engleski

Electrical Mobility of Silver Ion in Ag2O−B2O3−P2O5−TeO2 Glasses

The effect of adding TeO2 into (100 − x)[0.5Ag2O − 0.1B2O3 − 0.4P2O5] − xTeO2, with 0−80 mol % TeO2 glass, on the structural changes and electrical properties has been investigated. DSC and thermodilatomery were used to study their thermal behavior, structure was studied by Raman spectroscopy, and electrical properties have been studied by impedance spectroscopy over a wide temperature and frequency range. The introduction of TeO2 as a third glass former to the glass network causes the structural transformation from TeO3 (tp) to TeO4 (tbp) which contributes to the changes in conductivity. The glasses with low TeO2 content show only a slow decrease in dc conductivity with addition of TeO2 due to the increase of the number of nonbridging oxygens, which increases the mobility of Ag+ ions. The steep decrease in conductivity for glasses containing more than 40 mol % TeO2 is a result of decrease of the Ag2O content and stronger cross-linkage in glass network through the formation of more Te−eqOax−Te bonds in TeO4 tbp units. The glasses obey ac conductivity scaling with respect to temperature, implying that the dynamic process is not temperature dependent. On the other hand, the scaling of the spectra for different glass compositions showed the deviations from the Summerfield scaling because of the local structural disorder which occurs as a result of the structural modifications in the tellurite glass network.

Borophosphate glass; Silver-ion mobility; Electrical modulus

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