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

Technical Report · Fri Jul 15 04:00:00 EDT 1988

OSTI ID:6885987

Li, S; Hayri, E A; Ramanujachary, K V; Greenblatt, M

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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36 MATERIALS SCIENCE
360202 -- Ceramics
Cermets
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ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
CHALCOGENIDES
CONVERGENCE
COPPER COMPOUNDS
CUPRATES
CURRENTS
DIRECT CURRENT
DOCUMENT TYPES
ELECTRIC CONDUCTIVITY
ELECTRIC CURRENTS
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ELEMENTS
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METALS
NEODYMIUM
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
POWDERS
PROGRESS REPORT
RARE EARTH COMPOUNDS
RARE EARTHS
SAMARIUM
SUPERCONDUCTIVITY
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS