The conductivity of polycrystalline superionic material was investigated, by means of impedance spectroscopy, over a wide temperature range. A sudden increase in conductivity was observed, at 428K, due to the superionic phase transition. The activation energy for conduction decreased from 0.53 to 0.24eV after the phase transition. The frequency dependences of the complex conductivity, electric modulus and dielectric permittivity spectra were analyzed by using the UDR and KWW approaches, and the parameters derived by using these 2 approaches were compared.

Ionic Conduction and Relaxation in KSn2F5 Fluoride Ion Conductor. M.M.Ahmad, K.Yamada, T.Okuda: Physica B, 2003, 339[2-3], 94-100