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Thermoelectric Properties of Bi 2.3-x Pb x Sr 2.6 Co 2 O y Single Crystals

2000; Institute of Physics; Volume: 39; Issue: 12R Linguagem: Inglês

10.1143/jjap.39.6658

1347-4065

Takayuki Itoh, Ichiro Terasaki,

Physics of Superconductivity and Magnetism

A set of single crystals of the layered cobaltite Bi 2.3- x Pb x Sr 2.6 Co 2 O y (0 ≤ x ≤0.44) were prepared by a flux technique. The resistivity ρ and the thermopower S along the in-plane direction were measured, and the thermoelectric properties were compared with those of other oxides. The Pb substitution causes a decrease in ρ and an increase in S below 100 K, which improves the power factor S 2 /ρ by 3–4 times. The transport parameters exhibit an anomaly near 25–50 K, such as a plateau in S and an upturn in ρ, which we ascribe to the reduction of the density of states owing to a pseudogap.