Monte Carlo study of oxygen-vacancy ordering in YBa sub 2 Cu sub 3 minus x M sub x O sub 6+2 c ( M =Co,Fe,Al,Ga)

Journal Article · Sat Dec 01 04:00:00 EST 1990 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.42.10152· OSTI ID:5942375

Salomons, E; de Fontaine, D ^[1]

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1. Department of Materials Science and Mineral Engineering, University of California, Berkeley, CA (USA) Lawrence Berkeley Laboratory, Berkeley, CA (USA)

The effect of impurities at the Cu(1) site in the basal plane of the high-temperature superconductor YBa{sub 2}Cu{sub 3}O{sub 6+2{ital c}} on the oxygen-vacancy phase diagram is investigated by Monte Carlo simulation of an asymmetric next-nearest-neighbor lattice-gas model, in which the impurities are assumed to act as traps for oxygen atoms. First the phase diagram of YBa{sub 2}Cu{sub 3}O{sub 6+2{ital c}} is determined, which shows the high-temperature orthorhombic and tetragonal phases, as well as the low-temperature double-cell orthorhombic and antiorthorhombic phases. Next the high-temperature orthorhombic-to-tetragonal transition of YBa{sub 2}Cu{sub 3{minus}{ital x}}{ital M}{sub {ital x}}O{sub 6+2{ital c}} is studied within a single orthorhombic domain. This orthorhombic-to-tetragonal transition is a true phase transition, with a peak in the specific heat, in contrast with the orthorhombic-to-pseudotetragonal transition studied in previous theoretical studies. The orthorhombic-to-tetragonal phase boundary is found to shift to higher oxygen concentrations with increasing impurity concentration. A first-order approximation for the shift of the phase boundary is derived, which agrees with the Monte Carlo results.

• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5942375
• Journal Information: Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 42:16; ISSN 0163-1829; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
ALKALINE EARTH METAL COMPOUNDS
ALLOYS
ALUMINIUM ADDITIONS
ALUMINIUM ALLOYS
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COBALT ADDITIONS
COBALT ALLOYS
COPPER COMPOUNDS
COPPER OXIDES
CRYSTAL DEFECTS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CRYSTAL-PHASE TRANSFORMATIONS
GALLIUM ADDITIONS
GALLIUM ALLOYS
IRON ADDITIONS
IRON ALLOYS
MONTE CARLO METHOD
ORTHORHOMBIC LATTICES
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
POINT DEFECTS
SPECIFIC HEAT
TETRAGONAL LATTICES
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
VACANCIES
YTTRIUM COMPOUNDS
YTTRIUM OXIDES