Abstract. The electrical conductivity of the SrTil.xFexO3-8, BaTil_xFexO3.8 and SrTil_xMnxO3_8 systems has been studied in a range of oxygen partial pressures between 10 -16 and 0.21 atm at 900 and 1000 ~ The materials exhibit predominantly ionic conductivity in a wide range of intermediate oxygen partial pressures. It has been found that in Fe doped strontium and barium titanates, the dependencies of the ionic conductivity on the acceptor concentration show a local maximum near x = 0.2. Taking into account that in the CaTil.xFexO3.ssystem (x = 0-0.5), the concentration dependence of the ionic conductivity also has a maximum near x = 0.2, it caq be concluded that this is a common phenomenon for Fe doped alkali earth titanates. An assumption has been made that a scheme of defect formation devised earlier for Fe doped calcium titanate is applicable for other alkali earth titanates.

Abstract.The electrical conductivity of perovskite-related oxides CaTil_xAlxO3~ and SrTil_xAlxO3_ 6 (x = 0 -0.4) were investigated within the temperature range 900 to 1000 ~ and the oxygen partial pressure range between 10 -20 and 0.21 atm using adc four-point technique. The materials investigated show predominantly p-type electronic conductivity at high, n-type electronic conductivity at low, and ionic conductivity at intermediate oxygen partial pressures. The values of ionic conductivity in CaTil_xAlxO3~ were found to be lower than those in CaTil_xFexO3_ ~. The effect of aluminium concentration on the high-temperature transport properties was examined.