Electrical and Dielectric Properties of ZnO-BaO-V2O5 Glasses

The relationship between composition, structure, and electrical properties is essential for understanding charge transport in vanadate glasses. In this study, the influence of ZnO concentration and thermal treatment on the structure, electrical conductivity, and dielectric relaxation of xZnO–(35 − x)BaO–65V2O5 glasses (x = 0–20 mol%) was systematically investigated. Two series of glasses, as-quenched and annealed, were prepared by the melt-quenching technique and characterized by temperature-dependent direct current (DC) conductivity, broadband dielectric spectroscopy, and Raman spectroscopy. The DC conductivity exhibited Arrhenius behavior with two thermally activated conduction regions. Annealing reduced the activation energy at higher temperatures, indicating structural relaxation and stabilization of the glass network. Dielectric spectroscopy revealed two distinct relaxation mechanisms over the frequency range of 0.1 Hz–100 kHz, whereas thermal treatment had only a minor influence on the dielectric relaxation behavior. Raman spectra showed that ZnO progressively modifies the vanadate network through the formation of V–O–Zn linkages while preserving the characteristic terminal V=O bonds. Annealing enhanced the short-range structural ordering without altering the fundamental glass structure. Among the investigated compositions, the glass containing 7 mol% ZnO exhibited distinct structural and electrical characteristics, suggesting that this composition corresponds to a transition in the structural organization of the glass network. The combined structural and electrical analyses demonstrate a clear correlation between ZnO-induced structural modifications and the charge transport properties of ZnO–BaO–V2O5 glasses.