Superconductivity at 67 K in (Pb,Cu)Sr sub 2 (Ca,Y)Cu sub 2 O sub 7 by precise adjustment of oxygen

Journal Article · Mon Apr 01 04:00:00 EST 1991 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.43.7936· OSTI ID:5692315

Tang, X X; Morris, D E; Sinha, A P.B. ^[1]

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1. Morris Research Inc., 1918 University Avenue, Berkeley, California 94704 (US)

We demonstrate that high-temperature superconductivity (HTSC) with {ital T}{sub {ital c}}=67 K can be induced in (Pb,Cu)Sr{sub 2}(Y,Ca)Cu{sub 2}O{sub 7{minus}{delta}} by precise oxygen adjustment, which is accomplished by heat treatment in high {ital P}(O{sub 2}), followed by quenching. Superconductivity with {ital T}{sub {ital c}}{approx}17 K was previously reported in this compound obtained by quenching from high temperature in 1 atm of oxygen. Since quenching leaves less oxygen than in annealed samples, it appears paradoxical that HTSC can be induced in this compound by high-pressure oxygen treatment. We find that, while oxidation in high {ital P}(O{sub 2}) produces HTSC, excess oxygen taken up during subsequent annealing at lower temperature destroys the superconductivity; so quenching is required for high {ital T}{sub {ital c}}. Thermogravimetric analysis shows that weakly bound oxygen is taken up into several distinct sites, one of which is required for the appearance of HTSC. However, occupation of the most weakly bound sites is detrimental to HTSC, at least in (Pb,Cu)Sr{sub 2}(Y,Ca)Cu{sub 2}O{sub 7}. The appearance and then destruction of high-temperature superconductivity by adding successive amounts of oxygen in different sites may be a powerful tool to explore the mechanism of high-temperature superconductivity.

• OSTI ID: 5692315
• Journal Information: Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 43:10; ISSN PRBMD; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALINE EARTH METAL COMPOUNDS
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
CHEMICAL ANALYSIS
CHEMICAL REACTIONS
COHERENT SCATTERING
COPPER COMPOUNDS
COPPER OXIDES
CRYSTAL STRUCTURE
DIFFRACTION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRONIC EQUIPMENT
EQUIPMENT
FLUXMETERS
GRAVIMETRIC ANALYSIS
HIGH-TC SUPERCONDUCTORS
LEAD COMPOUNDS
LEAD OXIDES
MAGNETIC PROPERTIES
MEASURING INSTRUMENTS
MICROWAVE EQUIPMENT
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
QUANTITATIVE CHEMICAL ANALYSIS
SCATTERING
SQUID DEVICES
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
SUPERCONDUCTING DEVICES
SUPERCONDUCTIVITY
SUPERCONDUCTORS
THERMAL ANALYSIS
THERMAL GRAVIMETRIC ANALYSIS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
X-RAY DIFFRACTION
YTTRIUM COMPOUNDS
YTTRIUM OXIDES