Thermoelectric properties of Yb-La-Nb-doped SrTiO3

Yb2Ti2O7 exhibits ferromagnetic and magnetic properties, which are expected to exert a discernible influence on the thermoelectric properties of SrTiO3 composite. The La-Yb-Nb-doped SrTiO3 powders, synthesized via the hydrothermal method, were prepressed and then buried in carbon powder before being sintered in a muffle furnace at 1573 K for 5 h. The Yb dopant precipitated during the sintering process, leading to the in-situ for-mation of Yb2Ti2O7. The content of Yb2Ti2O7 increased with an increasing Yb concentration, resulting in a reduction in thermal conductivity and grain boundary potentials, and an increase in the peak electrical con-ductivity. The La and Nb dopants affect the electrical conductivity and the Seebeck coefficient. Therefore, by controlling the La, Nb, and Yb ratios, the La8Yb2Nb15 sample achieved the largest power factor (PF) value of 0.9 mWm- 1K-2 and a low thermal conductivity of 2.9 W m- 1K-1, resulting in a high ZT value of 0.32 at 1000 K.