Investigation of electrical and impedance spectroscopic properties of Na2O modified lead-bismuth borate glasses

Abstract

Sodium-substituted lead-bismuth borate glasses, prepared using the melt-quench technique, have been investigated for their AC conductivity, modulus formulation, and impedance spectroscopy analysis. The direct current conductivity $\left({\sigma }_{dc}\right)$, crossover frequency $\left({\omega }_H\right)$, and frequency exponent (s), derived from fitting AC conductivity data with the Almond–West power law, gives information about the conduction mechanisms of the glasses. All samples exhibit AC conduction via the correlated barrier hopping (CBH) model. As the Na₂O content increases, the AC conductivity also increases. The imaginary part of the electric modulus ($M{}^{″}$) follows the non-exponential Kohlrausch-Williams-Watts (KWW) function, highlighting composition-dependent and temperature-independent behavior. Impedance investigations were conducted using equivalent circuit models to accurately fit the Nyquist and Bode plots for each sample across the temperature range under consideration. Activation energy values obtained from conductivity (1.155–0.891 eV), electric modulus (1.255–0.899 eV), and impedance (1.206–0.931eV) measurements were found to be nearly identical.