Structural properties and phase diagram of La[sub 2]Mo[sub 4+[delta]] (M = Ni, Cu)
- Univ. of Tokyo (Japan)
- Mie Univ. (Japan)
The phase diagram of La[sub 2]MO[sub 4+[delta]] (M = Ni, Cu) and the temperature dependence of orthorhombicity for several orthorhombic phases were investigated by in situ X-ray powder diffraction. A successive phase transition, tetragonal I4/mmm-[second-order] [yields] orthorhombic Bmab-[first-order] [yields] orthorhombicc Pccn, was observed in La[sub 2]NiO[sub 4.00]. The orthorhombicity of the Pccn phase decreases on cooling in contrast to that of the Bmab phase. The orthorhombic La[sub 2]NiO[sub 4.15] (Fmmm) shows a weak temperature dependence of orthorhombicity and exhibits a first-order phase transition to the tetragonal I4/mmm phase on heating. As judged from the temperature dependence of orthorhombicity, superconducting La[sub 2]CuO[sub 4.07], which results from the phase separation in the high-pressure oxygenated sample, is Bmab, while La[sub 2]CuO[sub 4.07] prepared by electrochemical oxidation at room temperature is Fmmm. 8 refs., 2 figs.
- OSTI ID:
- 7070538
- Report Number(s):
- CONF-930710--
- Journal Information:
- Journal of Superconductivity; (United States), Journal Name: Journal of Superconductivity; (United States) Vol. 7:1; ISSN JOUSEH; ISSN 0896-1107
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360607* -- Other Materials-- Superconducting Properties-- (1992-)
665411 -- Basic Superconductivity Studies-- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANNEALING
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISTRY
COHERENT SCATTERING
COPPER COMPOUNDS
COPPER OXIDES
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CRYSTAL-PHASE TRANSFORMATIONS
CUPRATES
DIAGRAMS
DIFFRACTION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTROCHEMISTRY
HEAT TREATMENTS
HIGH PRESSURE
HIGH-TC SUPERCONDUCTORS
LANTHANUM COMPOUNDS
NICKEL COMPOUNDS
ORTHORHOMBIC LATTICES
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PHASE DIAGRAMS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
PRESSURE DEPENDENCE
RARE EARTH COMPOUNDS
SCATTERING
SUPERCONDUCTIVITY
SUPERCONDUCTORS
SYNTHESIS
TEMPERATURE DEPENDENCE
TETRAGONAL LATTICES
TRANSITION ELEMENT COMPOUNDS
X-RAY DIFFRACTION