A batch of zinc borotellurite glasses doped with Li2O, W2O3 and rare earth ions were synthesized with varied composition and investigated for dielectric properties in the frequency range from 50Hz to 15MHz and temperature from 300K to 620K. Electric moduli and impedance were estimated. Dielectric relaxation time from both impedance and moduli data were determined. Activation energy for relaxation time has been determined. Nature of the phase of the glasses has been understood in terms of cole-cole plots. Normalized moduli plots were made to learn temperature dependance of relaxation processes. For the first time, glasses of the present composition have been exposed for detailed dielectric relaxation studies.

No abstract

No abstract

No abstract

Melt quenching technique has been adopted to synthesize a set of borotellurite glasses consisting of ZnO, Li2O, WO3 and Dy2O3, with a varied content of WO3. After confirming their amorphous nature by XRD, they were investigated for dielectric properties over a wide range of freqency and temperature. Observed variations in dielectric parameters with frequency, temperarure and composition suggests the presence of mobility of charge carriers, increase of loss due to ionic migration and involvement of dc conductivity. Single phase and conducting nature of the samples have been obtained by sketching cole-cole plots. DC conductivity estimated from impedance spectra indicated semiconducting nature and its activation energy increased with increase of WO3 concentration. Dielectric relaxation time and its thermal activation energy were determined independently from modulus and impedance and found that the former decreased with increase of temperature and the later increased with WO3 content. Master curves drawn for electric moduli revealed that relaxation mechanism in these glasses is temperature independent.