Dynamics of silver ions in AgI doped Ag2O-SeO2-MoO3 mixed former glasses.

Abstract

We have studied the dynamics of silver ions in AgI-doped Ag2O-SeO2-MoO3 mixed former glasses in wide frequency and temperature ranges. We have observed that the ionic conductivity exhibits a mixed glass network former effect for low AgI content. The scaling for the conductivity spectra shows that the mechanism of charge carrier dynamics is independent of temperature and composition. We have obtained a mobile Ag+ ion concentration from the Nernst-Einstein relation, which is found to be independent of temperature, but slightly dependent on composition. We have also obtained the characteristic mean square displacement of the silver ions from the mapping of the conductivity spectra in the time domain. It is observed that the composition dependence of the characteristic displacement is opposite to that of the conductivity. We have also studied the influence of the network structure of these glasses on ion dynamics using infrared spectra and established a correlation between the ion dynamics and the SeO32- structural units. It is observed that the available hopping sites for Ag+ ions increase in the glass network with the increase of non-bridging oxygens of SeO32- units.