A series of "-aluminogallate crystals, (Al,Ga)11(Na,Mg)O17, in which Ga was substituted for Al to the extent of 30 to 52%, was prepared by flux evaporation. The use of X-ray diffraction confirmed that the structure was analogous to that of rhombohedral Na+ "-alumina, and that the a-axis and c-axis lattice parameters increased with increasing Ga content. Two-point alternating current impedance measurements indicated that the Na+ "-aluminogallates were fast ion conductors with conductivities (0.36 to 1.18S/cm at 300C) which were equal to, or slightly lower than, that of Na+ "-alumina. The activation energies were also comparable. In spite of an increase in c-axis lattice parameter, the conductivities of the Na+ aluminogallates became somewhat lower as the c-parameter increased.

T.A.Faltens, B.Dunn: Solid State Ionics, 1993, 66, 321-9