R sub 2 Ba sub 4 Cu sub 7 O sub 15 minus. delta. : A 92-K bulk superconductor

Journal Article · Sun Apr 01 00:00:00 EST 1990 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.41.7220· OSTI ID:6904973

Tallon, J L; Pooke, D M; Buckley, R G; Presland, M R ^[1]; Blunt, F J ^[2]

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1. Physics and Engineering Laboratory, Department of Scientific and Industrial Research, P.O. Box 31313, Lower Hutt, New Zealand (NZ)
2. Interdisciplinary Research Center in Superconductivity, Cambridge University, Madingley Road, CB30HE, United Kingdom (GB)

Superconductivity is investigated in {ital R}{sub 2}Ba{sub 4}Cu{sub 7}O{sub 15{minus}{delta}} ({ital R}=Y or Er) as a function of oxygen stoichiometry. High-quality single-phase ceramic samples prepared at 869 {degree}C in oxygen at one atmosphere were annealed under various oxygen partial pressures and temperatures then rapidly quenched into liquid nitrogen to fix the value of {delta}. {ital T}{sub {ital c}} was found to decrease monotonically with {delta} from a maximum of 92 K when {delta}=0, to a minimum of 30 K when {delta}=10. The normal-state carrier concentration has a one-to-one correspondence with {delta}. There is no significant difference between the oxygen unloading curves for {delta} as a function of temperature and pressure for Y{sub 2}Ba{sub 4}Cu{sub 7}O{sub 15{minus}{delta}} and YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}; i.e., the unloading in the latter is twice that of the former. The volume change per oxygen vacancy is 3.1 A per formula unit compared to 3.6 A for YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}. The material remains orthorhombic for all values of {delta}.

• OSTI ID: 6904973
• Journal Information: Physical Review, B: Condensed Matter; (USA), Vol. 41:10; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM OXIDES
SUPERCONDUCTIVITY
COPPER OXIDES
ERBIUM OXIDES
TRANSITION TEMPERATURE
YTTERBIUM OXIDES
CORRELATIONS
OXYGEN
SAMPLE PREPARATION
STOICHIOMETRY
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
CHALCOGENIDES
COPPER COMPOUNDS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
ERBIUM COMPOUNDS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
YTTERBIUM COMPOUNDS
360204* - Ceramics
Cermets
& Refractories- Physical Properties