The alternating-current characteristics of a 2-dimensional randomly-filled square R-C network were shown to exhibit many features which were the same as those of a typical ionic conductor. These included the so-called universal power-law frequency responses of alternating-current conductivity and permittivity. It was suggested that a random network of ion-conducting channels and insulating islands could provide a realistic model for the conducting paths within a bulk ionic conductor. The direct-current ionic conductivity was identified with a resistive percolation path through the network, and the higher-frequency power law component was identified with that of the random network of alternating-current conducting linked capacitive and conductive regions. The dielectric loss peak which was associated with ionic conductors was also found to be a random R-C network-characteristic. The effect of insulating islands which had a Debye-like capacitance was modelled, and ZrO2-12mol%Y2O3 data were presented which exhibited the predicted effects.

An Evaluation of Random R-C Networks for Modelling the Bulk ac Electrical Response of Ionic Conductors. B.Vainas, D.P.Almond, J.Luo, R.Stevens: Solid State Ionics, 1999, 126[1-2], 65-80