PREPARATION AND AC CONDUCTIVITY STUDIES OF CAF2-LIF COMPOSITES

A new fluoride ion conducting composite CaF2-LiF was synthesized by an are-melting technique and characterized by X-ray and complex impedanc e analysis. A conductivity enhancement of about three orders of magnit ude was obtained as a result of dispersing LiF in the CaF2 matrix. The observed conductivity enhancement was interpreted on the basis of the space charge model for ionic conduction. Jonscher's universal power l aw relation, sigma(omega) = sigma(0) + A omega'' was used to explain t he observed frequency dispersion of conductivity. The conductivity par ameters such as power law exponent n, relaxation time tau and activati on energy for relaxation E(tau) were calculated and the results are re ported.