Crystal chemistry of the La sub 2 minus y Ln sub y CuO sub 4 (Ln = Pr, Nd) systems

Journal Article · Tue Jul 31 20:00:00 EDT 1990 · Journal of Solid State Chemistry; (USA)

DOI:https://doi.org/10.1016/0022-4596(90)90042-V· OSTI ID:6387754

Manthiram, A; Goodenough, J B ^[1]

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1. Univ. of Texas, Austin (USA)

An investigation of the value of the room temperature crystallographic tolerance factor t at which stability of the La{sub 2}CuO{sub 4} T-tetragonal structure becomes unstable relative to the Nd{sub 2}CuO{sub 4} T{prime}-tetragonal structure in the systems La{sub 2{minus}y}Ln{sub y}CuO{sub 4}, Ln = Pr or Nd, has led to the discovery of a new T{double prime}-tetragonal phase. It has a powder X-ray diffraction pattern like that of the T{prime} phase, but with a slightly larger c parameter than that obtained by extrapolation from the T{prime} phase field. Its occurrence as nearly a line phase at y {approx} 0.5 suggests cation ordering within a Ln-O layer; with a larger size difference between La{sup 3+} and the Ln{sup 3+} ion, interlayer ordering occurs to give either a two-phase sample T/O + T{prime} or the hybrid T* phase.

• OSTI ID: 6387754
• Journal Information: Journal of Solid State Chemistry; (USA), Journal Name: Journal of Solid State Chemistry; (USA) Vol. 87:2; ISSN 0022-4596; ISSN JSSCB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CRYSTAL-PHASE TRANSFORMATIONS
DATA
ELEMENTS
EXPERIMENTAL DATA
HIGH-TC SUPERCONDUCTORS
INFORMATION
LANTHANUM
MEASURING INSTRUMENTS
MEASURING METHODS
METALS
NEODYMIUM
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PRASEODYMIUM
RARE EARTHS
SUPERCONDUCTORS
TETRAGONAL LATTICES
TRANSITION ELEMENT COMPOUNDS