Thermoelectric properties of perovskite oxides La1−xSrxCoO3 prepared by polymerlized complex method
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P-type perovskite oxides La1−xSrxCoO3 (0 ≤ x ≤ 0.2) have been prepared using a polymerlized complex method and sintering. The Seebeck coefficient, electrical conductivity, and thermal conductivity of the oxides were studied from room temperature to 773 K. The ln(σT)−1/T relationships revealed small-polaron hopping mechanism for the higher Sr contents. Large Seebeck coefficients were observed in lightly Sr-doped samples. Sr doping greatly reduced the Seebeck coefficient and enhanced the electrical and thermal conductivity of the samples. The temperature-induced spin-state transition of Co3+ ions strongly influenced the transport properties. The highest ZT value found in this series of oxides was 0.046 at 300 K for x = 0.1.
KeywordsThermoelectric Property Seebeck Coefficient LaCoO3 Measured Temperature Range Small Polaron Conduction
The authors would like to thank Dr. E. Müller, Dr. C. Stiewe, and W. Schönau from Institute of Materials Research, German Aerospace Center (DLR), for the measurements of thermal properties. TJZ would like to thank Dr. Jian He from Department of Physics and Astronomy, Clemson University, USA, for the discussion and comments. This work was supported by the National Science Foundation of China (50471039, 50522203) and PFDP of the Education Ministry of China (20060335126).