Oxygen isotope study of YBa/sub 2/Cu/sub 3/O/sub 7/

Journal Article · Wed Feb 01 04:00:00 EST 1989 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.39.2269· OSTI ID:6481666

Hoen, S; Creager, W N; Bourne, L C; Crommie, M F; Barbee, III, T W; Cohen, M L; Zettl, A; Bernardez, L; Kinney, J

The magnitude of the oxygen isotope effect in the high-T/sub c/ superconductor YBa/sub 2/Cu/sub 3/O/sub 7/ has been determined by substitution of /sup 18/O for /sup 16/O. A series of cross exchanges was performed on high-quality polycrystalline specimens to eliminate uncertainties due to sample heat treatments and sample inhomogeneities. Magnetic measurements suggest a relative isotope shift for the bulk material of -0.17 +- 0.03 K at 80 at. % /sup 18/O substitution, yielding ..cap alpha../sub bulk/ = 0.019 +- 0.004 where T/sub c/approx.M/sup -//sup ..cap alpha../ and M is the oxygen mass. Resistivity measurements in freshly prepared specimens reveal filamentary superconductivity 1 or 2 K above the bulk superconducting transition temperature. The isotope shift associated with the filamentary superconductivity is similar to but slightly larger than the bulk shift: ..cap alpha../sub fil/ = 0.028 +- 0.003. The filamentary superconductivity is time dependent and disappears several months after sample preparation. We show that the above values of ..cap alpha.. are inconsistent with the standard three-dimensional phonon-mediated Bardeen-Cooper-Schrieffer theory, and discuss implications for alternative possibilities.

• Research Organization: Department of Physics, University of California at Berkeley, and Materials and Chemical Sciences Division, Lawrence Berkeley Laboratory, Berkeley, California 94720
• OSTI ID: 6481666
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 39:4; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
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
BCS THEORY
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CRYSTALS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
EVEN-EVEN NUCLEI
ISOTOPE EFFECTS
ISOTOPES
LIGHT NUCLEI
NUCLEI
OXIDES
OXYGEN 18
OXYGEN COMPOUNDS
OXYGEN ISOTOPES
PHONONS
PHYSICAL PROPERTIES
POLYCRYSTALS
QUASI PARTICLES
STABLE ISOTOPES
SUPERCONDUCTORS
THERMODYNAMIC PROPERTIES
TIME DEPENDENCE
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
YTTRIUM COMPOUNDS
YTTRIUM OXIDES