Electrical properties of lead vanadate glasses

Abstract

Electrical properties of different compositions of lead vanadate glasses are reported in the temperature range 80–500 K. The experimental results are analyzed with reference to theoretical models existing in the literature. It has been observed that at high temperatures, Mott’s model of phonon-assisted small polaron hopping between nearest neighbors is consistent with the data, while at low temperatures the variable-range-hopping model is valid. The hopping at high temperatures in the lead vanadate glasses occurs by the nonadiabatic process in contrast to the vanadate glasses formed with conventional network formers. The hopping model of Schnakenberg can predict the temperature dependence of the conductivity data. The percolation model of Triberis and Friedman applied to the small-polaron-hopping regime is also consistent with the data. The consistency of the low-temperature data with the predictions of the different models cannot be distinguished. The various model parameters such as localization length, density of states, etc., obtained from the best fits are found to be consistent with the glass compositions.