Evidence for bulk oxygen in La sub 2 CuO sub 4+. delta. : Specific-heat studies
- Department of Physics, University of Florida, Gainesville, FL (USA)
- Sandia National Laboratories, Albuquerque, NM (USA)
Specific-heat measurements of a powder sample of La{sub 2}CuO{sub 4+{delta}} with {delta}{similar to}0.13 indicate the presence of bulk oxygen, as determined by transitions at 24, 43.7, and 54.5 K as found in solid O{sub 2}. A large difference in the cubic specific-heat temperature coefficients of a high-pressure-oxygenated superconducting sample and an ambient-pressure-oxygenated nonsuperconducting sample of La{sub 2}CuO{sub 4+{delta}} can be attributed to the unbound oxygen. Electronic specific-heat coefficients {gamma} of the two samples are 2.4{plus minus}0.3 and 0{plus minus}0.3 mJ/K{sup 2} mol, respectively. Effects of bulk oxygen on measured thermodynamic properties of high-temperature superconductors are discussed.
- DOE Contract Number:
- FG05-86ER45268; AC04-76DP00789
- OSTI ID:
- 5963285
- Journal Information:
- Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 42:16; ISSN 0163-1829; ISSN PRBMD
- Country of Publication:
- United States
- Language:
- English
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360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRONIC SPECIFIC HEAT
ELEMENTS
HIGH-TC SUPERCONDUCTORS
LANTHANUM COMPOUNDS
LANTHANUM OXIDES
NONMETALS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
PRESSURE DEPENDENCE
RARE EARTH COMPOUNDS
SPECIFIC HEAT
STOICHIOMETRY
SUPERCONDUCTIVITY
SUPERCONDUCTORS
TEMPERATURE DEPENDENCE
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
ULTRALOW TEMPERATURE
VERY LOW TEMPERATURE