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Negative thermopower of YbBa sub 2 Cu sub 3 O sub 7 minus y

Journal Article · · Physical Review, B: Condensed Matter; (USA)
;  [1]
  1. Department of Physics, Sungkyunkwan University, Suwon (Korea)

We have measured the thermopower of {ital R}Ba{sub 2}Cu{sub 3}O{sub 7{minus}{ital y}} for {ital R}=Yb, Er, Y, Dy, and Gd as a function of temperature with further details on the Yb compound. We find that the Yb compound has a negative thermopower at all temperatures above {Tc} unlike the other compounds, whereas its temperature dependence is similar to that of the others. We also find that as the oxygen deficiency increases, the thermopower of YbBa{sub 2}Cu{sub 3}O{sub 7{minus}{ital y}} increases and becomes positive, while the whole shape of the thermopower-versus-temperature curve remains nearly unchanged. The observed insensitivity of the thermopower-versus-temperature profile to the sign of the thermopower or to the carrier concentration indicates that the electronic structure of the 1:2:3 compounds cannot be adequately explained within a single-conduction-band framework.

OSTI ID:
6436868
Journal Information:
Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 42:4; ISSN PRBMD; ISSN 0163-1829
Country of Publication:
United States
Language:
English