Ion dynamics in superionic chalcogenide glasses studied in large frequency and temperature ranges.

Pradel A, Taillades G, Cramer C, Ribes M

Abstract

Elec. cond. measurements on silver thiogermanate glasses were performed in extended temp. (20-600 K) and frequency (10 Hz-60 GHz) ranges. The data indicate three cond. regimes: the d.c. regime with a deviation from Arrhenius law below the glass transition temp., a dispersive region where σ(ω) = Aωs1 (s1 ≈ 0.5 and A is thermally activated with an activation energy E1 ≈ (1-s)Ed.c.) and a 3rd regime where σ(ω)=Bωs2. At T < 100 K the 3rd regime can be accounted for by an asym. double well potential model. The 3rd regime at high frequency (GHz range) and high temp. (>150 K) shows clearly a superlinear frequency dependence. Addnl. measurements are needed to clearly identify the temp. dependence of cond. in this region. [on SciFinder(R)]