It was noted that (Ba1-xLax)2In2O5 was an O-deficient perovskite oxide which exhibited a high oxide-ion conductivity. The conductivity was measured here as a function of the temperature and La content. It was found that, with increasing La content, a discontinuous jump in ion conduction in the Arrhenius plot (which was related to disordering of the O vacancies) disappeared from samples with x = 0.2. At x-values above 0.12, the ion conductivity increased linearly with La content while the activation energy remained constant with respect to the La content. The conductivity of samples with x = 0.6 was equal to 0.042S/cm at 1073K. This exceeded that of 8mol%Y2O3-stabilized ZrO2. The higher oxide-ion conductivity of this system was attributed to the numbers of mobile O ions.

Oxide-Ion Conductivity of (Ba1-xLax)2In2O5 System based on Brownmillerite Structure. K.Kakinuma, H.Yamamura, H.Haneda, T.Atake: Solid State Ionics, 2001, 140[3-4], 301-6