Crystal structure and superconductivity of TlBa/sub 2/Ca/sub 3/Cu/sub 3/O/sub 8. 5/

Journal Article · Mon May 01 00:00:00 EDT 1989 · Modern Physics Letters B; (USA)

DOI:https://doi.org/10.1142/S0217984989000881· OSTI ID:5525284

Liang, J K; Zhang, Y L; Huang, J Q; Xie, S S; Che, G C; Cheng, X R; Ni, Y M; Jia, S L ^[1]

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1. Institute of Physics, Chinese Academy of Sciences, Beijing (CN)

The crystal structure of TlBa/sub 2/Ca/sub 2/Cu/sub 3/O/sub 8.5/(T/sub c/ = 112 {Kappa}) has been determined by means of X-ray powder diffraction method. It belongs to primary tetragonal symmetry with lattice parameters: a = 3.847 A, c = 15.89 AT. Its space group is D/sub 4h//sup 1/-P4/mmm. Each unit cell contains one chemical formula unit. The arrangements of ions in a unit cell are as follows: 1T1 cation occupies 1(b) equivalent point position. 2Ca and 2Ba cations occupy 2(h) equivalent point positions with respective atomic parameters z = 0.100 and 0.320. 3Cu occupy 1(a) and 2(g) (z = 0.200) equivalent point positions. 8.50 anions occupy 1(d), 2(f), 2(g) (z = 0.325) and 4(i) (z = 0.200) equivalent point positions respectively. (Occupation factor is 0.945.) The crystal structure of TlBa/sub 2/Ca/sub 2/Cu/sub 3/O/sub 8.5/ is quite similar to those of the other superconducting phases. All cations are distributed at positions of (0,0,z) and (1/2,1/2,z) alternatively. The oxygen deficient pseudo-perovskite unit Ba-Cu-Ca-Cu-Ca-Cu-Ba is separated by double Tl-O layers in the crystal structure of Tl/sub 2/Ba/sub 2/Ca/sub 2/Cu/sub 3/O/sub 10/. However, the oxygen deficient pseudo-perosvkite unit Ba-Cu-Ca-Cu-Ca-Cu-Ba is separated by single Tl-O layer in the crystal structure of TlBa/sub 2/Ca/sub 2/Cu/sub 3/O/sub 8.5/. The relations among the crystal structure of the superconducting phases as well as the relation between the crystal structure and superconductivity are discussed.

• OSTI ID: 5525284
• Journal Information: Modern Physics Letters B; (USA), Journal Name: Modern Physics Letters B; (USA) Vol. 3:7; ISSN 0217-9849; ISSN MPLBE
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
360204 -- Ceramics
Cermets
& Refractories-- Physical Properties
656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
COHERENT SCATTERING
COPPER COMPOUNDS
COPPER OXIDES
CRYSTAL STRUCTURE
DIFFRACTION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
LATTICE PARAMETERS
MINERALS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PEROVSKITE
PEROVSKITES
PHASE STUDIES
PHYSICAL PROPERTIES
POWDERS
SCATTERING
SUPERCONDUCTIVITY
SUPERCONDUCTORS
THALLIUM COMPOUNDS
THALLIUM OXIDES
TITANIUM COMPOUNDS
TITANIUM OXIDES
TRANSITION ELEMENT COMPOUNDS
X-RAY DIFFRACTION