A frequency response analysis was made of the impedance, conductivity (table 1) and modulus of a series of compositions in a mixed system which exhibited Ag ionic conductivity at temperatures ranging from 290 to 400K (65.5kHz to 1Hz). The frequency-dependent conductivity spectra were found to obey the Jonscher power law within the present temperature range. The observed temperature dependence of the conductivity indicated that a low activation energy was associated with the composition which exhibited a high conductivity, and vice versa. A separation of the grain-boundary and electrode polarizations, from the bulk impedances, was made possible via the impedance spectra. A long tail in the low-frequency region, and a tendency to peak at higher frequencies in the modulus diagram, showed that it was feasible effectively to suppress information concerning grain-boundary and electrode effects in the modulus formalism. The modulus and impedance spectra revealed a non-Debye type of polarization in the present material.

A.Viswanathan, S.A.Suthanthiraraj: Materials Research Bulletin, 1993, 28[5], 821-8

Table 1

Ionic Conductivity of Ag2CrO3-CuI Compositions