New high-T/sub c/ superconductor containing thallium and its crystal structure: the 1212 phase (Tl/sub 1-x/Bi/sub x/)/sub 1. 33/Sr/sub 1. 33/Ca/sub 1. 33/Cu/sub 2/O/sub 6. 67 + delta/

Journal Article · Wed Jun 01 00:00:00 EDT 1988 · J. Superconduct.; (United States)

DOI:https://doi.org/10.1007/BF00617665· OSTI ID:5929674

Haldar, P; Sridhar, S; Roig-Janicki, A; Kennedy, W; Wu, D H; Zahopoulos, C; Giessen, B C

Joining YBa/sub 2/Cu/sub 3/O/sub 6.5 + delta/ (123 phase) and Bi/sub 4/Sr/sub 4/Ca/sub 2/Cu/sub 4/O/sub 16 + delta/ (4424 phase) as structurally characterized high-T/sub c/ superconductors, the thallium-containing superconductor (Tl/sub .75/Bi/sub .25/)/sub 1.33/Sr/sub 1.33/Ca/sub 1.33/Cu/sub 2/O/sub 6.67 + delta/ with the ideal stoichiometry (Tl, Bi)/sub 1/Sr/sub 2/Ca/sub 1/Cu/sub 2/O/sub 6.5 + delta/ (1212 phase) is reported here. As prepared from the component oxides, 1212 has an initial deviation from resistance linearity at 120 K, a superconducting onset temperature of 92 K, and zero resistance at 75 K. The tetragonal unit cell (P4/mmm, a = 3.800 /angstrom/; c = 12.072 /angstrom/, deduced from powder data) contains double copper oxygen sheets (like 4424 and 123) that alternate with single thallium-bismuth oxygen sheets (in contrast to 4424, which contains double bismuth oxygen sheets), resulting in a total of three stacked perovskite-like cells (as in 123). The copper oxide sheets (with intersheet spacing 3.38 /angstrom/) are separated by Ca/sup 2 +/ and the Cu oxide sheets and (Tl, Bi) oxide sheets (with spacing 4.35 /angstrom/) are separated by Sr/sup 2 +/, Ca/sup 2 +/, and excess (Tl, Bi)/sup 2 +/. The 1212 cell constitutes the building block for the centered, more complex 4424 cell. The 1212 structure persists to Bi contents as low as 1% and can also be stabilized by Pb instead of Bi; Tl cuprates also from other superconductors with lower T/sub c/.

• Research Organization: Northeastern Univ., Boston, MA (USA)
• OSTI ID: 5929674
• Journal Information: J. Superconduct.; (United States), Vol. 1:2
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BISMUTH OXIDES
SUPERCONDUCTIVITY
CALCIUM OXIDES
COPPER OXIDES
STRONTIUM OXIDES
SUPERCONDUCTORS
CRYSTAL STRUCTURE
THALLIUM OXIDES
BISMUTH
CERAMICS
LATTICE PARAMETERS
METALLURGICAL EFFECTS
POWDER METALLURGY
SPACE GROUPS
STOICHIOMETRY
TETRAGONAL LATTICES
THALLIUM
TRANSITION TEMPERATURE
X-RAY DIFFRACTION
ALKALINE EARTH METAL COMPOUNDS
BISMUTH COMPOUNDS
CALCIUM COMPOUNDS
CHALCOGENIDES
COHERENT SCATTERING
COPPER COMPOUNDS
CRYSTAL LATTICES
DIFFRACTION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
METALLURGY
METALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SCATTERING
STRONTIUM COMPOUNDS
THALLIUM COMPOUNDS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
360202* - Ceramics
Cermets
& Refractories- Structure & Phase Studies
360204 - Ceramics
Cermets
& Refractories- Physical Properties