Solid State Ionics, Vol.189, No.1, 33-38, 2011
Electrical conduction in (La0.97Sr0.03)(2)(Mo1-xGax)(2)O9-alpha ceramics
A novel series of ceramic samples (La0.97Sr0.03)(2)(Mo1-xGax)(2)O9-alpha (x=0, 0.01, 0.03, 0.05, 0.08) were prepared by a solid-state reaction method. All the doubly doped ceramics have a single cubic structure except (La0.97Sr0.03)(2)(Mo0.92Ga0.08)(2)O9-alpha. The conduction behaviors of the samples with x <= 0.05 were investigated using various electrochemical methods including gas concentration cells, oxygen electrochemical permeation and AC impedance spectroscopy in the temperature range of 823-1273 K. In dry oxygen-containing atmosphere, the ceramic samples were almost pure oxide-ionic conductors. In wet oxygen-containing atmosphere, the ceramic samples were also almost pure oxide-ionic conductors, but didn't possess the protonic conduction. The electrochemical oxygen permeation experiment further verified the oxide-ionic conduction nature under oxygen-containing atmosphere. The phase transition has been completely suppressed in the doubly doped samples in both dry and wet air atmospheres. The oxide-ionic conductivities were affected by the doping levels, and increased in the order: sigma (x=0.05)