Charge transport in CaTiO3:: II.: Thermoelectric power

The present work describes the method of the measurement of thermoelectric power of oxide materials under the gas phase of controlled oxygen activity with high accuracy. The present study reports the thermopower data for undoped CaTiO3 at elevated temperatures (973-1323 K) and under the oxygen partial pressure in the range 10-10(5) Pa. The obtained experimental data indicate lack of consistency between the thermopower data determined in this work and the electrical conductivity data reported before with respect to the n-p transition point, that is, the p(O-2) corresponding to the minimum of electrical conductivity differs from that at which S = 0. The thermopower data were used to establish the temperature dependence of the electrical conductivity at constant thermopower. The obtained activation energy is in the range 119 kJ/mol in the n- and n-p transition regimes and assumes 146 kJ/mol in the p-type regime. (C) 2004 Kluwer Academic Publishers.