Solid solutions of a highly A-site deficient perovskite of the form, Yx(Ta3xW1-3x)O3, where x was between 0 and 0.33, were prepared via solid-state reaction. They were found to exhibit a high trivalent ionic conductivity. The crystal structure changed from a Y-ordered superstructure, to a disordered structure, with decreasing x-value. The high trivalent ionic conductivity was observed in the disordered structure. A solid solution with x = 0.06 exhibited the highest conductivity, of 2.58 x 10-5S/cm at 635K. The polarization data strongly suggested that Y3+ ions were the main mobile species. The ionic transfer number of samples with x = 0.06 was found, from direct-current polarization measurements, to be greater than 98%.

Trivalent Ionic Conductivity of Perovskite-Type Y(Ta,W)O3. N.Sakai, K.Toda, M.Sato: Electrochemistry, 2000, 68[6], 504-6