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 muV/K or more at a temperature of 300° C. or higher, and (iii) having an electric conductivity of 103 S/m or more at a temperature of 300° 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.