In situ observation of the orthorhombic-tetragonal phase transformation in YBa sub 2 Cu sub 3 O sub 7 minus. delta

Journal Article · Fri Feb 15 04:00:00 EST 1991 · Journal of Applied Physics; (USA)

DOI:https://doi.org/10.1063/1.348674· OSTI ID:5845515

Monteiro, O R; Evans, J W ^[1]; Johnson, S M ^[2]

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1. Materials and Chemical Sciences Division, Lawrence Berkeley Laboratory, Berkeley, California 94720 (US)
2. SRI International, 333 Ravenswood Ave., Menlo Park, California 94025 (USA)

We have carried out {ital in} {ital situ} heat treatments of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} at temperatures between 25 and 500 {degree}C and oxygen pressure of 10 Torr. It was found that the original orthorhombic ({ital OI} phase) YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} transforms into the {ital OII} phase (still orthorhombic, but with a doubling of the {ital a}-axis, and with a {delta}=0.5) at about 250 {degree}C. As the temperature is increased further, the tetragonal phase of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} forms. As the tetragonal phase is slowly cooled to room temperature, the orthorhombic phase {ital OI} reappears. Cycling the temperature repeatedly has indicated the regenerability of the {ital OI} phase.

• OSTI ID: 5845515
• Journal Information: Journal of Applied Physics; (USA), Journal Name: Journal of Applied Physics; (USA) Vol. 69:4; ISSN 0021-8979; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CRYSTAL-PHASE TRANSFORMATIONS
ELECTRON MICROSCOPY
ELEMENTS
HEAT TREATMENTS
HIGH TEMPERATURE
HIGH-TC SUPERCONDUCTORS
LOW PRESSURE
MEDIUM TEMPERATURE
MICROSCOPY
NONMETALS
ORTHORHOMBIC LATTICES
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
SUPERCONDUCTORS
TETRAGONAL LATTICES
TRANSITION ELEMENT COMPOUNDS
TRANSMISSION ELECTRON MICROSCOPY
YTTRIUM COMPOUNDS
YTTRIUM OXIDES