Charge transport in CaTiO3:: I.: Electrical conductivity

The present paper reports the electrical conductivity of polycrystalline undoped CaTiO3 in the temperature range 973-1323 K under controlled oxygen partial pressure (10-10(5) Pa). The electrical conductivity data are considered in terms of defect disorder and related semiconducting properties of CaTiO3. The values of the p(O-2) exponent of electrical conductivity at high p(O-2), that vary between 1/4.3 and 1/6.2 at 973 and 1323 K, respectively, are considered in terms of theoretical defect disorder model of p-type CaTiO3 and increasing effect of minority charge carriers (electrons) with temperature on p-type conduction. The activation energy of the electrical conductivity, assuming 125.3 kJ/mol at 10 Pa and 94.4 kJ/mol at 72 kPa, has been considered in terms of the formation of defect and their mobility. The band gap, determined from the minimum of electrical conductivity corresponding to the n-p transition is equal to 2.77 eV. (C) 2004 Kluwer Academic Publishers.