EFFECTS OF SINTERING TEMPERATURE ON THERMOELECTRIC PROPERTIES OF NANOCRYSTALLINE Ca_(0.9)Yb_(0.1)MnO_3 PREPARED BY CO-PRECIPITATION METHOD

摘要

This paper reports high temperature thermoelectric properties of ytterbium doped calcium manganite, Ca_(0.9)Yb_(0.1)MnO_3, synthesized using co-precipitation method followed by sintering in air at different temperatures ranging from 1223 to 1373 K. The grain sizes increases with increasing the sintering temperature. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to study microstructures of the sintered samples. The effects of sintering temperature on thermoelectric properties can be explained by considering grain size and density of the samples. A maximum dimensionless figure of merit ZT of 0.18 was obtained at 973 K for the sample with 95% relative density.