on individual atoms may be disregarded. (3) Electron-phonon interactions may be treated as a small 
perturbation. For an infinite crystal, the unperturbed solution of running waves in a periodic potential 
gives the Bloch functions and energies 

Vfcm = exp(tfc • r) u km (r); + Wftm* (11) 

where hk is the momentum of an electron of effective mass m* and Mfc(r) is a periodic function. In the 
tight-binding approximation appropriate for narrow bands, the Bloch functions arc 

Vk (r) = \lVW Texp (»& ■ K„) w(r - K„) 

where w(r — /t n ) is a localized wave function for the atom at K„ defined by 

w(r-lt B ) = l/ZATrexp [ik ■ (r - Jl„)]u*(r) 

and Wfc(r) is a localized crystalline orbital. At the Brilloin-zone boundries defined by 



2k- K + |K|* 



= 0, 



(12) 



where K is a reciprocal lattice vector, there are energy discontinuities in energy-momentum space. In 
polar insulators, this introduces an energy gap E g between occupied, primarily anionic states and empty, 
primarily cationic states. Cooperative displacements 8 of the cationic sublattice relative to the anionic 
sublattice may increase this gap, thereby stabilizing the total energy of the occupied states by e t 8 2 . Since 
the resulting elastic-strain energy is q 2 <5 2 , there can be a spontaneous displacement only for the exceptional 
case q 2 < e 2 and a ground state corresponding to a small distortion parameter <5. In this case vibrational 
entropy may stabilize the higher symmetry at the higher temperatures. This differs from the usual 
criterion for spontaneous distortions, where a term linear in d is identified. There appear to be two situa- 
tions occuring in perovskites where the requirement q 2 < is met: (1) Where B-cations have empty d 
orbitals, there is a critical range of covalent-mixing parameters through which the site preference changes 
from octahedral to tetrahedral. In this range q z is very small for B-cation displacements within an octa- 
hedron that reduce the coordination number from six towards four. The origin of the small q 2 is a balance 
of the electrostatic energy lost and covalent-bond energy gained on going to smaller anion coordination. 
(2) The high polarizability of the outer core electrons of Pb 2+ and Bi 3 + ions makes q„ relatively small, so 
that displacements that permit a relatively large e 2 can occur spontaneously. 

What distinguishes these spontaneous distortions from those due to an ordering of localized electrons 
is the displacement of the cations from the centers of symmetry of their interstices. (The Jahn-Teller 
distortions, with or without spin-orbit coupling, leave the cations in the centers of symmetry of their 
interstices.) Unlike the structures, such as corundum, where pairs of octahedra share a common face, 
these cationic displacements from the centers of symmetry of their interstices do not follow from point- 
charge electrostatic arguments. In polar insulators, these displacements lead to ferroelectricity or anti- 
ferroclectricity, and they often induce displacements of neighboring cations. Further, where the require- 
tq 2 f» e 2 occurs just above ©trans, there must be a strong interaction of the bonding (mostly anionic) 
electrons with those vibrational modes that anticipate the cooperative ionic displacements below ©trans- 
These "soft" vibrational modes impart several anomalous physical properties, including a high electric 
•cptibilil.y. 



3.1.4.2 Distortions due to B-X bonding 



Transition-metal cations having n 



niter d electrons have the following site prefer 
yst- Cr 6 '- Mn^ 

Nb 5 + Mo«+ Tc 7 + 



Taj 



where cations at the left of each row have definite octahedral-site (or larger anion coordination) preference 
and those to the right have definite tetrahedral-site preference. Those underlined by a solid line may be 
stabilized in the octahedral sites of a perovskite-type structure, but they tend to induce spontaneous 
ferroelectric or antiferroelectric distortions, the ions moving cooperatively out of the centers of symmetry 
of their interstices. The ions underlined by dashed lines only occur in ordered perovskites AjBB'O, and 
A 3 BBj0 9 . In general, they are found in tetrahedral sites or in strongly distorted octahedral sites. How- 
in the ordered perosvkites they are able to strongly polarize the anion near neighbors so as to stabilize 
the octahedral symmetry. 



142 



Ooodenough/r.ongo 



Ref. p. 275] 



3.1 ABX 3 perovskite structure 



It is significant that spontaneous" ferroelectric distortions are only induced by B cations if these are 
transition metal cations having empty d orbitals. It is also significant that the change from octahedral- 
site to tetrahedral-site preference is associated with a relative stabilization of the d orbitals (larger atomic 
number in any long period) as well as with a decrease in ionic size. (The ionic radii decrease in the order 
Y»+ Sc»+ Hf<+ z£+ Ta'+ Nb 5 + Ti«+ W«+, Mo«+, Re 7 + V»+. Tc'+. Cr*+, Mn'+). The greater the relative 
stability of the d orbitals, the larger are the parameters X a and ?. n of Eq. (4). and these are enhanced by 
any displacement that decreases a B-X separation. Such an enhancement stabilizes the occupied states 
at the expense of the d states, and a net stabilization can occur if the d states are empty Also the smaller 
the cationic size the smaller the elastic resistance to displacements within an octahedral interstice. (Phe- 
nomenological ionic models for the ferroelectric distortions have also been given [Me7 Ha33].) 

There are three B-cation displacements relative to their octahedral interstices that would simulta- 
neously stabilize the occupied anionic p n orbitals relative to the unoccupied < 2 orbitals: : (1) Tetragonal 
symmetry. Displacements along an [001] axis that create alternate long and short B-X distances along 
this axis would stabilize s, p a and the two p„ orbitals per anion on this axis and strongly polarize the 
charge density toward the short B-X separation. (2) Orthorhombic symmetry Displacement along a [110] 
axis that created two shortest and two longest B-X distances would stabilize the s, p r and the two p n 



l un two out of the three cartesian axes. (3) Rhombohedral symmetry. Displacement 
would stabilize the s, p a and the two p„ orbitals per anion on all the anions. These three 



orbitals per 
along a [111] 

^siA*^^^^^^^^ in the A-X separations, and the particular cooperative distortion 
that is stabilized depends upon the character of the A-X bonding. The covalency contnbution to the A-X 
bond increases with formal A cationic charge; for a fixed charge it decreases with increasing atomic 
number of the A cation down any column of the periodic table. If A-X covalent bonding is relatively 
strong and the perovskite is distorted to O-orthorhombic symmetry, all ferroelectric distortions may be 
quenched because the p n orbitals are stabilized by a-bonding with the A cations^ This appears to be 
illustrated by CaTiO s , and almost so by SrTiO s . On the other hand if the A atom is stabilized by a 
polarization of its outer core electrons (Pb»+ and Bi»+ as discussed in 3 1.4.3). then * tetragonal, ferro- 
electric distortion is stabilized so as to allow a cooperative displacement of the A and B ; cations the A 
cation moving along the [001] axis to stabilize two p n orbitals per anion not on [001] axes. This is illustrated 
by the PbTiO, structure of Fig. 12. If the covalency contnbution to the A-X bonding is relatively weak, 
then the B-X covalency contribution should dominate. For large A cations (/ > 0 V^^.**^ 
a ferroelectric, rhombohedral distortion at lowest temperatures as illustrated by BaTiO,. As the tempera- 
ture increases, successive distorted structures (Rg-Og Tj - C) uxboduce incremental ad ditions to 
the entropy. However, a small A cation and weak A-X covalency contnbution may lead to a ferroelectric 
Hirfn^ in™™^ on the O-orthorhombic structure to give the 0£-orthorhombic structure of CdTiO, 



rNaTaO, shown in Fig. 13. Even more c 



x distortions are found in NaNbOj [Vo6]. The i 



9 9 mo] 9 

A 1 1 

Cubic Mragonal 

Fig. 11. Possible B-cationic displacenie 
octahedra in ferroelectric or antifcrroolcctric dist 



0 0, 

1.78k 




Z38k 




Fig. 1 2. Tetragonal PbTiO, : a) environment of Ti 
and b) environment of l'b [SA2/]. 



Gooclenotigh/I.ongc 



3.1 ABX 8 Perowskit-Struktur 



[Lit. S. 275 



perature form has parallel pairs of (001) NbO s planes coupled antiparallel to give an antiferroelectric phase, 
as shown in Fig. 14. The Na atoms are also displaced antiparallel to one another. 

3.1.4.3 Distortions due to core polarization: Pb 2+ and Bi*+ 
Lead and bismuth are heavy ions, and the 6s orbitals are sufficiently more stable than the dp orbitals 
that Pb*+ and Bi'+ ions are commonly stable. However, the outer 6 s 2 core electrons have a relatively 
large radial extension, making the ionic radius large, and this reduces the overlap of the 6p orbitals with 
the orbitals on near-neighbor anions. This reduction in overlap reduces the strength of the A-X bond. 
However, hybridization of 6 s and dp orbitals, which costs the energy separation of 6 s and 6p orbitals, 
produces a polarization of the outer-core electrons, so that the effective ionic radius is much smaller on 
one side of the cation than on the other. This permits the formation of a much more stable bond on one 
side of the cation, and the energy gained in this bonding may be greater than the hybridization energy 
required to polarize the core. It is for this reason that Pb ,+ and Bi s+ ions are stabilized in many crystals 
with an asymmetric anion coordination. 

There are three possible displacements of the A cations that would stabilize the anion p„ orbitals 
(which ff-bond with the A cations) : (1) Tetragonal symmetry. Displacement of the A cations along [001] 
axes to stabilize the two p n orbitals per anion not on [001] axes, as found for PbTi0 3 (see Fig. 12). (2) Ortho- 
rhombic symmetry. Displacement of the A cations along [110] axes to stabilize strongly one p „ orbital per 
anion on [001] axes and less strongly one p„ orbital per anion not on [001] axes. The smallest induced 
distortion of the B-cation octahedra occurs for an antiferroelectric displacement of the type illustrated by 
PbZrO s , Fig. 15. (3) Rhombohedral symmetry. Displacement of the A cations along [111] axes to stabilize 
strongly one p„ orbital per anion. To be cooperative, such a distortion must be ferroelectric, as in BiFeO s , 
Fig. 16. Further, since the A cation is moved toward a B cation, there is an electrostatic repulsion between 
them that displaces the B cation from the center of symmetry of its interstice. 

Given spontaneous distortions due to A-cation displacements, there remains the possibility that elec- 
tron ordering among localized d electrons on B cations can superpose an additional distortion. "Whether 
this is the origin of the triclinic symmetry reported for ferromagnetic BiMnO s , where Mn 3 + is a Jahn- 
Teller ion, is not known. 




144 



Goodenough/Longo 



Ref. p. 275] 



3. 1 ABX 3 perovskite structun 



3.1.4.4 Competitive phases 

A few compounds have atomic radii compatible with the formation of a perovskite phase and yet 
are stabilized in other structures at ordinary temperature and pressure. Two important competitive 
structures of this type are represented by YAIO, and PbRuO,. Both of these compounds convert to 
the perovskite structure under hydrostatic pressure. 

The hexagonal YAK> 3 structure of Fig. 17(a) consists of close-packed layers having the sequence 
b-a-b'-a-b-c-b'-c-b, where b is an A-cation layer, b' is a B-X layer with anions stacked beneath A cations 
(6 stacking) and B cations in the trigonal bipyramids formed by face-shared tetrahedra in the hexagonal 
a-b-a or c-b-c anion-stacking sequence. The structure apparently forms because both the A cations and 
the B cations simultaneously approach the lower limit for cationic size: r B = 0.51 A, r k = 0.90 A. The 
small A1 J+ ion is relatively stable in the five-fold coordination of the trigonal-bipyramid sites, and the 
small Y 3 + ion is more stable in an eightfold (or 6 + 2) coordination instead of a twelvefold (or 9 + 3) 
coordination. These site preferences reflect an increased stabilization of the bonding, anionic orbitals as a 
result of closer cation-anion distances. 

The antiferromagnetic, ferroelectric compound YMnO, has a similar structure, but with an a-axis ]Pi 
larger than that of YA!O s to give six molecules per unit cell. The Mn 5+ ion can be stabilized in a trigonal- 
bipyramid site because it has four outer d electrons with configuration eje^aj, where the empty a t orbital 
is directed along the c-axis to bond covalently with the two collinear oxygen ions. The larger unit cell 
and the ferroelectricity are reflected in the complex magnetic order shown in Fig. 17(b). Below @ N , 
exchange striction favors antiferromagnetic Mn-O-O-Mn interactions. The ferroelectric transition that 
occurs above 600 °C is apparently due to the relatively large size of the Mn*+ ion, which creates a large 
enough interstice for the Y s+ ion that it is stabilized by a displacement from the center of symmetry of its 
interstice so as to lower its near-neighbor anion coordination from eight toward seven. 




Fig. 17. a) Comparison of the unit cells of YAIO, (solid lines) 
and YMnO, (dashed lines), b) Magnetic structure of YMnO, 
{Be36, Bc39\ 

a = 3.678 A, c = 10.52 A for YAIO,. 



Cubic PbRuOj gives an x-ray pattern of the pyrochlore structure, corresponding to chemical formula 
A^BjO,, and therefore may be written as PbjRiijO,©. This structure is competitive with the perovskite 
structure in several PbB 1+ O s compounds. It has been shown [Lo4] that the anion vacancies © are located 
at the centers of Pb 2+ -ion tetrahedra sharing common corners and that the electrostatic repulsion between 
the Pb ions may be counteracted by a transfer of the two outer-core electrons per Pb ion to the © sites, which 
act as traps for four electrons per vacancy. Thus the outer core electrons at the Pb 2+ ions induce a com- 
pletely new structure rather than a ferroelectric-type displacement of the A-cations within the perovskite 
structure. This new structure contains B cations in corner-shared octahedra, as in perovskite, but the 
B-X-B angle is reduced to about 135°. This structure is also stabilized in AgSbO, [Sc22] presumably 
because there is a small effective charge on the Ag+ ions. The pyrochlore A 2 B 2 0, structure itself is compet- 
itive if attempts are made to force a low valence state on one of the cations. 



fjndolt-Bfirnstcin. Ncuc Scrie TII/4.1 



Goodenough/Longo 



3.1 ABX 3 Perowskit-Struktur 



[Lit. S. 275 



3.1.5 Structures encountered with ordered B, B' cations 
3.1.5.1 Same B atom 

There are three ways of creating two different cations from the same atom : 

(1) Two A cations of different valence can create two different valence states of the same B atom, 
and these may order at lower temperature as a result of different cationic charge. The ordering temperature 
may be quite low, since only electron transfers are required for cationic ordering. This is illustrated by 
(Lao.jCao.s) (Mn^Mn^Oj, ^ch. has the Mn 3 +, Mn*+ ordering in a rocksalt-type array. Because 
Mn8+ ('|g e l) is a Jahn-Teller ion having localized outer d electrons, there is also a cooperative distortion 
to tetragonal (c/a > 1) symmetry of the Mn 3+ -occupied octahedra, and the ordering of these distortions 
gives a macroscopic distortion to tetragonal (c/a < 1) symmetry (see Fig. 26). 

(2) Where the energy difference between the high-spin and low-spin states of the B cation are nearly 
equal, the populations of the two energy states approach each other at higher temperatures. In LaCo0 3 , 
high-spin Co 3 + and low-spin Co 111 are separated by only E 3+ — £ nl 0.08 eV, and the populations of the 
two spin states are nearly equal at 400 "K. This temperature is sufficiently low that ordering ofjthe two 
different spin states occurs above this temperature, and the symmetry changes from R3c to R3 [Ra3]. 
In this case, it is the difference in ionic size and covalent bonding, which results in a difference in the 
effective ionic charge— not the formal ionic charge— that is the driving force for the ionic ordering. 

(3) Disproportionationof B m+ cations into B <m_1>+ and B (m+1)+ cations may create ions of different size 
and charge that become ordered. This is illustrated by DPdFj, which has been shown by magnetic 
susceptibility measurements to be Pd^Pd^F, [Ba19]. (The A cation is missing.) Such a disproportiona- 
tion permits the formation of (PdF,) 2- clusters in which the anionic orbitals are stabilized by strong 
covalent mixing with the u-bonding 4d orbitals of e t symmetry. This is accomplished by a shifting of the 
F~ ions toward the Pd 4 + ions and away from the Pd 2 + ions. Simultaneously, the anionic shift reduces 
covalent mixing in the occupied, antibonding 4d orbitals of e g symmetry at the Pd 2 + ions. These orbitals 
are therefore localized and further stabilized by intra-atomic exchange (Hund splitting), so that each Pd 2+ 
ion carries an atomic moment of 2|x B . Were there no disproportionation, the single electron per low-spin 
Pd m ion would occupy antibonding e e orbitals that were more unstable than the occupied, localized e e 
orbitals at the Pd 2 + ions. However, the transformation 2 Pd m Pd 2+ + Pd™ costs ionization energy, 
and this is usually too large (as in LaNiOj) for disproportionation to occur. 



3.1.5.2 Different B atoms 

There are many examples of ordered B, B' structures in compounds having different B atoms: 
Af B+B' 3 +F 6 ; A!+B 3 +B' 5 +0 6 , A|+B 2 +B'«+0„ Al+B+B^+O, ; A 3 +B 2 +B' 4 +0 6 , A|+B+B' 5 +0 6 , and A|+Bl+B' 8 +0 8 . 
Inthe A 2 BB'X B group, ordering is on alternate (111) planes of B cations, in the A 3 B 2 B'X, group the B' 
cations occupy every third B-cation (111) layer. Fig. 1 (c). The probability for an ordered arrangement 
of the B, B' cations is determined by the differences between their ionic charges and their ionic radii 
[Fe22, Fe23, Gal, GalO]. To first approximation, the order-disorder transition temperature induced 
by the charge difference Aq = (q' — q) at cations B' and B is 0^ ~ (A?) 2 . Thus superstructure has 
been observed in all the known compounds having (Aq) 2 = 36 and 16, whereas those having {Aq) 2 = 4 are 
disordered unless there is a relatively large difference in ionic sizes. The minimum difference 
in ionic size that results in ordered Af+B 3 +B' 5 +0 6 compounds is \r B — r B <\/r B « 0.09, and this has 
been achieved where B' = Nb or Ta, having empty d orbitals for the formation of stable (B'0 6 ) 7 - 
clusters, while the B cation has no relatively stable, empty i orbitals. 

Given the formation of (B'X 6 ) octahedra, a confusion arises as to where the structure corresponds to an 
ordered A 2 BB'O s perovskite built up of corner-shared octahedra plus A cations and where it corresponds 
to the isostructural (NH 4 ) 3 FeF s structure, which consists of discrete (B'Xj) octahedra separated by A and 
B cations. (The cubic KjNaAlF, structure with space group T&(Pa3) is similar to (NH 4 ) 3 FeF e , but has a 
lower symmetry because there are very small rotations of the (B'X 6 ) octahedra.) Some authors [Fe22] 
select as a criterion for the perovskite structure the cationic radius ratio r B /r A < 0.8 where r B > r B , . This 
decision is based on the observation that a plot of the cubic lattice parameter a 0 vs. B-cation radius r B is a 
straight line for r B /r A < 0.8, but bends over for r B jr k > 0.8. However, this probably reflects the ratio at 
which electrostatic forces inhibit (or reverse) any A-cation displacements rather than the ratio at which 
discrete (B'X,) octahedra are formed. For most physical properties this criterion is probably arbitrary. 

Without electron-ordering distortions superposed on the size effects, ordered' A 2 BB'X 6 perovskitescan 
be described by either the O-orthorhombic cell of Fig. 5 or by the rhombohedral R3 (or R3m) cell of Fig. 6. 
Where a =60°, a tetramolecular cubic cell may be chosen provided the A cations are not displaced from 
their ideal positions. Like cubic (NH 4 ) 3 FeF„, the cubic cell has the space group 0£ (Fm3m) withB cations 
in 4(b) (iii); f.c, A cations in 8(c) ± (J, \, £); fx., B' cations in 4(a) (0, 0, 0); f. c, and X-anions in 
24(e) ± (u, 0, 0; 0, u, 0; 0, 0, u); f.c. with 0.2 < u < 0.25. However, even where a = 60°, motions of the 
A cations along the [111] axes may occur, thereby destroying the cubic symmetry. 



146 



Goodenough/Longo 



Ref. p. 275] 



3.1 ABX 3 perovskite structure 



If an electron-ordering transition superposes a distortion at every other octahedron of Fig. 5, either the 
B or the B' octahedra remaining cubic, cooperative elastic interactions between the distorted' octahedra 
give a further reduction in symmetry. The resulting monoclinic cell [Fi9, BIS], which is pseudotriclinic, is 
not to be confused with the pseudomonoclinic symmetry reported in early work for the O-orthorhombic 
structures. The origin of the superposed electron-ordering transition could be either a Jahn-Teller ordering 
of localized electrons or a ferroelectric-type displacement of the anions about a (B'X,.) octahedron. 

Several Ca 2 B'+Ta 5 +0, and SrjB'+Nt^+Oj perovskites having B = rare-earth atom exhibit the mono- 
clinic symmetry of a distorted O-orthorhombic cell [Fi8]. Since the 4/ electrons at the rare-earth ions are 
localized, it is tempting to attribute this to a Jahn-Teller distortion with spin-orbit coupling. Although 
Fig. 9 shows that the octahedral site splitting of one-electron 4/ orbitals gives orbitally threefold-degene- 
rate levels having an accidental degeneracy that is not removed by spin-orbit coupling, nevertheless there 
are two reasons why this explanation cannot be correct: (1) There is no magnetic ordering of the 4/ elec- 
trons at room temperature and (2) Sr 2 GdNbO s shows the distortion even though Gd 3 + has a half-filled 4/ 7 
shell, which has no orbital degeneracy associated with the ground state. It is therefore concluded that the 
additional distortions are due to the potentially ferroelectric cations Nb 5+ and Ta 5 +. 

3.1.5.3 Complex alloys A^BB'Xg, where B = M 13 , B' = M 8 

Several complex interstitial alloys have a formal structural relationship to the ordered perovskite 
A 2 BB'X 6 as well as interesting magnetic properties. In this group, having space group Fm3m, the B posi- 
tion is occupied by a thirteen-atom cluster consisting of a metal atom at position 4 (a) at the center of a 
cubo-octahedral, twelve-atom cluster of M atoms at positions 48 (h) ; the B' position is occupied by a simple 
cube of eight M' atoms at 32(f). The three principal axes of each cluster are along the cubic axes of the 
perovskite cell, as shown schematically in Fig. 18, so that each X atom at positions 24(e) has eight near 
neighbors. The eight A atoms of the tetra-molecular cell are at the 8 (c) positions. The 4(b) position at 
the center of the M£ clusters is empty. Alloys with this structure include the ferromagnetic borides 
AljHAlMuHMJHB,, where M = Fe, Co, Ni, as well as Cr^C,. 




Fig. 18. One quadrant of the A,BB'X, structure showing 
the atomic positions of the B = M„ and B' = 111', clusters 
[Wei 9], 



3.1.6 First-order magnetic transition in M C XM£ perovskites 

Many perovskites M c XMj exhibit first-order phase changes at magnetic-ordering transitions. Most of 
these are reported to be cubic-to-cubic transitions, but in ZnCMn, it is a tetragonal (ferrimagnetic) -to- 
cubic (ferromagnetic) transition. These crystallographic changes are induced by a complex interplay of 
collective electrons in overlapping bands. Because of the intimate connection with the magnetic proper- 
ties and because of the necessarily speculative character of any model at this time, discussion of these 
compounds is deferred to 3.5. 




3.1 ABX 3 Perowskit-Struktur 



[Lit. S. 275 



3.1.7 Data: Crystallographic properties of ABX 3 , A 2 BBX 8 , A 3 B^X 9 and A(BsBX)X 3 
compounds with perovskite or perovskite-related structure (Tab. 2) 



Tab. 2. 

Within any section, the compounds are in general first ordered according to the atomic number of the 
B cation and then by the basicity of the A cation. For the ordered perovskites of Tab. 2 b, c, d, the com- 
pounds are further ordered by the atomic number of the other B cation. The order of the sections is as 
follows : 

Tab. 2a - ABX 3 
A 2 +LiH 3 

A(H 2 0) (Li j/3 ) 3 ; A = I-\ Br" 1 
A+B 2 +X 3 ; X = F -1 , CI- 1 , Br- 1 
A+B 6 +0 3 ; B = V, Nb, Sb, Ta, I, Pa, U 

A 2 +B 4 +0 3 ; B = Ti, V, Cr, Mn, Fe, Co, Ni, Ge, Zr, Mo, Tc, Ru, Sn, Ce, Pr, Hf, Re, Ir, Pb, Th. U, 
Np, Pu 

A*+B«+X 3 or A s +B 3 +X 3 ; X = S or Se, B = Ti, Zr, Ta, In, Ga 

A 3 +B 3 +0 3 ; B = Al, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Ga, Y, Nb, Rh, In, Ho, Er, Tm, Yb, Lu 
Tab. 2b - AjBB'X, 

A 2 BB 3 +Xj; X = F _1 , CI -1 , B 3 + = Al, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Ga, Ag, In, Ce, Ft, Au, TI 
A 2 +A 3 +B 3 +B<+0 6 ; B 4 + = Ti, Ir 
Aj,BB n +0 6 ; B 4+ = Ti, Mn, Ge, Zr, Ru, Ir 

B 5 + = V, Nb, Sb, Ta, Bi, Pa, Pu 

B«+ = Mo, Te, W, Re s +. 5 +, Os 6 +. 5 +, U«+. 5 +, Np 6 +, Pu«+ 
B'+ = Tc, Re, Os, I 



Tab. 2c - AjBBjOj 

A 3 BB| + 0 9 ; B 5 + = Nb, Ru, Sb, Ta 

La 3 Co 2 B 5 +0 9 ; B 5 + = Nb, Sb 

A 3 B 2 B 6 +0 9 ; B 6 + = Mo, W, Re, U 

Tab. 2d - A 2 +(B i b;b; , )O s 



Goodenough/Longo 



Abbreviations in Tab. 2: 

Symmetry: C = cubic, H = hexagonal, M = monoclinic, 0 = orthorhombic (a < 0' = orthorhombic (c\fl < a), R = rhombohedral, T = tetragonal, Tr = triclinic. 

Remarks: for abbreviations, see p. 131. 
Tab. 2a. ABX 3 compounds 


ll 


H 

.a 


1 


1 1 ia \ 

i i H I If i 

u i ii as • 


! 

s 

■ I i 

£ 1 


1 


% fih ll 1323 1 Sdslsl 3312 s 


f 


s 




1 

14.45 
22.13 

8.72 

8.19 

7.676 
3.933 

6.19 
9.922 

6.048 




III 


« ■< 


imM^imimm mi 


o oooo « oo C KWhS o ohooWo oooo W 


I 


J i 

1 1 aSIf i 11 1 f iff Si sill" 1 



Goodenough/Longo 



3.1 ABX 3 Perowskit-Struktur [Lit. S. 275 



J? 


in 3.3.4, 
Tab. 

1 










3 


i: 

r 
ii 


i 

5 3' 
I I 

ilV 

1 z 11 


a and b axis said to double 
Hex (2L), P&S [Se2] 


Hex (6L), <9 N = 54 °K, P&S [SH4, Be19], neu- 
| tron diffraction [Pt7], optical properties [S/.2#, 
St30], NMR [Aft4, We//], AFMR [WH4], mag- 
netic properties [Lei, Le4, Set], S.S. with K and 
Na [Be 19a] 

High pressure phase, P&S [Sy1] 

P&S [Si/4, Be19, Co25, Hoi 7], cubic to T = 20 °K 
[Te4], dielectric properties [Igf, Ch4a], com- 
pressibility [St29], I.R. spectra [Ax2, PeS], 
bibliography [FrIOa] 

P&S [Be14, SH4, Cr4, Be2, Be4, Kn3, Ok2, Ok3, 
Ok4, Be53, Ok6, Ho17, Gula], S.S. with Co + Ni 
[Ha2S], I.R. spectra [Ax2, Pe5. Yo2], bibliog- 
raphy [FrIOa] 

T = 95 "K, (c/a > V~2) 1 84 > T > 84 °K [Be3, De3, Ok6] 

T = 65°K, (c/a < Yl) T < 84°K [Be3, De3, 0k6] 

Prep. [Ho17, Be19b], a and b axis doubled [S»7 4], 
P&S [MaP] 

P&S [£>4, Ho17, Co2S], neutron diffraction [Pi/] 

Hex (6L), 0 N = 86 °K, AFMR & ESR [ife/, Sh3, 
ShS] 

Cubic T > 458 °C, AFMR & ESR [Ke1, ShS] 


i 


111 SS§5£S£23 


i 




f 


s? 
s 

II 




§35 ii mm- 1 


III il 


-o -< 






3 




m 






4.328 
4.2396 

4.186 

5.885 
5.900 
5.568 

4.238 
4.250 
7.288 
7.164 

10.024 


I 


T* 


X t-'tr'Oh* 




X 


OO O OOOooWWH 


I 
a 

3 


lift fr if! I 


i i IMi 



Goodenough/Longo 



i 1 


¥ ■ - - 


! 


mi an 

111.1 j 11 La Slili 
mm wmm s fnsass 


i 


III 1 gSlSSlSlls sills 5 S3S3 11 1 


f 


h 

8 




14.855 

7.890 

6.045 
6.020 
22.61 
14.67 

4.049 
7.792 

6.032 

5.996 

5.225 
22.32 
14.54 
14.31 




1 § 




}m S IssSSIsslI 1 93SS ii ! 


I 


Gffioo o fiOooKWKWoo HOouS K WKKW oo o 


* 

i 


£ : 

ii 

\i i i Ml ii ii 5 ! f f 



Goodenough/Longo 



3.1 ABX S Perowskit-Struktur [Lit. S. 275 



I s 


cort^^o vovo NO 


J 


: I" Hi 

"I |: 

ill ill It: 


I ; 
Hi 


Hex (6L), high pressure phase 
P&S [Cr4, Lul] 

Hex (6L) high temperature form 

P&S [Lul, Ma29], thermal conductivity [Sug], 

optical properties: Ni, Mn [Fell, Fe15], I.R. 

spectra [Yo2, Pe2a] 
P&S [Lu1, Ru8, Ba1, Ma9, MalO, SctO] 

Hex (6L) 

Nuclear quadrupole resonance [VoO] 

Cubic T > 155 °C, ferroelectric transition at 155°C 


3333a 15 §11 I3S3S 1 11 3S333 SSSS 11 


f 


II II II II II 




§ § 1 lim Bm S is ss 3 M 




ed) 

5.524 

11.37 

13.785 

14.189 
14.43 

5.569 


J 

1 

d 

- 

152 


i$m is m §isis i !? ssiii m n 


£ : 


II 

ft ilia ii ill 1 1 in 



Goodenough/Longo 



Ref. p. 275] 



3.1 ABX 3 perovskite structuS 



H% v CO 

h to X (U 



5? 2£ 



3 if i-asi 

3 -g 2 «o m 11 to » II g 



Goodenough/Longo 



153 



3.1 ABX S Perowskit-Struktur 



[Lit. S. 275 



ill 

ii II 

lliii 




2 1 liSSl li 



s hhhh 



1 E 93 5 



1 I 5 



& si 



i m mum 



O OK^UO HO 



Goodenough/Longo 



3.1 ABX 3 Perowskit-Struktui 



[Lit. S. 275 



is 

1_ 




- . 

HR|flil$1ii<tf$ll«Mlif 

a * £ •§ £ §*& 8. g $ -s/3 £&: au £ .g u ii * ™ -g ■§ ^ 



&S.S 



1 v 5" c 



£ £ i 1 1 1 



0 - H H »p HHP H » „ 

5 SjJ^rfjSS 



Goodenough/Longo 



f.p. 275] 



3.1 ABX 3 perovskite structure 



ill I Ml 

H4 if 1 W! i 

14111 si J II illfJ 



!!!!! sli 



ai in hi 

i an an! m 



Mmim Ssstfi^ B<aftS ^ 
rrini Umm* m&ki* 




Ills I isiisili^^i iliiiili ii i is 



Nllllfspiipi ip n 



I 



1! I sis 



_oOoK X XXXXoOoXXXXXXO 0«OH«Ooo HO O OH 

Iff! ■ m III iiii'l 



Goodenough /Longo 



3.1 ABX S Perowskit-Struktur [Lit. S. 275 






„KoKooo UO uouo oo oo oKooOuS W 















•a 


(cor 










Compo 


0 2 ? 5 „ » „ 

1 oo'oooo 

p <s 3 1 <s <s 3 

< mwfflooffl 


SrZrO, 


o" o 

N N 

O (U 




99 o o o o 

oW wogpq 



158 Goodenough/Longo 



Ref. p. 275] 



3.1 ABX 3 perovskite structifl 



I 



is 
I 



5*1 3 1 

mi u 

ms 1 



1. l ill: 

m 

i mm$Mmmm mMt 

3313311 n mi i mnmihi 



mi s HI i 



III 5 35 5 2 



5ss 5 is! ! 



^Koooooo 00 o§uo o uoooouoShuoK^ouooo 




Goodenough/Longo 



3.1 ABX S Perowskit-Struktur [Lit. S. 275 



Magnetic 
Data 


in 3.3.4. 
Tab. 








Remarks 


P&S [Ho2, NalS. Me4, Be24] 

Pseudocubic, S.S. with Ba [Be24] 

Pseudooubic 

Pseudocubic 

Pseudocubic 

P&S [Sc16, Ru4, Tr9], S.S. with BaTiO, [Va9] 

Pseudocubic 
Pseudocubic 


Hex(2L), P&S [No9, As 3b], orthorhombic and 

tetragonal modifications [Ha6] 
Hex (2L), P&S [No 9] 

Hex(2L), P&S [No9], orthorhombic and tetra- 
gonal modifications [Ha6~] 
"Layer structure" P&S [No9] 
Distorted perovskite, P&S [Ha6, No9, As 3b] 
Hex (2L), P&S [No9] 
Distorted perovskite, P&S [No9] 
Distorted perovskite 
Hex (2L) P&S [No9] 
Hex (2L) P&S [No 9] 
A = Sr and Pb— not perovskite 
Ln = La, Ce, Pr, Nd and Sm; 


J 

S 

IS 

1-1 


3 a 

* §2£ 

J Q w « >" V 

% s> ^Ll 9, & ii % % 

P4 h PM PM 


Ref. 


1 1 1 1 1 .3 s s $ 


S; "Be <N *\ *B *~ "5 o ^ 

o ^ til ^u^uo^-^fe;^ 




















5.74 

6.033 
5.829 

11.752 
7.050 
6.025 
14.23 
14.05 
5.742 
5.987 
11.9 
20.98 








9.983 

9.79 
9.58 

6.8 
« 11.78 




8.985 
8.84 
8.74 

8.960 
4.387 
4.384 
4.357 
4.28 

= S, Se 


6.77 

7.054 
6.730 

7*!o37 
7.188 
13.49 
13.07 
6.847 
7.134 
11.0 
« 3.95 


2 


5.357 

3.818 

5.327 
5.307 




X 

^OOOOOOOOO ^ 


X X X HOBOOWSOO 


X 




Compound 


I f 
o „ „ „ „ » . X 


pq cqw Ph PQ pq w O pq pq <! ,3 


1 1 i H 



1 60 Goodenough/Longo 



3. 1 ABX 3 perovskite structure 



1 



li- 



lt \ MSP 



Hi Pi M ?H * T 

tliffinll,, 



Ifiaifll^piKiiifiil llfl III 



as 

Is 



s !|! si p ppfss s p 1 lis 



92 I a IS 2 S si ! g 55S 



H.rt OO tiOWO WO WO WOWOWOO OiWf-tftfOOOOO 



r 

iii! ii n !!»' 



Landolt-Borostein, Nciic Serie IIl/4a 



Goodenough/Longo 



3.1 ABX S Perowskit-Struktur [Lit. S. 275 



'■0 m 


" " — * - — .... - 


H 

I 


I 1 

I ■ 1 Jl 
I L ISlIIil 


% 

Bmn i 

0MMM 




Isslsl 11 !!!!!! Illllllll Ilililllis 




s 

Is 

is 

II 11 








5.76 
5.756 
5.71 
5.71 
5.712 
4.127 

5.521 
5.568 
5.655 

5.648 
5.659 
5.665 
5.657 
5.647 
5.633 
5.633 
5.665 
5.540 

5.486 
5.562 
5.579 
5.588 
5.614 
5.602 
5.604 
5.605 
5.58 
5.61 




mm b mm mmm mmm-? 




^OOOOOH OO HHOOOU OOOOOOOOO OOOOOOOOOO 


! 


fins if Hi! mm mm 



Goodenough/Longo 




% _o KoOoOOOOOOOO o ooo ooo 
I 

i I ii 

j |g Mg$ f t at i t 1 f f g f <? s" 



Goodenough/Longo 



3.1 ABX 3 Perowskit-Struktur [Lit. S. 275 







I 


:: !iS fe != 

" law* is t- 

.4 Ii! Bi liil,; 


Preparation temperature 1600 °C, see Fig. 17a 
Magnetic properties [Ve12, Be32], dielectric prop- 
erties [Be35, Co7], P&S [Szl], see Fig. 17a 
High pressure phase, P&S [Wa5, Vil, Szl] 
Magnetic properties [Ve12, Be 3 2], dielectric prop- 
erties \Be35, Co7], see Fig. 17a 
High pressure phase 

Magnetic properties [Ve12, Be32], dielectric prop- 
erties [Be35, Co7], see Fig. 17a 
High pressure phase 

Magnetic properties [Ve12, Be32, Ro8, Boll], 
dielectric properties [Be3S, Ro8, Bo11, Co7, Isll], 
P& S [Sz1], see Fig. 17a 

High pressure phase 

Magnetic properties [Ve12, Be 3 2], dielectric prop- 
erties [Be35, Co 7], see Fig. 17a 
High pressure phase 


Mi 

I 
1 


% 

Pi 


§1 ii gslllssllsa is is is is is 


s 


ft i 

>- ii ii 

II <«- a 


« •< 


7.647 
3.90 

7.76 
7.694 

7.818 
7.575 
7.557 
7.482 
7.453 
7.432 
7.403 
7.375 
11.43 
11.42 

7.35 
11.41 

7.335 
11.40 

7.32 
11.40 

7.30 
11.37 

7.31 
11.41 


o ■< 






m & mmmm & a a si 1 


I 

v> 




Compound 


1 

ii ii 111 f 1 1 1 1 1 



164 Goodenough/Longo 



Berichtigungen zu Band DI/4a 

S. 177, letzte Zeile: statt BajTdPaO,, lies BajjTbPaO, 

S. 219, Zeile 16 von unten: statt KMg^N^Fej lies KMg^NijF, 

S. 252, Zeile 26 von oben (Uberschrift) : statt Sr,Fe 3 UO, lies Sr,Fe 2 UO, 

Errata in Vol. HI/4a 

p. 177, bottom line: instead of Ba 2 TdPaO e read BajTbPa0 8 

p. 219, line 16 from the bottom: instead of KMg^Ni^Fej read KMg^NijF, 

p. 252, line 26 from above (headline) : instead of Si\,Fe,U0 9 read Sr s Fe e UO, 



Landolt-Bomstein, Neue Serie III /4a 




i i % is Is s s ss sis 35555 3- 



a 

f •* 

- 3 I I si I I II III 1 s HI * 

- 2 I m tlllll m III i I 




3.1 ABX 3 Perowskit-Struktur 



9 ? 



^ii^Wa-^^J-'^fi^^^^lM 5.§§:gS<$| 2 2 8 8 

*$ -is < S <n o * 52. o C-P « ^ (/ j £ o " p«._. t! 3 ft a o, o. 



P3 OOOO OtfoO^OOO oooo 



Goodenough/Longo 



a 


p 


I 


I 
1 

i its ; 

__iJil! I! i 

IfllfffiflHIi l 22 s stssssi 


I 

1 

II 

if 

li 


i 




f 




« -0 


353SS83 illlilllllllSISlllillsss si 




sslill! llllllllllllSSSlsi^lsiS is 


e .< 




i 


_ OOOOOOOOOUOOOOOOOOOOOOOOOOOOOOOOOO OOO 


1 
! 


fiilffiiiifiSliiiilififffiiMii i 



Goodenough/Longo 



3.1 ABX 3 Perowskit-Struktur [Lit. S. 275 



Magnetic 
Data 


in 3.3.4, 
Tab. 


Remarks 


Hex (12 L) 

Hex (12L) 
R perovskite 

Hex (6L), Prep. T> 470 °C 

P&S [St33, Mel 9, CrSa], S.S. with Fe [CrSa] 

P&S[PaW,Me20] 

Prep. [BaO] 

Prep. [BaO] 

P&S [BaS], magnetic properties, fi M = 1.70, 

Structure determined [Bu4a] 
P&S [Sa5] 

Hex (12L) 
Hex (12L) 

Magnetic properties, 80 < T < 300 °K, 
«eff = 2.79, ©p = -14 °K [Fi4] 

Hex (12L) 

Hex (12L) 
P&S[P«2] 

High temperature form 


I 3 




?» 


= s t 

f ! I 




29.76 
. 28.02 
13.754 

7.80 

8.12 
9.45 

8.75 

7.99 
30.40 

28.77 

30.24 

28.61 
8.62 




5.61 
5.81 
5.83 




MMEm 2 25SS2 SSsSi SS I™slss 


1 
en 




Ij 


I — — : 

iiiifetiiiiitai 



Goodenough/Longo 



Ref . p. 

I 

I 
I 



3.1 ABX 3 perovskite structure 



8 II 



g II S II 5 -W 8 II S II c?^ 



?2 ^ P<1 " £ 

§ ii | ii f2vl it g ii n 

A § Jfc S A 



mil 



Goodenough/Longo 



169 



3.1 ABX 3 Perowskit-Struktur 



[Lit. S. 275 



6>Q 

1 




1 

1 


P&S [Bo2] 

Magnetic properties [Ell] 

S.S. with Sr, rhombohedral > 30% Sr 
Cubic > 700 °C 

S.S. with La 

S.S. with x = Pb 2 NbMnO e ; cubic > 50% 


i 


il^ifiiiitf^^^^sssls urn 


f 


II 1 

II II II 
8 8 8 






-° ■< 


2 


« •< 


plSpsiSislSSsSSlllllllllllsSssI MM 


1 


L OUOOOOOUOUOOUOOUUOOOOUOOUOUHOHUO OI*if*iOP3 


1 


iiitaiiiiiiili 



170 Goodenough/Longo 



3. 1 ABX 3 perovskite structure 



I 



I 



111 



i 



i 



1 1 

2 2 ! 

Hi i 



_ 2 



Hiiillll 



9? 



s 

n 





33§3§ 


s 

s 

II 


g 1 




5 


3 S 






O OUOU UOUUOOUOUOUOH 


ooooS 



Mlfi III I 




Goodenough/Longo 



3.1 ABX 3 Perowskit-Struktur [Lit. S. 275 



Magnetic 
Data 


r-i .£> 




P&S [Agl, BrU] 
P&S [Agl] 

P&S[Ga13,Fi10,Ag1] 

P& S [FilO] 
P&S [Gal] 

P&S [Br 16], cubic T > 300 °C [FilO] 
Probably ordered 

Probably ordered, cubic T > 300 °C [FHO] 
P&S [Br16], cubic T > 300 °C [FilO] 
P& S [Br16], cubic T > 300 °C [FilO] 
P&S [BrU] 

P&S [Br 16], fluorescences [BUI, Nil, BI14] 

Probably ordered 

P&S [Br16] 

P&S [Br16] 

P&S [Br 16] 

P&S [BrU] 

P& S [BrU], dielectric properties [Ag1] 
P&S [BrU] 

P&S [Vi3, Ve3], dielectric properties [Vi2b] 
P&S [SI1] 

P&S [BrU] 

P&S [Ku12], cubic T > 200 °C [Ku12] 

P&S[Ga13,Ku12] 

T = 250 °C, cubic T 2: 250 °C 

Cubic T > 630 °C 
P&S [BrU] 


Remarks 


Ref. 




f 


© ° S» 




8.690 
3.980 


o ■< 




e ^ 


8.220 

4.051 

4.090 

4.057 

4.06 

4.1 

8.54 

4.180 

8.17 

8.279 

8.68 

8.607 

4.293 

4.285 

8.540 

8.518 

8.507 

8.496 

4.229 

8.437 

8.434 

8.427 

8.408 

8.374 

8.364 

8.42 

6.086 

7.784 

8.20 

3.965 

7.87 

3.97 

3.960 

3.968 

3.93 

3.9477 

8.34 

5.184 

8.106 


Sym 


OOOOOUOUUOOHOOOOOUUOOOUOOOIlJoOOOSHOOOOOiU 


Compound 





Ref. p. 275] 3.1 ABX 3 perovskite structur? 



Magnetic 
Data 














I 


I 




I 
8" 


S 
H 
g 


P& S [Ku12] 

Slight distortion 
Cubic T > 540 °C 
Cubic T > 540 °C 


I 

ft 


; 

I 

i 


Dielectric properties [Jo-?, 

with Pb(Ti, Zr, Hf)0 3 [/oi], crysl 
Possible rhombohedral distortion 


Defect pyrochlore type 

P&S [Ha32], S.S. with Fe and Pb 




lilllllllliggi Bmmmmmzz m 


s 


n n ii ii ii ii ii 




S3 

°§ 






« •< 


ISssassss s i^IIIIIIflllflf ! 


o •< 


5.94 

5.90 
5.88 
5.87 
5.86 
5.84 












1 




OOOOOOOOOOSSOOOOOOH o 


O O 


1 

8 


\mmsmsam if 



Goodenough/Longo 173 



3.1 ABX 3 Perowskit-Struktur 



[Lit. S. 275 



"5 43 — ^ 



™ ^ * 3 k2 -2 3 * " R 



& 5 £ 



d< QQW&qq <_> O fiiSflPflQ 



S3pH 3 ^ Q5 oq 
2 S >— 1 S >— 5 D5 to 

& £ E W & W ft ft pl, £ 



00 OOOOO o Suoouu 



WW Wooohooh 



PhPmPhPhPhPhPhPl; 



odddd 

9 A *ii < 



174 



Goodenough/Longo 



Ref. p. 275] 3.1 ABX 3 perovskite structure 



"4 


¥ ■■- 


! 

6 


i 1 1 1 3 1 If 1 Is 

< n i : i < ssi s -i a 

I f- J =i Iff ! it i =l { 
I W i t siLiai! us {1 

§ gb a £lss M rssa^ssal 1 222222 12 


i 


3331333- 1 si 533 IllllllllIHsSl 


f 


8 sis § 

8 8 8 8 8 




7.91 

7.99 
7.74 

8.35 








2SS 1 i 11 IS lis Sllllllll!!l2ll 


! 


HOO ooh 0 oSou OO OOP! OiKPiOOOOOOOOOOPiO 


l 

! 


iiiiiiiiiiiiHii 



Goodenough/Longo 175 



3.1 ABX 8 Perowskit-Struktur 



[Lit. S. 275 



Magnetic 
Data 


3g - 


1 
1 


I fill 

• s sill | § !! 

i mi i m Hi i 

Ss rf Js Msgs t t a 11 






i 


©©S>S>©S»©©C) 
II II II II II II II II II II 










«•«: 




1 


I . 


I 

8 


in m^^^m 



176 Goodenough/Longo 



Ref. p. 275] 



3.1 ABX 3 perovskite structure 



1 



if S & I 



III 

imam 



i; 



I ! 



«g«5S§ g SlggSlllSSS 113333333333333 



8l 



linn 



311 



mm- 



si 



~ S— 



I 



S^OOOOUO O oooooo 



OOHoy g ouuu 



OUUUQOOUOOO 



Undoll-Kirnsteiii. Ncue Seric 111/4* 



Goodenough/Longo 



3.1 ABX 3 Perowskit-Struktur [Lit. S. 275 



Magnetic 
Data 




1 
1 


Pu<+ 

P&S [Pa7], Prop. [Ga12, Na4], S.S. with Ba 

and Ca [Ga12], neutron diffraction [Na1 1] 
P&S [Br14] 

Cubic at 320 °C; no dielectric anomaly 

P&S [Br14], semiconducting, LE = 0.78 eV < 

181 °C < 1.30 eV [Nol], S.S. with Ba, cubic at 

22% Ba.[No1,No3] 
Cubic at 230 °C [Ku8. No3], no dielectric anomaly 

Cubic at 420 °C; no dielectric anomaly 


i 




f 






7.909 
7.940 
7.886 

7.966 








lillllllllsasigasss ! mm m I § 
i 


1 


Jo! UOUOOOUUUOOOUOOUOO O OUOOOH HUH O HO 


1 


imifiiiffigii i 



1 78 Goodenough/Longo 



• • 

Ref. p. 275] 3.1 ABX S perovskite structure 


Magnetic 
Data 




Remarks 


1 

P&S [Ba26, Re4a] 

P&S [Ba26], S.S. with Ni [Re4a] 

Optical properties and S. S. with Ba 
Optical properties 

P& S [Be18], dielectric properties [Agl] 
P& S [St32], S.S. with Ni [Re4a] 
No perovskite 

P&S [Br14], Prop., semiconducting, A£ = 0.81 eV 

[Bo1], neutron diffraction [Co31] 
P&S [Br14, Agl], S.S. with Sr [No2], neutron 

diffraction [Co 31], optical properties [Re4a] 
P&S [Ka12, Ve2, Ve3], complete structure [P13] 
P&S [Be18] 

P&S [iu/0, St32], S.S. with Sr,WO e [Bel 8] 

SUghtly distorted; cubic T > 805 °C [Ch4] 

P&S [St 3 2] 

P&S[Be18] 

Distorted 

Composition questionable 
Distorted 

Composition questionable 
P&S [St 3 2], distorted 
Distorted 

Prop. [B14] 
Prop. [B14] 


Ref. 


f^fiS D$ £j ftj ft; 55 i^^^itjit; £ 5q £ 0} $ Co $ ioio ft) $ $ $ $ £$ £3 


.0 -j; 

a 




I 7.70 
| 7.73 

8.465 
7.98 

8.61 


1 5.49 
| 5.53 

5.77 


1 5.36 
1 5.42 

8.13 
8.393 
8.08 
7.94 
7.955 
3.95 
7.680 
5.55 
7.99 

8.099 
8.390 

8.133 
8.098 

8.066 

7.88 

8.116 

8.53 

8.383 

8.62 

8.02 

8.387 

8.29 

8.363 

8.07 

8.38 

7.8 

8.2 

7.82 

8.01 

7.96 


^00 OOOOUOHOU 00 OO O HUUOUOOOUOUOUOUO 


Compound 


isiliiiiiiiiiliii! 



3.1 ABX 3 Perowskit-Struktur 



[Lit. S. 275 



r- , O ^ Ui X 

is'** 



Si 



all ^air^lTJ poll's *sf 



ii i ft" fill ijiii ffff |ff f 



Goodenough/Longo 



3. 1 ABX 3 perovskite structure 



IU * 



„2 SUP g 

ilfflllil { 

' ' " ' || "" p " tit±t2.tit±*M tititiE. tia^S 

pppolppppppopp 




! 
s 

I 

! 



JJJSS S2S222223 33333 33833333 



11 Hi! ii m& Iilillli! 2lssl 



H OOOU OO + UUUUO OOUHUOOHO OOOOO 




Goodenough/Longo 



3.1 ABX 3 Perowskit-Struktur [Lit. S. 275 







Remarks 


i ; 

8 = 
I . 

! ; 


Prop. [S18, Lo2] 

Single crystal [S17], Prep. [Sc/fl 
P&S[S C /S] 

P&S [Lo2, Wa/5] 

P&S [Se/tf] 

P&S [Se/fl 
P&S [Sc/tf] 

P&S [Lo2] 


i 




f 






7.94 
8.21 

7.89 
7.98 
7.92 
8.01 

8.13 

8.16 

7.77 
8.05 
7.86 
7.67 
7.82 
7.69 
7.71 








pill! SsigissssssSsllglllllsssSsss 


1 


+ OOOOOO HOOUOHHHHUHOOOUOOOOOOOOOOOOO 


1 


i«l filliiliill»i!l 



182 Goodenough/Longo 



4 


it ... 


Remarks 


Claim Mn 2 +— Re»+, Prop. [Ro8, Ro11] 
Claim Mn»+-Re 5 + Prop. [Ro8, Ve4] 

Hex (6L) 
Hex (6L) 

Distorted 

Doubtful 

Distorted, P&S [Ru4] 
Ti*+ 

Also prepared as Hex (6L) 
Prop. [DiS] 


i 

f 

* ~n 






7.67 
7.99 
8.024 

14.2 
14.1 

8.72 

8.34 
7.92 

7.92 

8.12 

7.87 
7.66 
7.70 


5.55 
5.77 
5.74 

5.80 
5.47 
5.59 




pm $*$$Mlm$mmm slssssals 


1 


i OOOO OOOKJhOHOOHHOOOOHUHOOOO OOOUOOOOO 


1 


I 

illilllliBlisiiiiiiiiiisflsi 



Goodenough/Longo 183 



3.1 ABX 3 Perowskit-Struktur [Lit. S. 275 



Remarks IMagnetic 
Data 




Optical properties [Re4a] 
Doubtful 

Distorted, P&S [Ru4] 
Distorted 

Hex (6L) 


Distorted 
Ce«+ 

Distorted 

Doubtful 
Doubtful 

Distorted 

Distorted 
Distorted 
Distorted 
Distorted 

Distorted, optical properties [Re4a] 

Complete structure; P&S [SIS, Ru4, Be2S, Ip1] 

Distorted; Prop. [Ke13] 


1 




f 


1 


« ■< 


8.84 

14.9 
8.64 

8.943 

8.46 

8.553 
8.42 

8.36 


~u 


6.13 

6.06 

6.179 
6.03 

6.01 






1 


uhououuKouohuuuooooouoooouuuouooouSouo 


1 

cS 





184 Goodenough/Longo 



Ref. p. 275] 3.1 ABX 3 perovskite structur? 



Magnetic 
Data 


in 3.3.4, 
Tab. 

6 


Remarks 


Complete structure determined, P&S [SIS, Ru4, \ 
Be25, Ipl] 

Not perovskite | 

Not perovskite 

P&S [Ke9] 
P&S [Ke9] 
Distorted, P&S [KeP] 
P&S[Ke9] 

Not able to be made [Wa16] 
S.S. withNa [S14] 

Distorted 

S.S. with Re [SIS] 

Distorted 


Ref. 


£ 1 1 *2 "5 "2 "2 5533 ^ °° °° °° °° °° °° °° °° 10 ^ 
a, to is; tcj Ss| ttj !£j ;< ssss D5 to D5 P5 55 D5 to D5 55 05 D5 K 




II 




8.301 1 
8.21 1 

8.14 




5.958 1 
12.36 | 


« •< 


5.728 1 
13.71 | 

8.799 
8.860 
8.735 
8.780 
8.840 
8.717 

Os'+, I'+ 
8.092 
8.292 
7.84 
8.09 

8.118 
8.296 
7.87 
8.13 
7.83 
8.100 
8.282 
7.86 
8.13 
7.83 
8.33 
8.46 


Sym 


S O £c_>00000 PiOOOH OOOOOO OUUOU 


Compound 


1 £ K 

•B ii 

< 6 £ ^"fifflfflfflBfflm <mmt55ooowmww5om«OT«5o«M 



185 



3.1 ABX 3 Perowskit-Struktur [Lit. S. 275 



Magnetic 
Data 


in 3.3.4, 
Tab. 


! 


P&S [Ga13, B18], see Fig. 1(c) 
See Fig. 1 (c) 

P&S [Ro20, Agl], dielectric properties [SmS], 


Dielectric properties [Ka12, Ve3] 
Cubic > 653 °K 
P&S [Ga1 3, Agl] 

P&S [B18], see Fig. 1 (c) 

P&S [>4g/], optical properties of S.S. with Ba and 

Ca [Re4a], see Fig. 1 (c) 
Prop. [Ve2] 

P&S[Ga13], see Fig. 1(c) 
Distorted perovskite 

Dielectric properties [Sm27, Agl, Ouf, Oula, Ou2, 
BoS, Is4, Bo 16, Be 23, KhS, Kh4, KhS, SmU, 
Sm20, Sm29, Sm8, Cr6b], crystal growth [BaS, 
My 3], electrooptic effect [Sm29] 

No cell dimensions 

Dielectric properties [BoS, Agl] 

Dielectric properties [Ag1, Sm8, BoS, Is4], crystal 
growth [BoS, My 3], S.S. with Mg [Sm20, Sm27, 
SmU, Is4, Cr6b], S.S. with Pb(Ti, Zr)O a [BulO], 
electrooptic effect [Sm29a] 

Dielectric properties [BoS, Kh7, Be23a] 

Dielectric properties [Ve4] 

Dielectric properties [Ve2, Ve3, Ve4] 


I I 




7 

Si 




L 

tM. 

1 — 


7.08 
7.25 

8.40 

8.0 

6.98 
7.16 
4.018 

6.90 ; 

8.148 
6.95 


•O •< 






ESSS! SSiiS32SSi2 M Is JS_ ill 


1 


ffiWooo huouKoHJMhoW hSo oo oo ooo 


I 


fin in if i i 



Goodenough/Longo 







s 


H W-^« operUe,84<r< ' 48 ' K ' 

hS (6L) 
Hex (6L) 

Hex (6L), optical properties of S.S. with Sr and 

Nb [Re4a] 
Hex (6L) 
Hex (6L) 
Hex (6L) 

Optical properties [Re4b] 

Crystal growth [Ga7], see Fig. 1(c) 

P&S [Ga8l crystal growth [Ga7], see Fig. 1 (c) 

See Fig. 1 (c) 

P&S[Ro20l see Fig. 1(c) 

P& S [Ro20], crystal growth[Ga7], optical properties 
^sV^rop^^, VeJ] 

P&S [Gal 3], crystal growth [Ga7], see Fig. 1 (c) 
P&S [Gal 3], see Fig. 1 (c) 

See Fig. 1 (c) 

P&S [Ro20], see Fig. 1(c) 
See Fig. 1 (c) 

P&S [Gal 3], see Fig. 1(c) 

P&S[Ga/i], see Fig. 1(c) 

P, S + Prop. [Ve2, Ve3] 

P&S [Gal 3], see Fig. 1(c) 

Prep. [Agl], electrooptic effect [Sm29a] 

Prep. [Ag1] 


i 




f 






111 3ss sSiSSs II lis s 










1 


X XXXX X MKooooHOOW EWoWW hSBoKuoKSBBhSooo 


| 

3 





Goodenough/Longo 1 87 



3.1 ABX 3 Perowskit-Struktur [Lit. S. 275 



Magnetic 
Data 




Remarks 


i : illl 

I 6 ! !: IP 3 

Ig Is flggl II tit !IC 1 

ult iluiil til Ik l 


1 


33 <3^S^^<3353S3SSSSSSSSSSS§335i 1 5 


f 


ii ii ii ii 

a 8 8 8 




1 7.89 
| 7.87 

14.02 
14.08 

8.642 

11.452 

14.35 
14.08 
14.10 

14.15 

3.951 
10.799 








*5 55§§5i§i3535§Si35lI33! mim % I 


I 


OO KKuouKohoIUSJIoSooooouoo « « H o o o o h 


1 

cS 


iiiiiwnijfeff 



Goodenough/Longo 





Si ...» 


s 

i 






! 


No cell dimensions 

No cell dimensions 

Prop. [V»4. Ro8] 

No cell dimensions 

Dielectric properties [Ve2, Ve4, ViS] 

Dielectric properties [Ve2, Ve4] 

Hex (6L) 

Hex (6L) 
P&S[Ro14] 

Prop. [Be51], S.S. with Sr 3 Fe 2 W0 9 [Se6a\ 


1 








f 




f 






8.138 

8.178 
13.8 
14.10 

14.6 






*> ~t 








« -«« 








i 


O uOSKooooMouoou 


1 


oooouuuooooouo 


i 

, I 

a 


iiiiiiH! 


I 

1 





Goodenough/Longo 189 



3.2 Perowskit-ahnliche Strukturen 



[Lit. S. 275 



3.2 Descriptions of perovskite-related structures 
3.2.1 A-cation vacancies 
3.2.1.1 No A cations 

Because a skeleton of shared-corner octahedra is stable, it is possible to remove all the A cations from 
the perovskite structure without collapsing the BX 3 subarray. In the case of □ ReO, for example, the 
structure remains cubic. However, a partial or a complete collapse of the skeleton is found in many □ BX 3 
compounds. The completely collapsed structure has hexagonal-close-packed X layers with one-third of 
the octahedral sites occupied by B atoms, as indicated in Fig. 19. This results in a simple-cubic array of 
B cations with corner-shared octahedra having a B-X-B angle of 132°. For comparison, Fig. 19 also shows 
the corner-shared octahedra across a close-packed □ X 3 plane of the cubic □ ReO, structure, where the 
B-X-B angle is 180°. It is possible to go from one structure to the other by a simple increase of the B-X-B 
angle, the B cations forming a simple-cubic array in all structures. In the partially collapsed structure, 
represented by CrF 3 , and B-X-B angle is intermediate, 150°. Trifluorides of the first-row transition 
metals have the partially collapsed structure, those of the second- and third-row transition metals have 
the Re0 3 structure where the number of outer d electrons per cation is g 3, but the completely collapsed 
structure where it is ^ 6. The B cations of the latter group either have no atomic moment (Rh m and 
Ir™ have /fg«J) or disproportionate into magnetic and nonmagnetic ions (Pd 2+ , /° g e| and Pd™, so 
that there are no magnetic interactions between neighboring cations. The other trifluorides, on the other 
hand, are all antiferromagnetic, and coupling between like atoms of the second and third long periods is 
stronger than that between like atoms of the first long period . Since the B-X-B superexchange interaction is 
enhanced by a larger B-X-B angle, it is reasonable to assume that the interactions between neighboring 
B cations stabilizes the ReO, structure. These interactions may be either weaker interactions between 
localized electrons, as in the magnetic fluorides, or stronger interactions, as in metallic ReO a . In this 
connection, stabilization of the cubic structure in the tungsten bronzes A£ m W0 3 for mx > 0.3 is signifi- 
cant. The conduction electrons introduce cation-anion-cation interactions while simultaneously reducing 
the energy gained by a ferroelectric distortion. 

Electron-ordering distortions may be superposed on the array of corner-shared octahedra. MnF„ for 
example, exhibits the Jahn-Teller distortions shown in Fig. 10(a) superposed on the partially collapsed 
structure. W0 3 , on the other hand, exhibits several low-temperature phases characteristic of an interplay 
of antiferroelectric distortions and different degrees of the collapse of the B-X-B angle. 

3.2.1.2 The bronze structures 

Although □ BX 3 compounds with the ReO, structure and cubic ABX 3 compounds have the same BX 3 
array, complete solid solutions □ I A,_ I BX 3 , 0 S x g 1, are not possible. Although there is no ordering of 
the vacancies for larger x, except for N^.^WO, [AH], for smaller x there is ordering accompanied by 
a collapse of the BX 3 array within basal planes perpendicular to a unique axis. Such a collapse creates the 
tetragonal and hexagonal tunnel structures of Fig. 20. The tetragonal structure contains three types of 
tunnels, one containing cubic, twelve-coordinated A' sites, one containing pentagonal-prism, fifteen- 
coordinated A " sites, and one small tunnel containing nine-coordinated A'" sites, which are only occupied 
by Li+ ions. Without Li+ ions, all these sites are filled at AJ.jAj'^BX,. This phase, which may occur for a 




Fig. 19. Projections on B-cation planes of two DBX, Fig. 20. Bronze structures found in A-jD^BX, systems, 

structures. Triangles in full and dotted lines represent faces a) Tetragonal (II) structure occurring for * S 0.6. b) Hexagonal 

of octahedra below or above the B-cation plane, a) Cubic structure occurring for x S 0.33 [Wal]. 
□ReO, structure DO,. Arrows indicate cooperative atomic 
motions that collapse the structure, b) Completely collapsed 
□RhF, structure. 



190 



Goodenough/Longt 



Ref. p. 275] 



3.2 Perovskite-related structures^ 



range of x g 0.6, is labelled tetragonal (II) in Tab. 3 to distinguish it from the antiferroelectric tetragonal 
(I) phase of WO s . The hexagonal structure contains hexagonal-prism, eighteen-coordinated A sites and is 
restricted to the range of composition x g 0.33. An orthorhombic tunnel structure has also been identified 
for AB 2 0 6 compounds [GalSa]. 



Tab. 3. Color vs. x for Na^WO, and compositional 
ranges for the bronze structures in the AJ, + W0 3 
perovskites. Adapted from [Di3] 





Fig. 21. Projections onto (110) planes of a) cubic perovskite 
and b) brownmillerite structures. Brownmillerite structure is 
formed by removing alternate [110] strings of oxygen from 
central row of a) and regrouping remaining oxygen into the 
tetrahedra shown in b) [Wat]. 



3.2.2 Anion-deficient compounds 
3.2.2.1 Compounds ABX 3 _,. 

Several systems ABX S _„ where 0 < x < 0.5, have been reported as anion-deficient perovskites. 
SrTiOjj.j and SrV0 2 . 5 , for example, both give simple x-ray powder patterns in qualitative agreement with 
the assumption of a perovskite structure having one-sixth of the anions missing at random. Further, the 
homogeneity range of SrTiO s _ x is reported [ Wa /] to extend over 0 < x < 0. 5 without any change of lattice 
parameter. However, if an anion is removed from a close packed structure, the metal atoms to which it was 
formerly bonded will have highly unsymmetrical coordination, and some local rearrangement of the 
anion can be expected. The nature of this local rearrangement depends upon the character of the B 
cation. In order to learn what rearrangements may occur locally, it is necessary to examine those 
special cases where long-range order occurs, since local changes of cation coordination are difficult to 
detect by x-ray diffraction and have not been investigated by other methods. 

In the system SrFejgFeJi^Os-,, 0 < x < 0.5, it is known that the Fe»+ ions are stable in either tetra- 
hedral or octahedral coordination. Therefore, it is reasonable to anticipate the creation of fourfould co- 
ordination about half of the Fe 3 * ions in the system. This is possible because the d electrons of Fe»+ ions 

localized, so that Fe 3 + and Fe 4 + ions are distinguishable, even though the d electrons of the end member 
SrFe 4 +O s appear to be collective. Support for the creation of tetrahedral sites, as well as a suggestion of how 
the tetrahedra might be arranged, is given by CajFejOs, which has the brownmillerite structure [Be41] of 
Fig. 21. Within every other (001) BX 2 plane of the cubic perovskite, alternate [110] rows of anions are 
removed. The remaining anions in these planes are displaced alternately along [110] and [Tl0] directions 
toward the anion vacancies, the B cations shifting slightly also to maintain equal B-X distances with all 
four near-neighbor anions. The result is fourfold coordination for all B cations in these (001) BX planes, 
sixfold coordination for all B cations in the alternate (001) BX 2 planes. 

The x-ray pattern of KaTijOj has a strong resemblance to that of perovskite. However, KTiO S 5 is not 

anion-deficient perovskite, but is completely ordered, each Ti 4+ ion having five oxygen near neighbors 
forming a trigonal bipyramid [AnJ\. It has little similarity to perovskite. 

The oxygen-deficient, tetragonal compounds (Ba 2I Bi 1 _ 2I )Bi0 3 _ 1 ., 0.22 < x < 0.5, retain an octahedral 
grouping f or Bi in the B sites, but the A positions have only six oxygen near neighbors, two each at 2. 7, 3 . 1 
and 3.6 A [Au1]. 

These examples indicate that a variety of orderings must occur in anion-deficient perovskites. Further 
structural work needs to be done. 



Goodenough/Longo 



191 



3.2 Perowskit-ahnliche Strukturen 



[Lit. S. 275 



3.2.2.2 Alloys M^^Mj 

Since the alloys M C XM| axe generally considered to represent interstitial X atoms in an ordered, face- 
centered-cubic M'Mj alloy, it is not surprising that the phase is stable over a considerable range of anion 
deficiency. Since these alloys are metallic, it is probable that the X-atom vacancies are randomly distri- 
buted. 

3.2.2.3 Shear structures □BO,_ a . 
Ranges of composition have been reported for BOj-*, where B = Mo or W. Magneli [Ma/4] has 
shown that these compositional ranges consist of a series of discrete phases having an x-ray diffraction 
pattern dominated by a cubic □ ReO,-type (DO s ) subcell, but exhibiting superlattice lines. The super- 
lattice of any discrete phase is not due to an ordering of anion vacancies within this basic structure, but to 
a regular interruption of the DO, structure by planes of discontinuity across which octahedra share edges 
rather than corners. In these structures the oxygen vacancies condense into regularly spaced planes and 
are then eliminated by a shear displacement of the type shown schematically in Fig. 22. These "shear" 
planes may be constituted in different ways: For the series of phases BnOjn-j, six octahedra in a group 
share edges, and for the phases BnOj,,-, groups of four octahedra share edges. In both cases the discon- 
tinuities continue in two dimensions throughout the structure where they separate DO„ blocks n octa- 
hedra thick. The fWO s _, phases, 0.10 < x < 0.17, belong to the series B B O s „_ 2 with 12 < n < 20. 
The observed compositional range (W, MoJO,-,, 0.07 < x < 0.12, contains six discrete BbCX^-, phases 
corresponding to n = 8, 9, 10, 11, 12, and 14 [Maf 7a]. The origin of the shear planes appears to be an 
interplay between electrostatic and elastic forces: Electrostatic repulsive energies between B cations 
sharing common octahedral-site edges is minimized by cationic displacements (of ferroelectric type) away 
from the center of symmetry of the interstice and the shared octahedral edge. These displacements can be 
cooperative, costing a minimum of elastic energy, if the shared edges are coplanar. The origin of the 
regular spacing between planes is not established. Presumably it is primarily due to elastic energy, 
although collective-electron effects [Gol 1] probably play a contributing role. 



3.2.3 Structures deficient in B cations 

3.2.3.1 Bismuth compounds 

Bismuth compounds with chemical formula (Bi 2 A m _ 2 )B m _ 1 03 m have the structural formula 
(Bi 2 0 2 ) 2+ (A n _ 1 B„0 3n+ j) 2 -, « = m — 1. These compounds consist of a regular intergrowth of the perov- 
skite structure with Bijj0 2 sheets consisting of Bi0 4 square pyramids sharing edges [Au2], as indicated in 
Fig. 23. Between the Bi 2 0 2 sheets are n layers of corner-shared octahedra and (« — 1) layers of perovskite- 
type A cations in the twelve-coordinated interstices. Where n = 1, the pyramidal sheets alternate with 









1 




X 




X 


X 




1 




X 




X 










1 




X 




X 


X 


; 


1 




1 




X 










1 




%\ 




X 


X 




X 




1 




X 






X 




1 




1 




X 


X 




X 




1 




X 






X 




X 




1 




X 




Fig. 22. Projection onto (001) planes of a) cubic OReO, 
structure and b) B n O,„_, shear plane. Anions are removed 
from black octahedra, which then move to adjacent positions 
form configuration b) [Wal]. 



Fig. 23. One half of the pseudo-tetragonal unit cell of BuTijO,, (from t «. 0.25 
toi~ 0.75). Adenotestheperovskitelayer(Bi ! TijO 10 ) , -,Cthe(Bi,O 1 ) ,+ layers, 
B the unit cells of the hypothetical perovskite s * — ,...r, 




Goodenough/Longo 



Ref. p. 275] 



3.2 Perovskite-related structures 



single octahedral layers, and no sites are available for A cations. This particular phase has been prepared 
in a large number of oxides and oxyfluorides, where B = Ti, Nb, Ta and the O/F ratio depends upon the 
valencies of the A and B cations (see Tab. 4). 

Many of these compounds are reported to exhibit ferroelectric distortions within the perovskite 
layers, and they will certainly be important for technical applications in the future. 

3.2.3.2 Hexagonal A^B^X.,,, structures 
As shown in Fig. 1 (c), the cubic perovskite may be indexed on an hexagonal basis. It consists of cubic 
stacking of close-packed AX 3 layers with B cations in the all-anion octahedral interstices. Within a (110) 
plane, B-cation octahedra share common corners as shown schematically in Fig. 3 (a). In the Ba5Ta 4 0 15 
structure [GaSa], the stacking sequence of the AX S layers is a-b-c-b-c-a, as shown in Fig. 24, and the B-cation 
vacancies are where the stacking is hexagonal. Thus the structure consists of perovskite blocks n AX, 
layers and {n — 1) B layers thick, separated by a stacking fault at a layer of B-cation vacancies. These 
hexagonal structures appear to be stabilized where the tolerance factor is t > 1. 

3.2.3.3 AX • (ABX 3 )„ structures 

Materials having compositions intermediate between ABX S and A 2 BX 4 may have similar diffraction 
patterns. However, this compositional region contains several phases having the structural formula 
AX • (ABX 3 )„. Each phase contains perovskite sheets n units thick separated by AX (NaCl-type) sheets. 
The limiting composition A 2 BX 4 , corresponding to n — 1, is shown in Fig. 25. It is important for the 
theory of magnetism because, if A is nonmagnetic, then by symmetry there is no net molecular field within 
an antdferromagnetic layer from cations in adjacent antifeiTomagnetic layers. This permits the study of 
two-dimensional antiferromagnetism. The A 2 BX 4 structure also permits the study of B 2 + cations in oxides 
with a smaller B-X-B separation (hence stronger interaction) than is found in the BO compounds with 
rocksalt structure. The possible significance of this is illustrated by La^NiO^. The Ni 8 + electrons of e t 
symmetry appear to be collective in LajNiO^ localized in NiO. 



Fig. 24. Schematic (110) projection of the Ba^^Ou str 
ture. Horizontal lines refer to BaO, close-packed layers w 
stacking a, b, or c. 




ABX, AgBXf 
Comparison of ABX, and A,BX 4 structures [Trt]. 



3.2 .4 Data: Crystallographic properties of non-ABX s compounds of composition AJBX S , 
□BX S , (AX)„(ABX) m and Bi 2 O 2 (A n _ 1 B n O 80+1 ) with perovskite-related structure (Tab. 4) 
Tab. 4. 

See Fig. 20(a) for the tetragonal II bronze structure with a m 12.5 A, cw4 A 
and Fig. 20(b) for the hexagonal bronze structure with a 7.4 A, 7.5 A. 



Tab. 4a - A X BX 3 

A x BO s ; B = Nb, Mo, Ta, W, Re 

AjFeFj 
Tab. 4b - □ BX„ 
Tab. 4 c - □ BB'X, 
Tab. 4d - (AX)„(ABX 3 ) ro 

X = F- 1 , CI- 1 ; B s + = Mg, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd 

X = O-*; B = Al, Ti, Cr, Mn, Fe, Co, Ni.Cu, Ga, Ge, Zr, Nb, Mo, Tc, Ru, Rh, Sn, Hf, Ir, Pb, U 
Tab. 4e - Bi 2 0 2 (A n _ 1 B„O jn+ ,) 

n = 1 ; B = Mo, W * = 2; B = Nb, Ta n = 3; B = Nb, Ti n = 4, 5 and 8; B = Ti 



landolt-Bornstein, Ncuc Scrie III/4a 



Goodenough/Longo 



193 

13 



3.2 Perowskit-ahnliche Strukturen 



[Lit. S. 275 



p. 

1 


Magnetic 
Data 


in 3.3.4, 
Tab. 


3 


1 J J !i I 

It iliS 5, 11 11 

fit- tasif ii m 


i 




•i 


s 
1 

II 

8 




g s lis 1! SSSS sggggsls I 




20.5 

7.33 
15.09 
17.81 

3.917 
-< 

3.917 
3.897 
3.915 
3.907 

17.592 




s pips %® i^M § 


I 


O HOUOOO «HO OOOO i-< (-> H H i-< H f-> O H 


1 

(3 


f!li Illlll ! 



194 Goodenough/Longo 



I 



3.2 Perovskite-related structured 



I 



i 

iff 
i {i 

i is 

t t's 

iiii ggssaaajsa ail 



m 

ill 

s Hi 



It 



a 8 Is 



a as Is 



sis llllllilH^ isl gill 



OOON t-> l-< i-> H H h< fr* t-< O t-< fr< i-> O O l-< OOHH W C_> OH 




Good enough/Longo 



3.2 Perowskit-ahnliche Strukturen 



[Lit. S. 275 





¥ 


3 


"Blue Mo bronze"; Prep. [WofO], metallic conduc- 
tivity [Bo20], structural discussion [St22], optical 
properties [Di2a] 

"Red Mo bronze" ; Prep. [WolO]. Semiconducting 
[Bo20], structural discussion [St22] 

High pressure preparation, < 1.3 °K [Sl7a] 

High pressure preparation 


• i 

, MIL 1 : 

i MSllIiiill : 

i^tM^BB I IB B g ; 


i 




53 IS.aaI s**s*3 *3 *3 3 33 33 1 


r 


! \ 




"s • 

s 




i 5 | 


m i m mmtmm mm 


* ■< 


M 5 


t m t 


« •< 


1 § SSs 




I 






hJJ H U O h< O h< h< O O O O 1r< H t-< f-< h> % !r> O f-< ^ t-< lr< l~< I- 1 


1 




lliililii! 



196 



Good enough/Longo 



Ref. p. 275] ^ 3.2 Perovskite-related structur. 



III f ikm t i^i^s p m *« ;t* 

fell? j 1 S^^aall 3l** H ,*lt" & £J^8 i|S 





ffiffitn a Who HWffio hhKoo 



oo 

l" Wo o o" o" 0 - d o" 



Goodenough/Longo 



197 



3.2 Perowskit-ahnliche Strukturen 



[Lit. S. 275 



Still 



ft 

j | h 



! i 

!? it 

-$lzs iiir i nun 



ritj 

i! 



* 1 



is sg §s si s m*m$ m mm 



->OH OH HO H H W HHHOHOOUU OOOO OOOOO 



!i sj t j Bin li n 



Goodenough/Longo 



3.2 Perowskit-ahnliche Strukturen [Lit. S. 275 



ll 


a| ...... .... . 


1 

I 


P&S[EW] 

Neutron diffraction [Wo/i] 

Prop. [BtV, Ha//, Ha/2, Bo33, Ra9], structure 

L/aJ], neutron diffraction [Wo/i] 
300 °.C 

Neutron diffraction [Wot 3], Prop. [Boj?j?, Boi</, 

Neutron diffraction [Wot 3], Prop. [B»7, ShS, Wet 7, 

Neutron diffraction [Wo13], Prop. [He8, ATv/1 
P&S [Mm/] 

P&S[S C 2], "doubtful- 
Neutron diffraction [Wi6], P&S [La7] 
Neutron diffraction 

Neutron diffraction [Wi6], Prop. [Ba/P, Ba20, ATy/, 
Fi3] 

Prep. [Z.o*] 

Prop. [Wy/], "doubtful" 

Structure [Br1, Ta.15], neutron diffraction [Lo6], 
Prop. [Cr7, Otf, Ta15, Co16, Be22, Iw2, De16, 
Ke10], optical properties [Di3a], phase trans- 
formations [Pe3a] 

P&S, [Me11, Bi4, Bi5], crystal growth [Fe21], 
Prop. [S12, Fe21, FelO, Gu6a], structure vs. oxy- 
gen content [S12], DeHaas-Van Alphen effect 
[Ma27a], NMR [Nulla] 

P&S [Ro2] 

P&S [En2] 


& 


u i lissom 11353 11 


i i 

□ s 
4 


V. <Ni ^ — ^ ^ >^ ^ r« r„ r„ r- r„ 

SSBSfiKSooS § 3 £ £ £ £ 00 
SSS £S S~ 3 fiR SXS SS 1 S 

II ll II II II II II II II II II II ll ll ll ll II 

888 88 8«a.8 88 88888 «L 8 




3 i 


•o •< 


1 g 


«xj 


issssl ll i mtM sin II s* 






1 





200 Goodenough/Longo 



Ref. p. 275] W 3.2 Perovskite-related struct! 



Magnetic 
Data 




! 


Structural review [Gi2, Ke11, Co29] 
P&S [Co2P] 

Magnetic properties 80 < T < 300 °K, 
not = 1.66, 0 p = -218 °K [Ha/*] 

P&S[Hw7] 

Magnetic properties, n M = 2.82, 0 p = 31 °K 
P&S [He//], see PdF 8 

P&S [5c22] 


P&S [Co29] 

Magnetic properties 80 < T < 300 °K 
«eff - 0.5, 0 p = -125 [Ha1S] 

P& S [Pe 1] ; magnetic properties 80 < 7" < 300 °K 
«eff = 1.57, 0 P = -100 °K [Hal 9] 


1 


isiis it i nm ii mm 


8 r 

□ 


SSSS o •.'?Sbb 3-vo -o o o S 28 2 o© 

SSS?S S fiSSSS MS 5 S S 

11 II II II II II II II II II II II II II II 1 II II 


■s 








T 


mml 35152 35 3 Mm si mm 




! 


lillii ill II 1 III il fail' 



Goodenough/Longo 201 



3.2 Perowskit-ahnliche Strukturen 



[Lit. S. 275 



Tab. 4d. (AX) n (ABX,) m compounds | 


Magnetic 
Data 




I 


? 1 

I i = !: & s 

li i i M ili « 3 ^ 
H I i m iitiilt- as in 
ii i i m mn® its* lis 


i 


SifesSi §3§S5§a2ll 111 IlllSllstllS 


i 


2 S 

OO CO 

S II 








9.533 

9.354 

7.20 
7.54 
7.47 




mm 5 sggSISSs si! mmam 




1 


b< t-< i-< h< % lr< lr< f-< h f-< i-> 1r> t-> (-< fr< HHH HHHHSHOOOHHH 


I 

8 


iiliiiiii » tails 



202 Goodenough/Longo 



Ref. p. 275] 



3.2 Perovskite-related structures 



II 



13' 



! I . 

L J ! 1 



I 



i Ilfl IB i II III jl j 

M_ a« § « 55a I la ti% MU 11 



I! 



HHHH H HH H H O O H H H H H H H H H H H H H H H H H H H H H H H 



iSisij&ilIlliiiii 



Goodenough/Longo 



3.2 Perowskit-ahnliche Strukturen 



[Lit. S. 275 



Is 




] 


1 

I f J ! I i 

! if U % S, 1 I 

II & S III I? 1 1 1 1 I s ill 

: ! ! ! If! 8 111*1 S ! ssi 


i 


Issaas m 2§§3!!ssi2§sf2«5i«ii§!i 1! 


s 






iiSSSS 111 |ss§ss§iis§ssl|gS|S5gg5g| 










I 


HHHHOHHHHH HhhOHHHHHHHHHHOOHHHHHHHHH H H 


! 


liaililiiiiiiai 



204 Goodenough/Longo 



3.2 Perowskit-ahnliche Strukturen 



[Lit. S. 275 



I* 

H 

i ills. 



I 



i 
III 

If 

IlifiiaCas 



I 

P ft „ 



I 

I! 



mm Mmmm mmmm 



-mm Mil III I 



OOOOOO HOOOOOhOOOHHO HHHHHOHHOOHHO 



ill Sill 



Goodenough/Longo 




377 



BRIEF ATTACHMENT O 



IN THE UNITED STATES PATENT AND TRADEMARK OFFICE 



In re Patent Application of 
Applicants: Bednorz et al. 
Serial No.: 08/479,810 
Filed: June 7, 1995 



Group Art Unit: 1751 
Examiner: M. Kopec 



Date: March 1,2005 



Docket: YO987-074BZ 



For NEW SUPERCONDUCTIVE COMPOUNDS HAVING HIGH TRANSITION 
TEMPERATURE, METHODS FOR THEIR USE AND PREPARATION 



Commissioner for Patents 
P.O. Box 1450 
Alexandria, VA 22313-1450 



In response to the Office Action dated July 28, 2004, please consider the 
following: 



FIRST SUPPLEMENTAL AMENDMENT 



Sir: 



ATTACHMENT O 



Serial No.: 08/479,810 



Page 1 of 5 



Docket: YO987-074BZ 



LANGFNSCH EIDT'S 



DIC » I O NARY 



TWO VOLl'kr*, fff,PNf • 59* CAGES' 



-Till fo£'V:\¥ 



LANGENSCHEIDT'S GERMAN-ENGLISH 
ENGLISH-GERMAN DICTIONARY 
A Washington Square Press edition 

1st printing. . January, 1953 

37th printing August, 1969 

New Revised and Enlarged Edition 
1st printing. January, 1970 

Hiis Washington Square Press edition is published by 
arrangement with Langenscheidt KG, Publishers, Berlin 
and Munich, Germany, and is printed from brand-new 
platts made from newly set, dear, easy-to-read type. 

WSP 

M 

Published by Washington Square Press, 1 
a division of Simon & Schuster, Inc., 630 Fi fth Avenue, New York, N.Y. 

Washington Square Press editions are distributed in the 
U.S; by Simon & Schuster, Inc., 630 Fifth Avenue New 
York, N.Y. 10020 and in Canada by Simon & Schuster 
of Canada, Ltd., Richmond Hill, Ontario, Canada. 
Standard Book Number: 671-47825-7. 
.Copyright ©, J952, 1969, 1970, by Langenscheidt KG, Berlin and 
Munich, Germany. All rights reserved. Published on the same day in 
Canada by Simon & Schuster of Canada, Ltd. Printed in the U.S A 
This Washington Ssuare Press edition may not be sold in Ger- 
many, Switzerland, and Austria. A hard-bound edition of this book 
is available in the U.S. from McGrato-HiU Book Company. 



r 



level-headed 



ne Flache; (gleiche) H6he, Niveau 

n, Stand m; fig. Maflstab m; Was- 

serwaage/; sea - Meeresspiegel m; 

on the - F often, aufrichtig; 3. v/t. 

gleichmachen, ebnen; fig. anpassen; 

richten, zielen mit; - up erhohen; 

v/i. - at, against zielen auf (ace.) J 

--headed vernunftig, nuchtern. 
lever ['li:va] Hebel m ; Hebestange/; 

-age [~arid3] Hebelkraft /. 
levity ['leviti] Leichtfertigkeit /. 
levy I'levi] 1. Erhebung / von Steu- 

ern; JfcJ Aushebung /; Aufgebot n; 

2. Steuern erheben;X ausheben. 
lewd □ [lu:d] liederhch, unzuchtig. 
liability [laia'biliti] Verantwortlich- 

keit /; j% Haftpflicht /; Verpflich- 

tung /; fig. Hang m; liabilities pi. 

Verbindlichkeiten flpl., -f Passiva 

liable □ ['laiabl] verantwortlich; 
haftpflichtig; verpflichtet; ausge- 
setzt (to dat.); be ~ to neigen zu. 

liar ['law] Lugner(in). 

libel ['laibal] 1. Schmahschrift /; 
Verleumdung/; 2. schmahen; ver- 
unglimpfen. 

liberal ['libaral] 1. □ liberal (a. 
pol.); freigebig; reichlich; freisin- 
nig; 2. Liberale(r) m; -ity [liba- 
'neliti] Freigebigkeit /; Freisinnig- 
keit/. 

Uberat|e ['libareit] befreien; frei- 
lassen; -ion [liba'rei/an] Befreiung 
/; -or ['libareita] Befreier m. 

libertine ['liba(:)tain] Wiistling m. 

liberty ['libati] Freiheh /; take 
liberties sich Freiheiten erlauben; 
be at - frei sein. 

librarian [lai'brearian] Bibliothe- 
kar(in); -y ['laibrarij Bibliothek /. 

lice [lais] pi. von louse. 

llcen|ce, Am. -se ['laisans] 1. Li- 
zenz/; Erlaubnis/; Konzession /; 
Freiheit/; Ziigellosigkeit /; driving 
- Fuhrerschein m; 2. lizenzieren, 
berechtigen; et. genehmigen; -see 
[laisan'si:] Lizenznehmer m. 

licentious □ [lai'senjas] unzuchtig; 
ausschweifend. 

lichen flaikan] Flechte /. 

lick [lik] 1. Lecken n; Salzlecke /; 
F Schlag m; 2. (be)lecken; F ver- 
dreschen; Qbertreffen; - the dust 
im Staub kriechen; fallen; geschla- 
gen werden; - into shape zurecht- 

licorice ['likaris] Lakritze /. 

lid [lid] Deckel m; (Augen)Lid n. 

He 1 [lai] 1. Luge /; give s.o. the - 
j-n Lugen strafen; 2. liigen. 

lle» [-] 1. Lage/; 2. [«rr.] liegen; - by 
still-, brachliegen; - down sich nie- 
derlegen; - in wait for j-m auf- 
lauern; let sleeping dogs ~fig. daran 
ruhren wir lieber nichtj --down 
Pai'dauri] Nickerchen n; --in: have 
a - sich grundtich ausschlafen. 

Hen j% ['lian] Pfandrecht n. 



lieu [h'u:]: in of (an)statt. 
lieutenant [lef tenant; & u> t ~ rM 
Am. lu: 'tenant] Leutnant m^ m *i 



tenkaphan m 
life [laif], pi. lives [laivz] Leh^ 1 
Menschenleben n; Lebensbe^f * : 1 
bung /; for „ au f I^Sefef 
one s -, for dear - urns (liebel'rT 1 
ben; to the - naturgetreu- 1 
tence lebenslangUche ZuchtW 1 
strafe; - assurance Lebeasv^" j 
sjcherung /; -belt ['laifbelt] ig' 1 
tungsgurtel m; boat Ret^ J 
boot n; --guard Leibwache 1 
Badewarter m cm Strand; _ S 
ance Lebensversicherung /• | 
jackets Schwimmweste r- w 1 
□ ['laiflis] leblos; matt (a ' I 
^like lebenswahr; -Iongl^ | 
langhch; --preserver Am. fw. J 
pnzarva] Schwunmgunel m; I 

^Le^t/.""'' ' 
lift [lift] 1. Heben n; pky,.,*? Auf . 

tneb m;fig. Erhebung/; FahrstnM f " 

to; give s.o. a - j-m helfen; j- n (im i 

Auto) mitnehmen; 2. »/t. (auf)ae- 1 

ben;erheben;beseitigen;i/.klauen. ' 

stehlen; v/i. sich heben. ; 



lightl [lait] 1. Licht n (a. fig.); Fea . 4 

ster n; Aspekt m, Gesichtspunkt ' 

m; Feuer n; Glanz m; J!;. Leuchte i 

/; -s pi. Fahigkeiten flpl.; will you 1 

give me a - darf ich Sie um Feuer J 

binen; (>ut o - to anzunden; 2. licht, '! 

hell; blond; 3. [»rr.] o/t. o/t ^ up ; 

be-, erleuchten; anzunden; v/i. 

mst - up aufleuchten; - out Am. si. 

schnell losziehen, abhauen. 
light* [-] 1. adj. □ u. adv. leicht ; 

(a. fig.); - current f Schwachstrom '-. 

m; make - of et. leicht nehmen; 

2. - (up)on stoCen o<f. fallen auf 

(ace), geraten an {ace.); sich nieder- 

lassen auf (.dat.). 
lighten ['laitn] blitzen; (sich) erhel- ' 

len; leichter machen; (sich) ei- 

leichtern. 
lighter ['laita] Anziinder m; (Ta- 

schen)Feuerzeug w;^L(e)ichterfn. 
light|-headed ['lait'hedid] win im 

Kopf, ixr; --hearted □ [Jhoaid] . 

leichtherzig; frohlich; -house 

['laithaus] Leuchtturm m. 
lighting ['laitin] Beleuchtung /; 

Anzunden n. 
llghtl-mindedt'lait'maindidlleicht- 

sinmg; -ness ['laitnis] Leichtigkeit 

/; Leichtsinn m. 

lightning ['laitnin] Blitz m; - bug 
Am. so. Leuchtkafer m; --conduc- 
tor, --rod f Blitzableiter m. 

light-weight ['laitweit] Sport: 
Leichtgewicht it. 

like [laik] 1. gleich; ahnlich; wie; 
such - dergleichen; feel - F sich