It was found that perovskite compositions in these systems had high electronic and ionic conductivities. An appreciable reversible weight loss was observed at high temperatures, as the materials became increasingly O-deficient. This loss of lattice O at high temperatures, which tended to increase with increasing acceptor content, resulted in a decrease in the electronic conductivity. In an O partial pressure gradient, the O flux through dense sintered membranes of the materials was highly dependent upon the composition, and increased with increasing temperature. The increase in O flux with increasing temperature was attributed to increases in the mobility and concentration of lattice O vacancies. The calculated ionic conductivities of some compositions were higher than that of yttria-stabilized zirconia.

J.W.Stevenson, T.R.Armstrong, R.D.Carneim, L.R.Pederson, W.J.Weber: Journal of the Electrochemical Society, 1996, 143[9], 2722-8