著者

Miyazaki Yuzuru Kudo Kazutaka Akoshima Megumi ONO Yasuhiro KOIKE Yoji KAJITANI Tsuyoshi

出版者

社団法人応用物理学会

雑誌

Japanese journal of applied physics. Pt. 2, Letters (ISSN:00214922)

巻号頁・発行日

vol.39, no.6, pp.L531-L533, 2000-06-01

被引用文献数

27 248

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Electric resistivity, thermoelectric power and thermal conductivity of a polycrystalline sample of the composite crystal[Ca_2CoO_<3.34>]_<0.614>[CoO_2], also known as Ca_3Co_4O_9, have been measured below 300K. Metallic conductivity accompanied by large thermoelectric power has been observed down to 50K. At 300K, the sample exhibits a thermoelectric power of S = 133μV・K^<-1> resistivity of ρ = 15mΩ・cm and thermal conductivity of κ = 9.8mW・K^<-1>・cm^<-1>. The resulting dimensionless figure of merit becomes ZT_<300>=3.5×10^<-2> which is comparable to the value reported for a polycrystalline sample of NaCo_2O_4, indicating that the title compound is a potential candidate for a thermoelectric material.