Thermoelectric Properties of CeFe₃CoSb₁₂-FeSb₂ Composite

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We have prepared a sintered CeFe₃CoSb₁₂-FeSb₂ composite and investigated the Seebeck coefficient, electrical resistivity, and thermal conductivity in order to estimate the corresponding figure of merit. The thermal conductivity of the composite whose molar ratio of CeFe₃CoSb₁₂ to FeSb₂ is 0.9:0.1 is as large as that of CeFe₃CoSb₁₂ while the lattice contribution of the thermal conductivity of the composite is somewhat smaller than that of CeFe₃CoSb₁₂, which is ascribed to the enhancement of the phonon scattering caused by the additive material. With increasing FeSb₂ content the thermal conductivity of the composite is enhanced. The Seebeck coefficient and electrical resistivity of the composite generally decrease with increasing FeSb₂ content. These behaviors in the thermal conductivity, Seebeck coefficient and electrical resistivity with increasing FeS₂ content is considered to be ascribed to the physical properties of FeSb₂. As a result, the composite whose molar ratio of CeFe₃CoSb₁₂ to FeSb₂ is 0.9:0.1 shows somewhat larger figure of merit than CeFe₃CoSb₁₂ in the whole temperature range from 373K to 773K.