Preparation and a.c. conductivity studies of CaF2-LiF composites

A new fluoride ion conducting composite CaF2-LiF was synthesized by an arc-melting technique and characterized by X-ray and complex impedance analysis. A conductivity enhancement of about three orders of magnitude 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. Jonscherʹs universal power law relation, σ(ω)=σ(0)+Aω‰ was used to explain the observed frequency dispersion of conductivity. The conductivity parameters such as power law exponent n, relaxation time τ and activation energy for relaxation Eτ were calculated and the results are reported.