The crystal structure and conductivity of (Ba1-xLax)2In2O5, where x ranged from 0 to 0.50, were studied. Rietveld results, for x-values of 0.20 or 0.40, revealed that these oxides belonged to the cubic Pm3m space group. This indicated that the oxide-ion vacancies were distributed randomly in the cubic perovskite-type structure. The conductivities, for x-values of 0.20, 0.40 and 0.50, did not exhibit a sharp discontinuity because the disordered phase of the defective perovskite-type structure was stabilized at low temperatures by doping with La3+ cations. The oxide-ion transference number, as determined by using the blocking method, was 1.00.

Crystal Structure of (Ba,La)2In2O5 and its Oxide Ion Conductivity. Y.Uchimoto, T.Yao, H.Takagi, T.Inagaki, H.Yoshida: Electrochemistry, 2000, 68[6], 531-3