High temperature thermoelectric properties of Ca1-xDyxMnO2.98 (0≤x≤0.2)

High temperature thermoelectric properties of Cal-xDyxMnO2.98 (x = 0, 0.05, 0.10, 0.15, 0.20) have been measured in the temperature range from 300 to 1273 K. Ca1-xDyxMnO2.98 (x = 0.10, 0.15, 0.20) exhibited the metal-insulator transition in the relation between electrical resistivity and temperature, and the transition temperature increased with increasing x. Electrical resistivity in the metallic region decreased with increasing x content, reflecting the increase of Mn3+ ions, and the absolute value of Seebeck coefficient (alpha) also decreased. Thermal conductivity (lambda) did not considerably change with increasing x content. Among substituted CaMnO3, the highest figure of merit of Z = 1.05 X 10(-4) K-1 was obtained for x = 0.05 and 0.10 at 773 K, while a Z = 1.63 x 10(-4) K-1 was obtained for x = 0.20 at 1273 K.