DC conductivity of V2O5-PbO-TeO2 glasses and the effect of pressure

The dc conductivity of V2O5-PbO-TeO2 glasses was investigated from 300 to 473 K, and the effect of pressure on conductivity was studied to 6 GPa. Glasses were found to be n-type semiconductors with conductivity sigma = 1.5 X 10(-6)-1.2 X 10 S-4 cm(-1) at 408 K. The conduction was confirmed to be due to small polaron hopping between vanadium ions and was adiabatic for V2O5 = 40-70 mol%. The carrier density determined was 0.96-3.18 X 10(21) cm(-3). Estimated carrier mobility was from 8.61 X 10(-9) to 1.02 X 10(-7) cm(2) V-1 s(-1). The dominant factor determining conductivity was mobility in these glasses. The application of pressure to 6 GPa increased conductivity about a factor of 2-4. Reversible changes in conductivity on applying or releasing pressure were observed and attributed to variations in vanadium ion spacing, R, assuming small polaron hopping conduction in compacted glasses.