Effects of Strontium Ion Doping on the Thermoelectric Properties of Dysprosium Cobalt Oxide

We prepared Dy1 xSrxCoO3 (x 1⁄4 0; 0:025) ceramics and evaluated their thermoelectric performances at temperatures up to 873K. The sample in which x 1⁄4 0:025 showed a higher electrical conductivity and a lower Seebeck coefficient than that in which x 1⁄4 0. Due to phonon scattering, the thermal conductivity of the x 1⁄4 0:025 sample was lower than that of the x 1⁄4 0 sample over the entire range measured although the carrier component of thermal conductivity of the x 1⁄4 0:025 sample was slightly larger than that of the x 1⁄4 0 sample. Due to the effects of an increase of the electrical conductivity and a decrease of the thermal conductivity, the sample in which x 1⁄4 0:025 showed the highest figure of merit, Z 1⁄4 5:7 10 5 K , at 773K in the present system. These results imply that the partial substitution of a larger and lighter divalent cation for the trivalent cation of the A-site effectively enhanced the thermoelectric performance of the RCoO3 system. [doi:10.2320/matertrans.M2009335]