This paper reports about Seebeck measurements of the perovskite phase NaTaO3. To increase the carrier concentration, specimens including metallic transition metals such as Mn, Cr, Fe, Ti were sintered at 1273 K and 1473 K. Mircostructural characterization by SEM and XRD showed that besides the perovskite phase, transition metal oxides are present. The solubility limit of NaTaO3 increases with the sintering temperature and is about 17% in the case of Fe after sintering at 1473 K for 10 h. For NaTaO3 with 50 mol% Fe2O3 at a temperature difference of 800 K a Seebeck voltage of -320 mV was measured. This is the highest Seebeck voltage among all the specimens and leads to a Seebeck coefficient of -0.45 mV/K. The specific electric resistivity decreases with an increase in the temperature from 50 M Omega m at room temperature to 5 Omega m at 1273 K. The power factor of this new n-type thermoelectric candidate material is estimated.

Keywords: n-type thermoelectric materials; Seebeck coefficient; perovskite; microstructure