These 2 new O-deficient Aurivillius-like phases were synthesized, and their ionic conductivities were measured by using alternating current impedance spectroscopy. It was found that both O ion conductors exhibited discontinuities in the Arrhenius plots of their ionic conductivity. A phase transition, which was confirmed by means of differential thermal analysis, was consistent with an O vacancy order-disorder transition. At 900C, the conductivities were 0.031 and 0.023S/cm for Bi2Sr2Nb2GaO11.5 and Bi2Sr2Nb2AlO11.5, respectively.

K.R.Kendall, J.K.Thomas, H.C.Zur Loye: Solid State Ionics, 1994, 70-71, 221-4