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

Abstract

We prepared Dy_1−xSr_xCoO_3−δ (x=0,0.025) ceramics and evaluated their thermoelectric performances at temperatures up to 873 K. The sample in which x=0.025 showed a higher electrical conductivity and a lower Seebeck coefficient than that in which x=0. Due to phonon scattering, the thermal conductivity of the x=0.025 sample was lower than that of the x=0 sample over the entire range measured although the carrier component of thermal conductivity of the x=0.025 sample was slightly larger than that of the x=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=0.025 showed the highest figure of merit, Z=5.7×10⁻⁵ K⁻¹, at 773 K 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.