Complex oxide having high seebeck coefficient and high electric conductivity

摘要

This invention provides a complex oxide comprising the features of:(i) being represented by the formula : Ca3-xRExCo4Oy wherein RE is a rare earth element, 0 </= x </= 0.5 and 8.5 </= y </= 10, (ii) having a Seebeck coefficient of 100 mu V/K or more at a temperature of 300 DEG C or higher, and (iii) having an electric conductivity of 10<3> S/m or more at a temperature of 300 DEG C or higher. The complex oxide is composed of low-toxicity elements, excellent in heat resistance and chemical durability and high in thermoelectric conversion efficiency.