AC Conductivity and Dielectric Constant of Fast Ion-Electronic Conductor AgI-C

Abstract

The conductivity, dielectric constant and crystal structure of the superionic-electronic conductor AgI-porous carbon composites have been investigated at various temperatures and carbon concentrations (ϕ ≤ 10%). At a fixed temperature, both conductivity and dielectric constant exhibit anomalous variation with ϕ showing maxima of the values. We observed significant differences in the behavior between the superionic (α) phase and insulating (β) phase. By incorporating carbon, the conductivity increases by four times in the β phase and six times in the α phase whereas the dielectric constant increases by five times and eight times respectively. Unlike in the β phase, the conductivity of the α phase exhibits two distinct maxima whereas the dielectric constant exhibits different features of the profiles in different frequency regions in the α phase. Also, the peak value of these properties exhibits power-law dependence on the frequency in both phases but with different values for the exponents.