In-plane thermal conductivity and Lorenz number in YBa{sub 2}Cu{sub 3}O{sub 7{minus}y}

Journal Article · Mon Sep 01 04:00:00 EDT 1997 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.56.5654· OSTI ID:538590

Takenaka, K; Fukuzumi, Y; Mizuhashi, K; Uchida, S ^[1]; Asaoka, H; Takei, H ^[2]

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1. Department of Superconductivity, The University of Tokyo, Bunkyo-ku, Tokyo 113 (Japan)
2. Institute for Solid State Physics, The University of Tokyo, Minato-ku, Tokyo 106 (Japan)

We make a tentative proposal to extract the electronic contribution to the in-plane thermal conductivity {kappa}{sub el}(T) of YBa{sub 2}Cu{sub 3}O{sub 7{minus}y} in the normal state. We have measured {kappa}{sub ab}(T) for single crystals with various oxygen contents (6.06{le} 7{minus}y {le}6.93). The systematic study of the oxygen-content dependence of {kappa}{sub ab} for the insulating phase enables us to estimate the phononic contribution {kappa}{sub ph}(T) for the metallic phase to some extent. Based on the estimated {kappa}{sub ph}, we examined {kappa}{sub el} from the view point of whether the Wiedemann-Franz law holds or not. The estimated {kappa}{sub el} appears to show only a weak T dependence and no significant change at a characteristic temperature T{sup {asterisk}} below which the electrical conductivity {sigma}{sub ab}(T) is enhanced possibly due to the opening of a spin gap. The difference between {kappa}{sub el} and {sigma}{sub ab} suggests the violation of the Wiedemann-Franz law below T{sup {asterisk}}. We discussed the ambiguity of our analyses and other possible interpretations of the present result as well as the picture of the charge transport speculated from the above suggestion. {copyright} {ital 1997} {ital The American Physical Society}

• OSTI ID: 538590
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 9 Vol. 56; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM OXIDES
COPPER OXIDES
ELECTRIC CONDUCTIVITY
HIGH-TC SUPERCONDUCTORS
PHONONS
STOICHIOMETRY
THERMAL CONDUCTIVITY
WIEDEMANN-FRANZ LAW
YTTRIUM OXIDES