Electrical behaviour of BaO-substituted multicomponent (K2O-P2O5-Na2O-CaO-B2O3) bioactive Glasses

Abstract

Multicomponent glasses with composition xBaO-2K₂O-2P₂O₅-27Na₂O-21CaO- (48-x)B₂O₃ (x = 0, 2, 4, 6 & 8 mol%) has been prepared through melt–quench technique. X-ray diffraction (XRD), dielectric measurements, equivalent circuit analysis, ac and dc conductivity have been investigated. XRD profiles revealed that the produced samples were amorphous in nature. Dielectric parameters such as ε′, ε″ and tanδ showed decreasing behaviour with rise in frequency. Nyquist plot attributed the relaxation to non-Debye type. The electric behavior of the samples was further studied using an equivalent circuit analysis corresponding to the Nyquist plot. The ac conductivity of prepared samples followed Jonscher’s power law (JPL) and was observed to follow overlapping large polaron tunneling (OLPT) model. The semiconductor-like behaviour of the produced glasses is confirmed by the variation in dc conductivity with temperature. The dc conductivity results were analyzed using Arrhenius relation, which revealed high activation energies (> 1 eV) for all synthesized glasses and the Arrhenius plot's linearity is not deviated, which primarily illustrates the ionic conduction process.