Formulation of conductivity, electric modulus and dielectric behaviour of calcium bismuth borovanadate glasses with varying temperature and frequency

Abstract

This study explores various glass compositions within calcium bismuth borovanadate glass system, produced through melt quenching. The investigation focuses on AC conductivity, electric modulus formulation, and dielectric properties (ε′ and ε″). The AC conductivity and dielectric constants exhibit an increasing trend with rising CaO content until 10 mol%, followed by a decline for x = 15 and x = 20 mol%. Temperature and frequency-dependent conductivity reveal a dual plateau between 423 K and 523 K. The Almond west model is applied to fit AC conductivity data, extracting parameters such as direct current conductivity, crossover frequency, and frequency exponent. The glass samples demonstrate diverse conduction mechanisms, including small polaron quantum mechanical tunnelling and CBH conduction. The activation energy values for direct current conduction (Edc) ranging from 0.539 to 0.716 eV (at lower freq.) and electric modulus (ER) (0.531 to 0.707 eV) is nearly identical. Non-Debye type behaviour is reflected by dielectric studies.