Study of electric transport and impedance analysis in copper chloride modified bismuth boro-tellurite glasses

Abstract

CuCl₂ substituted bismuth borate tellurite glasses were examined for electrical conductivity at frequencies between 10⁻¹ Hz and 10⁶ Hz and temperatures between 463 K and 563K. The Almond West law used for fitting experimental data of ac conductivity, and determining cross-over frequency (ω_H), frequency exponent (s), and dc conductivity (σ_dc). Depending on the glass composition, ac conduction process was modeled using correlated barrier hopping and non-overlapping small polaron tunneling. The imaginary component of the electric modulus included in the experimental data fitted by non-exponential Kohlrausch-Williams-Watts. Impedance examination reveals minimization of mixed former effect on electric charge transport at low frequencies in studies glasses. For x = 20, conduction occurs due to charge carriers (Cu²⁺ ions/polarons). An excellent match is found between the Nyquist plots and equivalent circuit models. There is good agreement between the estimated activation energy from conductivity E_C (0.82–1.13 eV), electric modulus E_R (0.81–1.12 eV), and impedance E_Z (0.82–1.15 eV) analyses.