Fabrication of (Ca1-xLax)MnO3 Ceramics with a High Relative Density and their Power Factor

Perovskite-type (Ca1-xLax)MnO3 powders were synthesized using a Pechini-type polymerized complex route, and (Ca1-x La-x)MnO3 ceramics with a high relative density (85.6%-98.5%) were fabricated using a planetary mill and cold-isostatic pressing (CIP) in order to improve the electrical and thermoelectric properties. The electrical conductivity (Sigma) was independent of both x and the temperature, and the relationship between log Sigma T vs. 1000/T was linear. The Seebeck coefficient (S) was negative, and the absolute value of the Seebeck coefficient increased with temperature and decreased with increases of x. The highest value of the power factor (S2 Sigma) was 3-4 x 10-4 W/(K2 center dot m) for the (Ca0.96La0.04)MnO3 ceramic.