Synthesis of Dy doped Yb0.1Ca0.9MnO3 ceramics with a high relative density and their thermoelectric properties

Perovskite-type Yb0.1Ca0.9−xDyxMnO3 ceramics were synthesized by solid state reaction. Their microstructures were characterized and the thermoelectric properties were evaluated between 300 K and 1100 K. Each of sample exhibits single phase with orthorhombic structure. All samples have high relative densities, and their values are between 95% and 97%, which is consistent with the SEM image. The electrical resistivity shows a typical metallic conductivity behavior. Lowest electrical resistivity 2.36 mΩ cm is achieved at room temperature, and the variation of electrical resistivity is not evident in whole measured temperature range. The Seebeck coefficients are negative, indicating an n-type conduction. The highest power factor 310 μW/(K2 m) is obtained for the sample with x = 0.02. The thermal conductivity is decreased by the difference in the mass between the Ca2+ and Dy3+ ions, especially in the heavy doped samples. The highest figure of merit is 0.11 at 1069 K for the sample with x = 0.02.