Studies of Anomalies in Mixed Conduction of Na<sub>2</sub>O and V<sub>2</sub>O<sub>5</sub> Doped Boro-Phosphate Glasses

Abstract

A set of borophosphate glasses doped with alkali and transition metal (TM) ions have been synthesized. The glasses were carried through; annealing, XRD, density, DC conductivity studies. Molar volume and density varied nonlinearly. High temperature activation energy is analysed taking into consideration of Mott’s SPH model. The low temperature electrical conductivity was analysed by Mott and Greaves VRH. Several polaron hopping related parameters at high temperature region and density of states at low temperature region were computed. The high temperature DC activation energy measured by conductivity, calculated numerous pertained parameters varied nonlinearly with mole fraction of vanadium content. The Study exhibits DC electrical conduction is due to both alkali and transition metal ions and thus confirms the mixed conductivity. A crossover conduction mechanism from the ionic dominant region to polaronic predominant region has been also observed. Studies revealed the single transition effect at 0.4 mol fraction of V2O5 content.