Abstract
A perovskite structure contains local carriers, which conduct electricity by hopping. CaMnO3 displayed as a perovskite structure has superior thermal and oxidation resistance. An attempt was made to elevate thermoelectric performance by introducing impurities into the Mn site of CaMnO3.
The Seebeck coefficient α of the substituted CaMnO3 didn't exceed that of the standard for all temperature ranges. In all cases Seebeck coefficient showed roughly similar values. And in all cases, the Seebeck coefficient of the sample with a substituent of x=0.01 showed a high value, while that of the sample with a substituent of x=0.1 showed the greatest decrease.
Electrical resistivity ρ showed a constant value, as did Seebeck coefficient α. As the substitution percentage is increased, the electrical resistivity should decrease.
The thermal conductivity κ was measured on the samples only with a substituent of x=0.01. The standard sample showed about 1 (Wm−1K−1) over any temperature field.
As for the figure of merit Z, Ta and Nb substituted samples showed higher values than standard around 400(K). Above 400(K), standard showed higher value. The value of standard reached 5.2×10−5(K−1) at 800(K).
