Influence of valence states and co-ordination of cobalt ions on dielectric properties of PbO–Bi2O3–As2O3:CoO glass system

The glasses of the composition (40−x) PbO–15Bi2O3–45As2O3–xCoO, with 0≤x≤0.6 mol% in the steps of 0.1 were synthesized. The dielectric properties viz., dielectric constant, loss and ac conductivity over moderately larger ranges of frequency and temperature were investigated. The results were analyzed with the aid of the data on optical absorption and IR spectra. The analysis indicated that there is an increase in the insulating strength of the glasses with increase in the concentration of CoO up to 0.4 mol%.