Two-zone equilibria of Tl-Ca-Ba-Cu-O superconductors

Journal Article · Sat Jan 15 00:00:00 EST 1994 · Journal of Applied Physics; (United States)

DOI:https://doi.org/10.1063/1.356509· OSTI ID:5446777

Aselage, T L; Venturini, E L; Van Deusen, S B ^[1]

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1. Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)

Phase equilibria in the Tl-Ca-Ba-Cu-O system have been studied at sample temperatures that are near, but below, the onset of melting. Independent control of the partial pressures of oxygen [ital P](O[sub 2]) and thallous oxide [ital P](Tl[sub 2]O) was achieved through the use of a two-zone furnace. Stable ranges of [ital P](Tl[sub 2]O), [ital P](O[sub 2]), and sample composition for individual Tl superconductors, including 2122, 2223, 1122, and 1223 (the latter intergrown with about 10% 2223) have been determined. A qualitative understanding of these stable ranges, based on the relative Tl content and formal oxidation state of the cations within a structure type, has been developed. From this information, equilibrium phase diagrams for Tl superconductors with Ca:Ba:Cu ratios of 1:2:2, 2:2:3, and 3:2:4 are proposed. These diagrams provide process information for the two-zone synthesis of bulk materials and thin and thick films. The superconducting transition temperatures of the individual phases produced by near-equilibrium processing are both reproducible and relatively insensitive to changes in the process conditions.

• DOE Contract Number: AC04-76DP00789
• OSTI ID: 5446777
• Journal Information: Journal of Applied Physics; (United States), Vol. 75:2; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM OXIDES
PHASE DIAGRAMS
CALCIUM OXIDES
COPPER OXIDES
THALLIUM OXIDES
EQUILIBRIUM
HIGH-TC SUPERCONDUCTORS
OXIDATION
TRANSITION TEMPERATURE
ZONE MELTING
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
CALCIUM COMPOUNDS
CHALCOGENIDES
CHEMICAL REACTIONS
COPPER COMPOUNDS
DIAGRAMS
MELTING
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
SUPERCONDUCTORS
THALLIUM COMPOUNDS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
360202* - Ceramics
Cermets
& Refractories- Structure & Phase Studies
360207 - Ceramics
Cermets
& Refractories- Superconducting Properties- (1992-)