A comparison of the conductivities of NaCl single crystals and NaCl-Al2O3 composites revealed the expected enhancement due to the presence of Al2O3 particles. The self-diffusion of Na+ exhibited a similar enhancement in the extrinsic range as well as in the intrinsic high-temperature region. The correlation factor was deduced from the Nernst-Einstein relationship. The value of 0.78 showed that mass transport in the composite proceeded via the same mechanism as in the unmixed ionic crystals. That is, via Schottky defects.

F.Bénière, K.V.Reddy: Journal of the Physics and Chemistry of Solids, 1999, 60[6], 839-47