Model of polarization conductivity in ionically conducting glasses

Abstract. We have used a hopping conduction model to calculate the frequency-dependent polarization conductivity, d(w) in ionically conducting glasses, and we have assumed that a short-range ionic hopping mechanism occurs based on a fluctuation process. We have underlined the fundamental differences between the frequency-dependent polarization conductivity due to "bound-charge " and the dc conductivity related to "free-charge " diffusion. The law AwS is observed as for electronic charge-carriers in amorphous substances. The expression of parameter s is modified by the introduction of a term connected with the fluctuation probability. A plot of the function T11-s = f(T) shows a striking difference in behaviour (slopes) between ionic glasses (Na,O-3Si02, (ASS), (GeS2),-,) and electronic amorphous solids. 1) Introduction. The use of ionic conducting glasses has been a subject of great interest for ten years (1, 2), and charge motion processes in these solids have been the matter of many investigations (3, 4). A well-known experimental technique has been frequently used to study these kind of solids: complex impedance spectroscopy (5). Originally it allowed information on the direct current conductivity measured on ionic conductors to be obtained (6)