Transmission-electron-microscopy study of the transition from tetragonal to orthorhombic YBa sub 2 (Cu sub 1 minus x Fe sub x ) sub 3 O sub 6+ y

Journal Article · Wed Apr 01 04:00:00 EST 1992 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.45.8042· OSTI ID:7306493

Romano, L T ^[1]; Smith, M G ^[2]; Oesterreicher, H ^[3]; Taylor, R D ^[4]

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1. Department of Materials, University of Oxford, Parks Road, OX13Ph (United Kingdom)
2. Center for Materials Science and Engineering, University of Texas at Austin, ETC 9.104, Austin, Texas 78712 (United States) Physics Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
3. Department of Chemistry, University of California, San Diego, La Jolla, California 92093-0317 (United States)
4. Physics Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

We report on the difference in microstructure of conventionally prepared YBa{sub 2}(Cu{sub 1{minus}{ital x}}Fe{sub {ital x}}){sub 3}O{sub 6+{ital y}} ({ital x}=0.06 and 0.10) compared to materials that have been cooled under N{sub 2} (reducing atmosphere preparation) and subsequently reoxygenated near 350 {degree}C. The microstructure of conventionally prepared tetragonal materials shows a complex structure (with small-scale orthogonal striations). Materials prepared under reducing conditions, however, are orthorhombic and show a microstructure that is a mixture of a twin structure and a structure with small-scale striations of order 100 A only along the (110) direction, of which about every sixth appears to be supporting a twin boundary. This can be related to Moessbauer evidence for the formation of extended Fe-O clusters. We propose that the ordered striations in the Cu(1) plane are regions of Fe enrichments. This dilutes Fe from the matrix and leaves {ital T}{sub {ital c}} relatively unaffected, compared with the parent compound.

• OSTI ID: 7306493
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 45:14; ISSN PRBMD; ISSN 0163-1829
• 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
HIGH-TC SUPERCONDUCTORS
IRON COMPOUNDS
IRON OXIDES
MICROSCOPY
MICROSTRUCTURE
ORTHORHOMBIC LATTICES
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
SUPERCONDUCTORS
TETRAGONAL LATTICES
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
TRANSMISSION ELECTRON MICROSCOPY
YTTRIUM COMPOUNDS
YTTRIUM OXIDES