Observation of lanthanum- and rare-earth-site ordering in T sup * -phase La sub 2 minus x minus y R x Sr sub y CuO sub 4 ( R =Sm, Eu, Gd, Tb) (USA)
- Physics Department, University of Connecticut, Storrs, CT (USA) Institute of Materials Science, University of Connecticut, Storrs, CT (USA)
- AT T Bell Laboratories, Murray Hill, NJ (USA)
There are two inequivalent lanthanum and/or rare-earth ({ital R}) sites in the {ital T}{sup *}-phase La{sub 2{minus}{ital x}{minus}{ital y}R{ital x}}Sr{sub {ital y}}CuO{sub 4} structure. One site {ital M} is locally similar to that in the {ital T} structure (K{sub 2}NiF{sub 4}-type) and the other site ({ital M}{prime}) is locally similar to that in the {ital T}{prime} structure (Nd{sub 2}CuO{sub 4}-type). By studying the x-ray-absorption near-edge structure and extended fine structure of both La and rare-earth elements in {ital T}-, {ital T}{prime}-, and {ital T}{sup *}-phase materials, we find unambiguously that the La and {ital R} ions enter the two inequivalent sites in an ordered way in the {ital T}{sup *}-phase La{sub 0.9}{ital R}{sub 0.9}Sr{sub 0.2}CuO{sub 4} ({ital R} is one of Sm, Eu, Gd, or Tb). The La and the rare-earth ions preferentially occupy the {ital M} and {ital M}{prime} sites, respectively.
- OSTI ID:
- 6484468
- Journal Information:
- Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 42:7; ISSN 0163-1829; ISSN PRBMD
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
ABSORPTION SPECTRA
ALKALINE EARTH METAL COMPOUNDS
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CRYSTAL STRUCTURE
EUROPIUM COMPOUNDS
EUROPIUM OXIDES
GADOLINIUM COMPOUNDS
GADOLINIUM OXIDES
HIGH-TC SUPERCONDUCTORS
LANTHANUM COMPOUNDS
LANTHANUM OXIDES
OXIDES
OXYGEN COMPOUNDS
RARE EARTH COMPOUNDS
SAMARIUM COMPOUNDS
SAMARIUM OXIDES
SPECTRA
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
SUPERCONDUCTORS
TERBIUM COMPOUNDS
TERBIUM OXIDES
TRANSITION ELEMENT COMPOUNDS
X-RAY SPECTRA