Electrical conductivity and relaxation phenomena in Li2O·B2O3 based glass and glass-ceramic: A comprehensive and comparative analysis

This work reports a detailed investigation on the electrical conductivity and dielectric relaxation phenomena in Li2O·B2O3 based glass and glass-ceramic materials. Measurements reveal that the electrical conductivity of glass-ceramic is lower than glass. This owes to occurrence of grain boundaries which impede the mobility of charge carriers in glass-ceramic as confirmed by FESEM micrographs. The frequency-dependent behavior of electrical conductivity, within the measured temperature range, is analysed using Jonscher's power law. It is found that the conductivity rises with an increase in temperature and the range of conductivity reveals the semiconducting behavior of the material. The ac conductivity mechanism of system is observed to follow the overlapping large polaron tunneling model. The conduction and relaxation mechanism studies are performed using electric modulus and impedance spectroscopy within the frequency and temperature ranges varied from 103 Hz to 107 Hz and 593 K–773 K, respectively. Analysis of the relaxation mechanism in both samples is performed employing Kohlrausch-William-Watts (KWW) model, which reveals that the charge carriers are following non-Debye type relaxation. To distinguish between the contribution of grain boundaries and grains in the relaxation mechanism, a combined analysis of complex electric module and impedance spectroscopy has been discussed.