Ionic conductivity in single crystals of a 1-dimensional super-ionic conductor was studied by performing alternating-current complex electrical conductivity measurements between 100Hz and 98GHz. The frequency dependence of the complex conductivity exhibited a clear Drude-like behavior in the microwave frequency range. It was suggested that the motion of Cs+ ions could be described by a continuous diffusion model with low friction.

S.Yoshikado, H.Funatomi, I.Taniguchi, M.Watanabe, Y.Onoda, Y.Fujiki: Solid State Ionics, 1996, 86-88[2], 1325-9