Consequence of the heat-treatment on the ionic conductivity of silver-tellurite glass nanocomposites

Abstract

Ion conducting tellurite glass of the composition 0.60AgI-0.40(0.45Ag2O-0.55TeO2) has been prepared by melt quenching technique. Controlled heat treatment has been applied on the as-prepared sample for 12 h, 24 h, and 48 h duration, respectively. X-ray diffraction patterns reveal that the base sample is amorphous and heat-treated samples exhibit the presence of nanocrystallites. The size of the crystallites increases with the increase of the duration of heat treatment. The Ag+ ion dynamics has been investigated over wide temperature and frequency ranges, and the frequency dependent conductivity data have been analyzed in the context of Almond-West formalism. The temperature dependence of the dc conductivity and the crossover frequency shows a different kind of behaviour in contradiction to that observed in other ion conducting glasses. The samples do not follow the Barton-Nakajima-Namikawa relation. With increasing heating hour, the ionic conductivity of the heat-treated samples falls in consequence of the formation of agglomerated grains. Deviation from the time-temperature superposition principle for the conductivity spectra has been observed for these samples.