Poole Ch.P., Jr. Handbook of Superconductivity

376

Chapter 8: Crystal Structures of High-T~ Superconducting Cuprates

Compound a (A) b (A) c (A) T c (K) Ref.

Ba2NdCu408 a . ..... 27.3 57 1

Ba2SmCu408 a 3.872 3.886 27.308 69.3 1

Ba2EuCu408 a 3.8650 3.8837 27.279 68.9 1

Ba2GdCu408 a 3.863 3.881 27.259 73.4 1

BazDyCu408 3.8463 3.8726 27.237 78 2

BazHoCu408 3.8411 3.8694 27.231 80 b 3

B azErCu408 3.8357 3.8668 27.221 83 b 3

BazTmCu408 3.8305 3.8645 27.212 82 b 3

BazYbCu408 3.8213 3.859 27.109 79 c 4

BazYCu408 3.8411 3.8718 27.240 80 5

Ba2Yo.9Cao. 1 Cu408 a 3.841 3.864 27.21 91 6

BazYo.6Pro.4Cu408 3.8614 3.8807 27.260 65 d 7

a Nominal composition.

b From resistivity measurements (midpoint).

c Value taken from figure.

d From resistivity measurements; value taken from figure.

References: 1, Morris

et al. (1989); 2, Hazen et al. (1989); 3, Moil et al. (1994); 4, Hijar et aL (1995);

5, Fischer

et al. (1989); 6, Miyatake et aL (1989); 7, Berastegui et aL (1992).

2212 T12Ba2Cal

Cu208

AzB2CD20 8, tI30, (139) I4/mmm-ge5a

-DO 2-. C-DO2-OB-A O-OA-BO-

TlzBazCaCu208, T c -- 110 K, SX, RT, R w = 0.018

(Subramanian et aL, 1988a)

(139)

I4/mmm a = 3.8550, c = 29.318A, Z = 2 Fig. 24

H. Crystallographic Data Sets 377

Atom WP PS x y z

Occ.

T1 4(e)

4ram

0 0 0.28641

1 1 0.37821

Ba 4(e)

4mm ~

Cu 4(e)

4ram

0 0 0.4460

1 1 1

Ca 2(a)

4/mmm ~ ~

1

0.2815

O(1) 16(n) .m. 0.396

0(2) 4(e)

4ram

0 0 0.3539

1 0.4469

0(3) 8(g)

2mm . 0

0.25

Compound a (A) c (A) T c (K) Ref.

T12Ba2CaCu208 3.8550 29.318 110 1

Hgl.sBa2Prl.3Cu2.208_

6

3.9236 28.993 n.s. 2

Hg2Ba2YCuzO7.55 a

3.8606 28.915 n.s. 3

Hg2Ba2Yo.sCao.sCu208_6 b ...... 45 3

Hg 1.4Tlo.6Ba2Yo.6Cao.4Cu207.78 c 3.86 a 29.05 a 84 4

a

Prepared at 1.8 GPa.

b Prepared at 1.8 GPa; nominal composition,

c Prepared at 5 GPa; nominal composition, oxygen content from chemical analysis.

a Value taken from figure.

References: 1, Subramanian

et al.

(1988a); 2, Martin

et al.

(1995); 3, Radaelli

et al.

(1994b); 4,

Tokiwa-Yamamoto

et al.

(1996).

2212

(Pbo.5oCuo.5o)2(Bao.5oSro.5o)2(Yo.8oCao.2o)lCU207

A2B2CD206+6,

ti26, (139)

I4/mmm-ge4(e)a

-002--.

C-D02-OB-A .(A 0 )-.A ( OA )-BO-

PbBaSrYo.sCao.zCu307, Tc -- 39 K, a PN, RT, R 8 -- 0.0645

(Ishigaki

et al.,

1994)

(107)

I4mm,

a = 3.83673, c -- 27.5098 A, Z -- 2 Fig. 25

al, a2, C

378

Chapter 8: Crystal Structures of High-Tr Superconducting Cuprates

Atom WP PS x y z Occ.

Pb

s?

r

yr

Cu(2)

Ba a

Cu(3)

o(1)

0(2)

0(3)

o(4)

0(5)

2(a)

4mm

0 0 0.2804

1 1 0.3751

2(a)

4mm ~

2(a)

4mm

0 0 0.4423

1 1 0.5

2(a)

4mm ~

2(a)

4mm

0 0 0.5626

1 1

0.6340

2(a)

4mm ~

2(a)

4mm

0 0 0.7154

1

0.2810

8(d) .m. 0.382

2(a)

4mm

0 0 0.3537

1

0.4510

4(b)

2mm . 0

1 0.5564

4(b)

2mm . 0

2(a)

4mm

0 0 0.6501

0.25

a

From resistivity measurements.

b Sr -- Sro.65Bao.35.

c y __ Yo.8Cao.2.

dBa = Bao.65Sro.35.

Compound a (A) c (A) T c (K) Ref.

PbBaSrYo.8Cao.2Cu307 3.83673 27.5098 39 a 1

PbBaSrYo.8Cao.2Cu308.35 3.84413 27.8036 n.s. 1

a

From resistivity measurements.

Reference: 1, Ishigaki

et al.

(1994).

2212

(Bio.93)2(gro.88Bio.04)2(Cao.96Bio.04) 1 Cu208

A2B2CD20 s,

tI30, (139)

I4/mmm-geSa

-DO2-.C-DO2-OB-A O-OA-BO-

Bil.98Srl.75Cao.96Cu208, a T c -- 92 K, PN, 6 R B = 0.060 (Gao

et aL,

1993; Petricek

et al.,

1990)

(37)

A2aa (Ccc2),

a = 5.4150, b = 5.4149, c = 30.861 A, c Z = 4

a 1 + a 2, -a 1 + a 2, e; origin shift 0 ~ ]

Atom WP PS x y z Occ.

Bi 8(d) 1 0.004 0.2333 0.0523

Sr a 8(d) 1 0.5 0.2527 0.1408

Cu 8(d) 1 0.0 0.2502 0.1966

1 1

Ca e 4(c) 2.. 0.5 ~

O(1) 8(d) 1 0.53 0.151 0.0571

0(2) 8(d) 1 0.01 0.277 0.1163

0(3) 8(d) 1 0.25 0.5 0.1980

0(4) 8(d) 1 0.25 0.0 0.1983

0.93

0.915

a Composition Bi2.08Srl.s2Cao.soCu208 from SX refinement; extra 0.14 O atoms per formula unit

found from refinement in 4D superspace group a,cA2aa

....

1 1 1, q = 0.2095a* (located in the BiO layers).

b Coordinates from combined PN and SX refinement.

c Average structure, additional reflections indicate incommensurate modulation (q = a*/4.773).

d Sr -- Sro.956Bio.044.

e

Ca -- Cao.96Bio.04.

(continued)

H. Crystallographic Data Sets 379

Compound a (A) b (A) c (A) T c (K) Ref.

Bil.98Srl.75Cao.96Cu20 8 5.4150 5.4149 30.861 a 92 1

Bil.6Pbo.4Sr2CaCu208+6 b 5.363 c 5.404 ~ 30.69 c'a 95 2

Bi1.97Pbo.o8 Sr1.83 Cao.72Ero.56Cu208+6 b 5.44 5.44 30.360 82 3

Bi1.79Pbo.11Srl.78Cao.74Ybo.44Cu208+6 b 5.41 5.41 30.554 60 3

Bi2Srl.5Cal.25Yo.25Cu208.25 b 5.405 c 5.403 C 30.48 c'e 86 f 4

BizSr2YCu208.5 b 5.428 5.465 30.175 g n.s. 5

a

Additional reflections indicate incommensurate modulation (q = a*/4.773).

b Nominal composition.

c Value taken from figure.

d Additional reflections indicate incommensurate modulation (q ~ a*/5.8).

e Space group Amaa.

fFrom resistivity measurements (midpoint).

g Additional reflections indicate superstructure (8a, b, c).

References: 1, Gao et al. (1993); 2, Fukushima et al. (1989); 3, Ilyushin et al. (1993); 4, Manthiram

and Goodenough (1988); 5, Tamegai et al. (1988).

2212

(Bio.60Pbo.40)2Sr2(Yo.60Cao.40) 1 Cu208

A2B2CD208, tI30, (139) I4/mmm-geSa

-DO2-. C-DO2-OB-A O-OA-BO-

Bil.zPbo.sSrzYo.6Cao.4Cu208, T c = 75 K, a SX, R - 0.065 (Calestani et al., 1992)

(52) Pnan (Pnna), a = 5.374, b = 5.421, c = 30.397 A, Z = 4

a 1 + a 2, -a 1 + a 2, c; origin shift 0 1 1

Atom WP PS x y z

Occ.

Bi b 8(e) 1 -0.0100 0.2335 0.0492

Sr 8(e) 1 0.4715 0.2508 0.1371

Cu 8(e) 1 -0.0257 0.2502 0.1958

1 1

Y~ 4(d) 2.. 0.4764 ~

O(1) 8(e) 1 0.616 0.152 0.053

O(2) 8(e) 1 -0.042 0.275 0.117

O(3) 8(e) 1 0.224 0.019 0.199

O(4) 8(e) 1 0.228 0.484 0.202

aT c

(from resistivity measurements, value taken from figure) given for Bil.2Pbo.8Sr2Yo.4Cao.6Cu208

(nominal composition).

6 Bi = Bio.6Pbo. 4.

y = Yo.6Cao.4.

Compound a (A) b (A) c (A) T c (K) Ref.

Bil.2Pbo.8Sr2YCu208 5.388 5.423 30.367 n.s. 1

Bil.2Pbo.sSr2Yo.4Cao.6Cu208 a 5.362 b 5.412 b 30.50 b 75 b'c 1

a Nominal composition.

b Value taken from figure.

c From resistivity measurements.

Reference: 1, Calestani et al. (1992).

Ba2YCu408 (Cu-2212) was first considered as planar defects in

Ba2YCu307_ 6

and structural models (space group

Ammm)

based on the insertion

380

Chapter 8: Crystal Structures of High-Tc Superconducting Cuprates

of an extra AO' (CuO) layer imo the structure of Cu-1212 were proposed

(Zandbergen

et al.,

1988b,c; Marshall

et al.,

1988). The first refinement was

carried out on diffraction data from a superconducting film (T c = 80 K) (Marsh

et

al.,

1988). Bulk synthesis of Ba2RCu408 compounds were reported for R = Y

(Karpinski

et al.,

1988b) and R = Y, Nd, Sm-Gd, Dy-Tm (Morris

et al.,

1989).

Subsequent structural refinements (Hazen

et al.,

1989; Fischer

et al.,

1989)

confirmed the structure proposed by Marsh

et al.

(1988). In contrast to the Cu-

1212 compounds, Cu-2212 compounds do not display a variable oxygen content.

A significant enhancement of the superconducting transition temperature was

observed at high pressure (T c = 108 K at 12 GPa) (Van Eenige

et al.,

1990).

Superconductivity in the T1-Ba-Ca-Cu-O system was first reported by

Sheng and Hermann (1988b). A T1-2212 compound, T12Ba2CaCu208+~, was

identified by Hazen

et aL

(1988a), and its structure was refined by Subramanian

et

aL

(1988a). In the majority of the structural studies reported up to now, the Ca site

was found to be occupied by mixture of Ca and T1 (12-28 at.% T1), whereas the

reduced scattering of the T1 site was attributed to either a partial substitution of T1

by Ca (10-11 at.%) (Maignan

et aL,

1988; Kikuchi

et aL,

1989; Johansson

et aL,

1994) or Cu (9 at.%) (Onoda

et al.,

1988); or simply to vacancies (occupancy

0.87-0.94) (Morosin

et aL,

1991a; Ogbome

et aL,

1992b; Molchanov

et al.,

1994). Vacancies on the O site in the

additional

layers were detected by Ogbome

et al.

(1992b) and Johansson

et al.

(1994) (occupancy 0.94-0.95 or 0.84-0.88),

whereas a displacement of the T1 site from the ideal position

(32(0) 0.013 0.041 0.28635) was considered by Molchanov

et aL

(1994).

A (Pb,Cu)-2212 compound was first reported for the composition

PbBaYSrCu308 (Rouillon

et aL,

1989). Ca-free, reduced (PbSrBaYCu307) and

oxidized (PbSrBaYCu308.2) compounds were also prepared, and structural

models were proposed (Tokiwa

et aL,

1989). Superconductivity was observed

for reduced, Ca-containing PbSrBaYo.yCao.3Cu307 (T c = 55 K) (Tokiwa

et aL,

1990a). The first structural refinement, carried out on the reduced, Ca-flee

compound (Rouillon

et aL,

1992a), was later confirmed by a refinement on a

Ca-containing compound (Ishigaki

et al.,

1994). In the latter article, the structure

of oxidized PbSrBaY0.gCa0.zCu308.35 was also reported. An ordered arrangement

of PbO and Cu layers was observed for the reduced compounds, whereas a close

to statistical occupation of the cation sites in the

additional

layers (45 at.% Pb and

55 at.% Cu, and vice versa) and four partly occupied O sites were found for the

oxidized compound.

Superconductivity in the Bi-Sr-Ca-Cu-O system was first reported for a

sample of composition BiSrCaCuzOy, which contained two superconducting

phases (T c = 75 and 105K) (Maeda

et aL,

1988). Studies on a sample of

composition BiSrCaCuO7_ ~ gave similar results (Chu

et al.,

1988). The super-

conducting compound with the lower critical temperature was identified as Bi-

2212 (Tarascon

et al.,

1988), and an orthorhombic subcell (a= 5.439,

b = 5.410, c = 30.78 A) and a 5-fold superstructure (5a, b, c) were proposed

(Hazen

et aL,

1988b). The first refinements were carried out in space group

H. Crystallographic Data Sets 381

I4/mmm

(a = 3.814, c = 30.52 A) (Tarascon

et al.,

1988; Torrance

et al.,

1988),

Fmmm

(Sunshine

et al.,

1988; Kajitani

et al.,

1988; Bordet

et al.,

1988a) or

Amma

(Subramanian

et al.,

1988c,d; von Schnering

et al.,

1988; Imai

et al.,

1988), the structure showing an incommensurate modulation in the direction

[1 0 0] of the orthorhombic cell ([1 1 0] for the tetragonal cell) with a

translation period of approximately 5 times a. The main differences between

the proposed structures concern the positions of the oxygen atoms in the

additional

layers, the earliest models containing oxygen atoms between Bi

layers, based on the similarity with the Aurivillius phases, known since 1950

(Aurivillius, 1950). In the model described in the noncentrosymmetric space

group

A2aa

by Bordet

et al.

(1988b), the oxygen atoms were significantly

displaced from the ideal position in order to approach Bi-O distances of ~ 2.2 A.

Partial substitution of Ca site by Bi was reported by Sunshine

et al.

(1988)

and Imai

et al.

(1988) (20 and 6at.%, respectively), whereas a considerable

homogeneity range with respect to the Sr/Ca ratio has been mentioned in almost

all articles. The translation period of the modulation vector, expressed as a

multiple of the a-parameter of the orthorhombic cell, was shown to be approxi-

mately constant within the Sr-Ca homogeneity range (Niu

et al.,

1989). The same

translation period progressively decreased to ~ 4, when Ca was substituted by a

trivalent rare-earth element, the orthorhombicity

(b/a)

being increased at the

same time (from x -- 0.5 for BizSr2Cal_xYxCu208+,5 , Figs. 8.39 and 8.40).

Refinements of the incommensurate structure of Bi-2212 were carried out

in 4D superspace group

ll/fAmaa

by Gao

et al.

(1988) and Yamamoto

et al.

(1990),

''-1 1 1

Fig. 8.39.

30.9

30.8

' I ' I ' I '

30.7

3o.s

30.4 ~-

2

~:~ 5.46

-- o a

~ 5.44~

~') 5.42

5.40 ~..-.-~

5.38 I

0.0 0.2 0.4 0.6 0.8 1.0

x in

Bi2Sr2Cal_xYxCU208+ 6

Cell parameters vs Y content for

Bi2Sr2Cal_xYxCu208+ 6

(Niu

et al.,

1989).

382

Chapter

8:

Fig. 8.40.

Crystal Structures of High-Tc Superconducting Cuprates

5.0

' I '

i

' I '

I

"'

4.8

4.6

"~ O

O

"" ~O

4.4 -

~0 4.2-

m o

=

4.0

9

3.8

-

3.6

, I , i .... I , I , I i

0.0 0.2 0.4 0.6 0.8 1.0

x

in Bi2Sr2Cal_xYxCU208+a

Translation period of the modulation vector vs Y content for Bi2Sr2Cal_xYxCu208+ 6 (Niu

et

al.,

1989).

whereas the noncentrosymmetric

group

MA2ala 1

was preferred in Petricek

et al.

(1990) and Gao

et al.

(1993). In the last two articles, a saw-shaped function was

used to describe the displacements of the oxygen atoms in the

additional

layers

and extra O atoms were found. Several refinements in supercells were performed,

approximating the modulation period to an integer multiple of a. The apparently

truly commensurate structure of the Fe-containing compound BiloSr15FeloO46

was refined in a 5-fold supercell (B222, a = 27.245, b = 5.4617, c = 31.696 A),

considering one extra oxygen atom per formula unit in the BiO layers (LePage

et

al.,

1989). Calestani

et al. (1989)

and Levin

et al.

(1994) refined the structure of a

cuprate in a primitive cell

(Pnnn)

of the same volume, whereas Beskrovnyi

et al.

(1990a,b) used a 19-fold supercell, approximating the translation period of the

modulation vector to 4.75a. In the last three articles, extra O sites and vacancies

on some Sr sites were reported. A monoclinic variant of Bi-2212 with a 9-fold

supercell (Bi2.09Srl.90Cal.ooCu208.22,

Cc,

a = 37.754, b = 5.4109, c =

41.070 A, fl = 103.58 ~ was refined by Gladyshevskii and Fliikiger (1996), the

monoclinic symmetry corresponding to a systematic shift of the modulation

waves of consecutive

additional

layers by re/9.

Studies on the substitution of Bi by Pb showed that the periodicity of the

structural modulation increases with increasing Pb content and becomes infinite

(no modulation) for a high Pb content (Fukushima

et al.,

1989). Modulation-free

structures with the composition

Bi2_xPbxSr2Yl_yCayCu20 z

were reported to exist

H. Crystallographic Data Sets 383

Fig. 8.41.

"Ja U "")

L I

'Ill I I ' ' I III

I

'

I

'

30.4 1 ~ ~ ....

c

}.2

5.44

b

5.42 ,~-----~--..O~

)

- b

I:~ 5.40 -

5.38 - a _

5.36 i ! )

0.0 0.2 0.4 0.6 0.8 1.0

x

in B iz_xPbxSrzYo.6Cao.4Cu208+ a

Cell parameters vs Pb content for Bi2_xPbxSr2Yo.6Cao.4Cu208+ a (Calestani

et al.,

1992).

in the region x = (1 -y/2)

4-

0.2 (for 0 < y < 0.8) (Calestani

et al.,

1992). The

structures, refined in space group

Pnan,

revealed large orthorhombic distortions

(Fig. 8.41) and an arrangement of the BiO ribbons different from that observed

for Pb-free Bi-2212, the BiO chains in consecutive

additional

layers being here

directly "superimposed," whereas in the structure of Pb-free Bi-2212 they are

mutually shifted by a/2.

384 Chapter 8:

2222

Crystal Structures of High-T~ Superconducting Cuprates

Bi2Srz(Gdo.85Ceo.15)2Cu2Olo

AzBzC2DzOlo, tP18, (129) P4/nmm-fc6b

-0 2D--C.-O2-.

C-DO2-OB-A O-OA-BO-

Bi2SrzGdl.7Ceo.3Cu2Olo, a T c = 25 K, PX, R e = 0.0780

(Tokura

et aL, 1989a)

(67)

Cmma, a = 5.4445, b = 5.4573, c = 17.913 A,

Z--2 Fig. 26

a 1 + a2, --a 1 + a2, e;

origin shift 88 88 0

Atom WP PS x y

z Occ.

1 0.0854

Bi 4(g)

mm2 0

1 1

0.234

Sr 4(g)

mm2 ~

1 0.336

Cu 4(g)

mm2 0 -4

1 1

0.4311

Gd b 4(g)

mm2 ~ -4

1 1

0.090

O(1) 4(g)

mm2 ~

1 0.212

O(2) 4(g)

mm2 0

1 0

0.341

0(3) 8(/) . .2

1 0 1

0(4) 4(b) 222 ~

a Oxygen content Bi2Sr2Gdl.7Ceo.3Cu2Olo.24 from chemical analysis (extra oxygen atoms probably

located in the BiO layers).

b Gd = Gdo.85Ceo.15.

Compound a (/~) c (A) a T c (K) Ref.

T12Ba2EUl.8Ceo.zCuzO 10+6

Pbo.95Bao.77Srl.23PrCeCu309

Bi2Sr2Prl.64Ceo.36Cu2Olo.27

c

Biz Sr2Nd

1.64Ce0.36Cu2010.23 c

Bi2Sr2Sml.64Ceo.36Cu2 O10.24 c

BizSrEEUl.64Ceo.36Cu2Olo.26

c

Bil.zPbo.8Sr2EUl.8Tho.2Cu2Oy

B i2Sr2Gd

1.64Ceo.36Cu2010.24 c

Bi2SrzTb1.64Ceo.36Cu2Olo.26

c

Bi2SrzDyl.64Ceo.36Cu2Olo.26

c

Bi2Sr2Ho 1.64Ceo.36Cu2010.22 c

BizSrzEr1.64Ceo.36Cu2Olo.21

c

3.888 17.281 n.s. 1

b n.s. 2

3.885 17.87 n.s. 3

3.881 17.93 14 3

3.863 17.90 16 3

3.854 17.88 27 3

d 15 4

3.851 17.88 34 3

3.847 17.83 n.s. 3

3.844 17.87 27 3

3.840 17.86 24 3

3.837 17.84 n.s. e 3

(continued)

H. Crystallographic Data Sets 385

Bi2 Sr2 Tm 1.64Ceo.36Cu201 o.2o c

Bi2SrzY1.64Ceo.36Cu201o.22 e

Hg 1 .sB azPr2.3 Cu2.201 o-~

3.827 17.84 n.s. e 3

3.836 17.85 20 3

3.9072 17.2192 n.s. 5

a Space group

P4/nmm.

b Space group

Cmm2,

a -- 5.4703, b = 5.4816, and c -- 16.4017 A.

C Nominal composition, oxygen content from chemical analysis.

d Orthorhombic; a -- 5.430, b = 5.466, and c -- 18.00 A.

e Superconductivity not observed above 5 K.

References: 1, Tokura

et al.

(1989a); 2, Rouillon

et al.

(1992b); 3, Arima

et al.

(1990); 4, Sasakura and

Yoshida (1996); 5, Huv6

et al.

(1995).

Bi and T1-2222 were first reported by Tokura

et al.

(1989a).

TlzBa2EUl.8Ceo.zCu2010+6 crystallizes with a tetragonal structure

(P4/nmm)

and is not superconducting. The average structure of BizSrzGdl.vCeo.3Cu2010+6

is the same; however, distortions similar to those described for Bi-2212 lead to an

orthorhombic structure. Extra oxygen atoms (6 -- 0.24) were postulated to reside

in the BiO layers. A series of nonsuperconducting PbBao.7Srl.3CeRCu309

compounds

((Pbo.sCuo.5)z(Bao.35Sro.65)z(Ceo.sRo.5)zCu209,

R : Sm, Eu, Gd,

Dy, Ho, Er and Tm) were reported by Tokiwa

et al.

(1990b). A structural

refinement on Pbo.95Bao.77Srl.23PrCeCu309 in space group

Cmm2

showed an

ordered arrangement of PbO and Cu layers (Rouillon

et al.,

1992b).

2223

A2B2C2D301o ,

ti38, (139)

I4/mmm-ge6cb

-D02-.

C-D02-. C-DO2-OB-A O-OA-BO-

T11.94BazCa2.o6Cu3Olo, T c : 125 K, SX, RT,

R w

-- 0.074

(Torardi

et al.,

1988b)

(139)

I4/mmm,

a = 3.8503, c - 35.88 A, Z = 2 Fig. 27

(Tlo.8 5Cao.

15)2Ba2(Cao.88Tlo. 12)2 Cu3 O 10

Poole Ch.P., Jr. Handbook of Superconductivity

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