Orthorhombic-to-tetragonal transition in RA(1+x)Ba(2-x)Cu/sub 3/O(7+ delta) (Re=Nd, Sm, and Eu). Technical report No. 30, 1 July 1987-15 July 1988
The orthorhombic-to-tetragonal structural phase transition in the high-Tc superconducting oxides of the type R1+xBa2-xCu/sub 3/O(7-delta) (R (for rare earth) = Nd, Sm, and Eu) has been investigated using powder x-ray diffraction, dc resistivity, and thermogravimetric techniques. It was found that the orthorhombic-to-tetragonal transition occurs for samples whose nominal stoichiometric content of oxygen is greater than 7.0 (0 delta 0.3) as compared to less than 7.0 in YBa/sub 2/Cu/sub 3/O(7-delta). With increasing (R/Ba) ratio in R1+xBa2-xCu/sub 3/O delta, a clear convergence of multiple orthorhombic peaks to a well-defined single tetragonal peak was observed in the x-ray diffraction pattern. The presence or orthorhombic distortion in this system appears to be essential for achieving 90-K superconductivity.
- Research Organization:
- Rutgers--the State Univ., New Brunswick, NJ (USA). Dept. of Chemistry
- OSTI ID:
- 6885987
- Report Number(s):
- AD-A-197174/6/XAB
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360202 -- Ceramics
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360204* -- Ceramics
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ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
CHALCOGENIDES
CONVERGENCE
COPPER COMPOUNDS
CUPRATES
CURRENTS
DIRECT CURRENT
DOCUMENT TYPES
ELECTRIC CONDUCTIVITY
ELECTRIC CURRENTS
ELECTRICAL PROPERTIES
ELEMENTS
EUROPIUM
METALS
NEODYMIUM
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
POWDERS
PROGRESS REPORT
RARE EARTH COMPOUNDS
RARE EARTHS
SAMARIUM
SUPERCONDUCTIVITY
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS