Doping effect of Sr²⁺ on electrical conductivity in la _1-xSr_xSc_1-yAl_yO₃ perovskite-type oxides

The total electrical conductivities of Sr²⁺ and Al ³⁺-doped LaScO₃ materials, La_1-xSr _xSc_1-yAl_yO₃ (x = 0.1-0.325, y = 00.01), were examined under wet, dry, reduced and oxidized conditions and were found to express mixed ionic and electronic conductivities. In the high temperature range of 1073 to 1273 K, oxide-ion conduction was predominant. In the systematic measurement of electrical conductivity, we found that the oxide-ion conductivities and activation energies show continuous changes over a wide range of Sr²⁺ dopant concentrations. We also found that oxide-ion conduction was enhanced by Sr²⁺ doping to the La ³⁺ site. The ionic transference number, t_ion, calculated from the conductivity data under high and low P(O₂) conditions was 0.73 (x = 0.325, y = 0.01) at 1273 K.