Electrical conduction and dielectric properties of Bi2O3–B2O3–TeO2 glass

Amorphous bulk bismuth boron tellurium glass system of compositions (Bi2O3) x (B2O3)0.5−x (TeO2)0.5 with x = 0.05, 0.1, 0.2, 0.3 and 0.4 is prepared using melt quenching method. The ac and dc conductivities (σ ac and σ dc) of as-prepared samples are measured in the temperature range 303–373 K and displayed dielectric dispersion in the frequency range 100 Hz–5 MHz. The ac conductivity versus frequency plots were analyzed by considering a power law: σ ac α ω s(s ≤ 1). A comparison between values of the index s with those numerically calculated from different conduction models revealed that correlated barrier hopping is a fairly good model to describe the dominant ac conduction mechanism in the studied compositions. Besides, results of the real dielectric constant (e′), loss factor (e″), and loss tangent (tan δ) together with the optical (e ∞) and static (e s) dielectric constants, estimated from Cole–Cole diagrams, for the studied samples are given and discussed. Temperature dependence of the frequency exponent s for the studied amorphous bulk samples obtained from slopes of the relation ln σ ac = f(T). The solid curves represent the values calculated using the models: QMT, NSPT, and OLPT. The dashed curve represents the CBH model, which gives a fairly good fit with the experimental results (symbols) .