High-temperature electrical transport in Al-doped calcium and strontium titanates

The electrical conductivity of perovskite-related oxides CaTi1-xAlxO3-delta and SrTi1-xAlxO3-delta (x = 0 - 0.4) were investigated within the temperature range 900 to 1000 degreesC and the oxygen partial pressure range between 10(-20) and 0.21 atm using a dc 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 CaTi1-xAlxO3-delta were found to be lower than those in CaTi1-xFexO3-delta. The effect of aluminium concentration on the high-temperature transport properties was examined.