Influence of WO₃ on dielectric properties of zinc phosphate glasses

Abstract

275-284Dielectric constant ɛ', loss tan δ and a.c conductivity σa.c of 40 ZnO-xWO3-(60-x) P2O5 (with 0 ≤ x ≤ 15) glasses are studied as a function of frequency (in the range 102-105 Hz) and temperature (range 30-300°C). The dielectric breakdown strengths of these glasses are also measured in the air medium. All the dielectric parameters (viz., ɛ', tan δ and σa.c) are found to decrease with the increase in the concentration of WO3. Dielectric loss variation with the temperature for the glasses containing WO3 up to 5 mol % exhibited dipolar relaxation effects. These effects are analysed by a pseudo Cole-Cole plot method. The dielectric breakdown strength, the activation energy for a.c conduction are found to decrease with increase in concentration of WO3. These results have been used to throw some light on the structural change in ZnO-WO3-P2O5 glass system with the aid of data on IR spectra and differential thermal analysis of these glasses