Electrical conductivity and dielectric properties of Bi 2O 3–GeO 2–PbO–MoO 3 glasses

Abstract

Glasses having compositions 40Bi 2O 3–20GeO 2–(40− x)PbO– xMoO 3 (where x = 3, 6, 9, 12 and 15 mol%) were prepared by normal melt quenching technique. The density ( d) decreases gradually with the increase of the MoO 3 content in such glasses. This may be due to the lower molecular weight MoO 3 is substituted by a higher molecular weight PbO. The dc conductivity decreases while the activation energy increases with the increase of the MoO 3 content. The dc conductivity in the present glasses is electronic depends strongly upon the average distance, R, between the Mo ions. Analysis of the electrical properties has been made in the light of small polaron hopping model. The parameters obtained from the fits of the experimental data to this model are reasonable and consistent with glass composition. The conduction is attributed to non-adiabatic hopping of small polaron. Dielectric properties (constant ε, loss tan δ, ac conductivity σ ac, over a range of frequency 0.12–100 kHz and temperature 325–650 K and frequency exponent s) of these glasses have been studied.