Studies on the influence of V2O5 on dielectric relaxation and ac conduction phenomena of Li2O-MgO-B2O3 glass system

Li2O-MgO-B2O3 glasses containing different concentrations of V2O5 ranging from 0 to 1.5 mol% are prepared. Dielectric properties, viz., constant epsilon', loss tan delta, ac conductivity sigma(ac) over a range of frequency and temperature and breakdown strength in air medium have been studied; the values of epsilon', tan delta and sigma(ac) are found to increase with the increase in the concentration of V2O5 up to 1.0 mol% and beyond this concentration, these values are found to decrease gradually. The results have been analyzed with the aid of data on a number of other studies, viz., optical absorption, ESR spectra, IR spectra and magnetic susceptibility of these glasses. The observed dielectric relaxation effects are described by the Classius-Mosetti Debye relation with a set of relaxation times, and the ac conduction process in the glasses has been explained on the basis of the correlated barrier-hopping model. (C) 2003 Elsevier B.V. All rights reserved.