Thermal conductivity in the ab plane of untwinned YBa sub 2 Cu sub 3 O sub 7 minus. delta

Journal Article · Mon Jun 01 04:00:00 EDT 1992 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.45.13144· OSTI ID:7293708

Cohn, J L; Skelton, E F; Wolf, S A ^[1]; Liu, J Z; Shelton, R N ^[2]

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1. Materials Physics Branch, Naval Research Laboratory, Washington, D.C. 20375 (United States)
2. Department of Physics, University of California at Davis, Davis, California 95616 (United States)

We present measurements of thermal conductivity ({kappa}) in the {ital ab} plane of untwinned YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} ({delta}{approx}0.10) for {ital T}{le}200 K. {kappa} has been measured with heat flow along both the {ital a} and {ital b} axes and for two oxygen configurations of the same crystal. The conductivity anisotropy has its maximum value at the conductivity peak ({ital T}{approx}40 K), where we find {kappa}{sub {ital a}}/{kappa}{sub {ital b}}{approx}1.15 before and after an oxygen anneal. Very little {ital ab} anisotropy in the magnitude of {kappa} is observed in the normal state, though near {ital T}{sub {ital c}} the temperature dependences are noticeably different for the two directions: {ital d}{kappa}/{ital dT}{gt}0 along the {ital b} axis and {ital d}{kappa}/{ital dT}{lt}0 along the {ital a} axis. Near {ital T}{sub {ital c}} ({ital T}{le}110 K) {kappa} is enhanced slightly for both transport directions, features we attribute to the effect of superconducting fluctuations.

• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 7293708
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 45:22; 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
ANISOTROPY
ANNEALING
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
FLUCTUATIONS
HEAT TREATMENTS
HIGH-TC SUPERCONDUCTORS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SUPERCONDUCTORS
TEMPERATURE EFFECTS
THERMAL CONDUCTIVITY
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
VARIATIONS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES