PREPARATION AND CONDUCTIVITY OF BA2IN2O5 CERAMICS

Sintered bodies of (Ba,Pb)(2)In2O5 were prepared by substituting A sit e of Ba2In2O5 having a brownmillerite-related structure with Pb. Cryst al structure and conductivity of sintered (Ba,Pb)(2)In2O5 were investi gated. The crystal structure of (Ba,Pb)(2)In2O5 was governed by the Pb content, and changed from orthorhombic to cubic structure with an inc rease in Pb content. The temperature dependence of the conductivity of (Ba,Pb)(2)In2O5 revealed that the order-disorder transition of oxygen vacancy disappears with an increase in Pb content, and that oxygen va cancies are disordered even at room temperature to have cubic structur e. (Ba0.80Pb0.09)(2)In2O5 showed higher conductivity than Ba2In2O5 in the temperature range of 613 to 1100 K. The results suggest that the c hanges in crystal structure and conductivity are due to the ionic pola rization of Pb.