The Influence of Pb(Mg1/3Nb2/3)O3-doping on the thermoelectric properties of BaTiO3 ceramics

The low-lead (1-x)Pb(Mg1/3Nb2/3)O-3-xBaTiO(3) (x = 0, 0.025, 0.05, 0.075, 0.10 and 0.15) ceramics were fabricated by a two-step solid-state reaction route. The X-ray diffraction characterization confirms a perovskite crystal structure with tetragonal symmetry at room temperature (except for x = 0.15). SEM images indicate that all ceramic samples are dense and compact, with the grain size of 2-6 m. Along with the increase of Pb(Mg1/3Nb2/3)O-3 content, the electrical conductivity increases, and the Seebeck coefficient and the thermal conductivity decrease. With increasing temperature, sigma and alpha increase and kappa decreases. In general, adding Pb(Mg1/3Nb2/3)O-3 to BaTiO3 leads to an improvement of the thermoelectric figure of merit ZT. The results are explained on the basis of structural, morphological and compositional changes.