Physical and electrical studies of tellurite-lead-vanadate glasses doped with CoO

Abstract

This article presents structural, physical and conductivity results on tellurite-lead-vanadate glasses, (PbO)0.3 – (TeO2)0.1 – (V2O5)0.6-x – (CoO)x, (x = 0.05, 0.1, 0.15, 0.20, 0.25, 0.30). XRD spectra indicated non-crystallinity of the samples. Density is found in the range 4.401 g/cm3 – 5.092 g/cm3. Density increased as well as molar volume decreased with respect to increase of CoO content. This reveals shows that the glass network is becoming increasingly congested due to an increase in CoO content. Conductivity variation with temperature in the range 300 K – 523 K inferred semi conductivity behavior. High temperature conductivity is obeyed Mott’s small polaron happing mechanism and low temperature data obeyed Mott’s/Greaves VRH model. High temperature activation energy increased with CoO content in the glasses. Number of states at Fermi level derived from VRH model fits are well within the range quoted for similar glasses.