Correlation of the superconducting transition to oxygen stoichiometry in single-crystal Ba[sub 1[minus][ital x]]K[sub [ital x]]BiO[sub 3[minus][ital y]]

Journal Article · Thu Jul 01 04:00:00 EDT 1993 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.48.611· OSTI ID:6489070

Mosley, W D; Dykes, J W; Klavins, P; Shelton, R N ^[1]; Sterne, P A; Howell, R H ^[2]

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1. Department of Physics, University of California-Davis, Davis, California 95616 (United States)
2. Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

Temperature-dependent positron-lifetime experiments have been performed from room temperature to 15 K on single crystals of the oxide superconductor Ba[sub 1[minus][ital x]]K[sub [ital x]]BiO[sub 3[minus][ital y]]. Results indicate that the filling of oxygen vacancies has a marked impact on the superconducting properties of this system. Cation defect concentrations were below the detectable limit of positron-annihilation-analysis techniques in this material, which is in sharp contrast to identical studies on polycrystalline samples. We find that the positron lifetime in these electrochemically deposited single crystals is determined by the oxygen stoichiometry of the lattice, but there is no experimental signature of strong positron localization. By performing a subsequent oxygen anneal on the crystals, the superconducting transition is sharpened and the onset is raised. The observed change in positron lifetime associated with this annealing procedure is in quantitative agreement with theory.

• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6489070
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 48:1; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360207* -- Ceramics
Cermets
& Refractories-- Superconducting Properties-- (1992-)
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
ANTILEPTONS
ANTIMATTER
ANTIPARTICLES
BARIUM COMPOUNDS
BARIUM OXIDES
BISMUTH COMPOUNDS
BISMUTH OXIDES
CHALCOGENIDES
CRYSTALS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTARY PARTICLES
ELEMENTS
FERMIONS
LEPTONS
LIFETIME
MATTER
MONOCRYSTALS
NONMETALS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
POSITRONS
POTASSIUM COMPOUNDS
POTASSIUM OXIDES
STOICHIOMETRY
SUPERCONDUCTIVITY
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE
TEMPERATURE RANGE 0013-0065 K
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K