Ion transport and relaxation studies of silvervanadotellurite glasses at low temperatures

Quaternary silvervanadotellurite (SVT) glasses of various formers compositions (x) 60%AgI-26.67%Ag2O-13.33%[(1−x)V2O5 +(x)TeO2]; x = 0.0–1.0 in steps of 0.1 were prepared by a melt quenching technique. All the prepared SVT glasses were characterized by X-ray diffraction, FTIR and DSC measurements to confirm the glassy/amorphous nature, incorporation of tellurite in vanadium oxide glassy matrix and their glass transition temperature (Tg), respectively. Complex impedance measurements were made at room temperature (RT) as well as low temperatures (99–242 K) on SVT glasses and impedance data were analyzed using the Boukamp equivalent circuit software to obtain conductivity at each temperature. Low temperatures conductivity studies were made only for the high conducting composition (x = 0.6) of SVT glasses. Activation energy (Ea) is obtained from Arrhenius plots of temperature dependent dc conductivity and it is found to be 0.25 eV for high conducting SVT glass. The ac conductivity was calculated using the impedance data of SVT glass measured at low temperatures and analyzed with Jonscher’s Universal Power law (JUP). The obtained power law exponent s for the SVT glass was found to exhibit a non-linear behavior with temperature and its nature of ion relaxation was explained using the DCR model. The dielectric and electric modulus (M∗ = M′ + iM″) data was calculated using impedance data for the x = 0.6 composition of SVT glass measured at low temperatures.