Electronic carrier mobilities of BaTiO3

Electronic carrier mobilities of a mixed conductor oxide are one of the most difficult parameters to characterize. A most direct way may be to measure the Hall effect in combination with electronic conductivity, but measurement of the Hall effect in situ at elevated temperatures is never trivial. Thermopower is often employed in association with the conductivity, but the lack of knowledge of the effective densities-of-states and heats-of-transport of the carriers often renders the result unreliable, too. The mobilities of electronic carriers of BaTiO3 thus remain not so well known except for a few estimates of them. Recently, we have evaluated the mobilities of electrons (μn) and holes (μp) over the temperature range 800–1100 °C by measuring electrical conductivity and chemical diffusivity on undoped and 1.8 m/o Al-doped BaTiO3, respectively, in their mixed n/p regimes. It has been found that for the undoped, μn=0.13 and μp=0.08 cm2/V-s and for the Al-doped, μn=0.08 and μp=1.99103exp(−1.14eV/kT) cm2/V-s over the temperature range examined.