MODEL FOR THE FAST IONIC-DIFFUSION IN ALUMINA-DOPED LII

Lithium Iodide shows enhanced ionic conductivity when doped with a powder of the insulator, alumina. We extend Landauer's effective medium model to see if the observations are consistent with a high conductivity layer forming on each non-conducting particle. The predictions are consistent with experiment provided one assumes the layer a few hundred Angstroms thick. At the outside, away from the particle, the enhancement of conductivity should fall off slowly, as in Debye-Huckel screening, whereas it is possible a new phase forms close to the insulator surface. © 1979.