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

Journal Article · Sat Jan 15 04:00:00 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), Journal Name: Journal of Applied Physics; (United States) Vol. 75:2; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

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