Effects of rare earth cations doped for La site on the oxide ionic conductivity of LaGaO₃-based perovskite type oxide

For the suppression of hole conduction in the high oxygen partial pressure range, effects of the addition of small amount of rare earth cations were investigated in this study with La_0.8Sr_0.2Ga_0.8Mg_0.2O_{3 - δ}. It was found that the addition of small amount of rare earth cations for La site in LaGaO₃ was effective for the suppression of hole conduction under high oxygen partial pressure, albeit the electrical conductivity decreased slightly. In particular, perovskite oxide of (La_0.9Nd_0.1)_0.8Sr_0.2Ga_0.8Mg_0.2O_{3 - δ} exhibits almost pure oxide ionic conduction over the oxygen partial pressure from 1 to 10^-21 atm, and the electrical conductivity attains the value of log (σ/S cm^-1) = -0.5 at 1223 K.