DC conductivity and hopping mechanism in V2O5-B2O3-BaO glasses

The dc electrical conductivity of 60 V2O5-(40 - x)B2O3-xBaO (x = 15, 20, 25, 30 and 40 mol%) glasses is reported in the temperature range 300-523 K. The physical and transport properties such as density, number of ions per unit volume, hopping distance, polaron radius and activation energy are reported. The electrical data are analysed in the light of the models of polaronic hopping conduction. The analysis shows that the high-temperature conductivity is well explained by polaronic models. The methods suggested by Holstein and by Sayer and Mansingh are applied to the determination of adiabatic or nonadiabatic hopping conduction. It is observed that in this system nonadiabatic hopping conduction is present. The hopping distance evaluated as 3.479-3.831 Angstrom increases with decreasing BaO content. The values of the decay constant and the density of states are reasonable for the localized states.