Frequency dependence of conductivity in superionic conducting chalcogenide glasses

Abstract A good understanding of phenomena related to ionic transport in glasses is still lacking. The most recent models proposed to describe microscopic processes of ion motion in glasses are based upon the observed dependence of conductivity of frequency. This dependence is generally described by the so called ‘universal’ law: σ ac = σ sdc + Aω s In this work, electrical conductivity measurements on superionically conducting chalogenide glasses of the Ag 2 S-GeS 2 -AgI family were performed from the microwave region (6 GHz) down to audiofrequencies (1 KHz) in the temperature range (200–300 K). In this case, the observed dependence of conductivity on frequency cannot be described by the universal law but rather by a more complex law of type: σ(ω)=σ dc + Aω s + Bω s t where 0 s s ′ ⩾ 1. Parameters A and B are thermally activated. Whereas parameter B is weakly thermally activated, activation energy of A , E ac , can be related to dc activation energy of E dc = (1 − s ) E dc′ .