A microscopic model was developed for the mixed-alkali effect in crystals of - or ”-alumina. It was based upon the formation of certain mobile defects, and the fact that different types of mobile ion had differing tendencies to become part of these defects. Computer simulations of the ionic conductivity were found to be in excellent agreement with experimental data. The model predicted a common shape for the re-scaled conductivity isotherms; regardless of the temperature and the specific type of probe. This was also in agreement with available experimental results.

M.Meyer, V.Jaenisch, P.Maass, A.Bunde: Physical Review Letters, 1996, 76[13], 2338-41