High temperature thermoelectric performance of Ca1−xDyxMn1−xNbxO3 ceramics (x≤0·10)

Abstract

Perovskite type Ca1−xDyxMn1−xNbxO3 ceramics (x≤0·10) are synthesised by solid state reaction. Microstructures are characterised, and the thermoelectric properties are evaluated between 300 and 1100 K. The samples obtained in this work have high relative densities. The electrical resistivity shows a typical metallic conductivity behaviour and decreases with substitution, the variation of which is not significant in whole measured temperature range. The Seebeck coefficients are negative, indicating n type conduction, and the largest value is obtained, −174 μV K−1, at x = 0·02. The highest power factor is 258 μW (K2 m)−1 for the x = 0·02 sample. A maximum ZT value reaches 0·08 for electron doped Ca0·98Dy0·02Mn0·98Nb0·02O3 at 973 K, which is about twice as high as that of undoped CaMnO3.