Dielectric and spectroscopic properties of PbO–Nb₂O₅–P₂O₅:V₂O₅ glass system

Abstract

Abstract PbO–Nb 2 O 5 –P 2 O 5 glasses containing different concentrations of V 2 O 5 ranging from 0 to 1.0 mol% were prepared. A number of studies, viz. differential thermal analysis, infrared, optical absorption, Raman and ESR spectra and dielectric properties (dielectric constant ϵ ′, loss tan δ , a.c. conductivity σ ac over a range of frequency and temperature), of these glasses have been carried out. The results have been analysed in the light of different oxidation states of vanadium ions. The analysis indicates that when the concentration of V 2 O 5 is increased gradually, vanadium ions are observed to exist mostly in the V 4+ state, occupy network‐modifying positions and decrease the rigidity of the glass network. A transformation of NbO 4 to NbO 6 structural units and a decrease in the concentration of PO 4 structural units have also been observed with an increase in the concentration of V 2 O 5 in the glass network. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)