Synthesis and characterization of fluoride-substituted RBa/sub 2/Cu/sub 3/O/sub 7/: R = Y, Eu, La

Journal Article · Sun Jan 01 04:00:00 EST 1989 · Materials Research Bulletin; (USA)

DOI:https://doi.org/10.1016/0025-5408(89)90017-2· OSTI ID:5372326

Vanderah, T A; Decker, D L; Harris, D C ^[1]; Chamberland, B L ^[2]

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1. Naval Weapons Center, China Lake, CA (USA). Research Dept.
2. Connecticut Univ., Storrs, CT (USA). Dept. of Chemistry

Oxyflouride derivatives of the parent YBa/sub 2/Cu/sub 3/O/sub 7/ compound with target formulas RBa/sub 2/Cu/sub 3/O/sub 6/F, R = Y, Eu, or La, were synthesized by solid state reaction of ROF, BaCO/sub 3/, and CuO. Formation of BaF/sub 2/ was always observed, and this phase could not be avoided by varying reactants, time, or temperature. RBa/sub 2/Cu/sub 3/O/sub 6/F analogs containing the minimum amounts of BaF/sub 2/ were characterized by semi-quantitative X-ray diffraction analysis, iodometric titration, fluoride ion analysis, and magnetization measurements. The results are consistent with the incorporation of 0.2-0.3 mole fluoride per mole of compound, resulting in approximate stoichiometries RBa/sub 2/Cu/sub 3/O/sub x/F/sub 0.2-0.3/. Substitution of fluoride for oxide in this system degrades rather than enhances the high-temperature superconductivity. For the yttrium and europium systems, the superconducting transitions were broadened and the onset temperatures were lowered by 20-25 {Kappa}; the lanthanum oxyfluoride analog was not superconducting.

• OSTI ID: 5372326
• Journal Information: Materials Research Bulletin; (USA), Journal Name: Materials Research Bulletin; (USA) Vol. 24:1; ISSN MRBUA; ISSN 0025-5408
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202 -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
CHEMICAL COMPOSITION
CHEMICAL REACTION KINETICS
COHERENT SCATTERING
COPPER COMPOUNDS
COPPER OXIDES
DIFFRACTION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
EUROPIUM COMPOUNDS
EUROPIUM OXIDES
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
HIGH TEMPERATURE
KINETICS
LANTHANUM COMPOUNDS
LANTHANUM OXIDES
MAGNETIZATION
OXIDES
OXYGEN COMPOUNDS
PHASE STUDIES
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
REACTION KINETICS
SCATTERING
SUPERCONDUCTIVITY
SUPERCONDUCTORS
SYNTHESIS
TRANSITION ELEMENT COMPOUNDS
X-RAY DIFFRACTION
YTTRIUM COMPOUNDS
YTTRIUM OXIDES