Impact of Bi₂O₃ doping on micro/nano-mechanical and dielectric properties of Fe₂O₃–P₂O₅–V₂O₅ quaternary glass systems

This paper thoroughly investigates the synergistic effects of Bi₂O₃ incorporation on adjusting the mechanical and dielectric properties of Fe₂O₃-P₂O₅-V₂O₅ glasses prepared through the melt quenching method. The microhardness, nano-hardness, and dielectric properties of glasses with varying Bi₂O₃ contents (x = 0, 0.1, 0.2, 0.3, and 0.4) were examined in detail to understand how temperature- and frequency-dependent network modifications are induced by Bi₂O₃. Evidence of enhanced micro- and nano-hardness in the developed glasses with Bi₂O₃ addition was observed during mechanical testing. Microhardness ranges from 182 Hv at x = 0.0 to 766 Hv at x = 0.4, while nano-hardness varies from 191.52 Hv to 828.67 Hv, reflecting densification and improved atomic packing within the glass matrix. An improvement in elastic modulus with increasing Bi₂O₃ content was also noted. These structural enhancements further influenced dielectric properties, revealing a correlation between structural stiffness and dielectric response. The dielectric constant (ε^/) increased at low frequencies and remained stable with temperature, showing a 15 % rise at 413 K; dielectric loss (ε^//) indicated effective dipole relaxation at low frequencies, with optimal performance at x = 0.3. Ionic mobility and energy barriers, evaluated through dielectric relaxation activation energy, decreased from 0.67 eV (x = 0.1) to 0.49 eV (x = 0.4). Electrical modulus plots confirmed non-Debye relaxation behaviour; loss modulus peaks shifted to higher frequencies with increased Bi₂O₃ content. Overall, this research demonstrates that Bi₂O₃ and Fe₂O₃ enhance the mechanical stability and dielectric performance of the glass matrix due to their structural compatibility.