Electrical characterization of lead-modified bismuth borovanadate glasses

Abstract

Specifically, the study looks into dielectric characteristics (ε′andε″) and complex modulus formulation and AC conductivity of lead-modified bismuth borovanadate glasses (50-x) V2O5-40 B2O3-10 Bi2O3-xPbO, where x = 5,10, 15, 20 and 25 mol% with sample ID's VPb1, VPb2, VPb3, VPb4 & VPb5 according to different compositions of lead and vanadate. When the PbO content rises, there is a decreasing tendency in both the alternating current conductivity and dielectric constants. In order to fit AC conductivity data, Almond West equation is used to extract parameters, including crossover frequency (ωH), frequency exponent (s), and direct current conductivity (σdc). Direct current conduction mechanism in all glass samples except VPb5 [Correlated Barriers Hopping (CBH) conduction at all frequencies] at lower frequencies might potentially be attributed to large-polaron quantum mechanical tunneling (LQMT). Similar to this, at high frequencies, small polaron quantum mechanical tunnelling is followed by VPb2 & VPb3 while LQMT is followed by VPb1 & VPb4. Activation energy of dc conduction (Edc) at higher frequencies (0.373–0.476 eV) for samples having sample ID VPb1 to VPb4 and sample VPb5 at all frequencies with Edc 0.686 eV and modulus activation energy (ER) (0.382–0.534 eV) are found in good agreement. Dielectric studies reveal non-Debye-type behaviour.