Tailored structures and dielectric traits of holmium ion-doped zinc-sulpho-boro-phosphate glass ceramics

Abstract

Customisation of the lasing characteristics of rare-earth ions activating various materials for practical applications requires fundamental knowledge of the structure and dielectric correlation. Based on these factors, a new series of glass ceramics of composition (40-x)P2O5 –30B2O3 –30ZnSO4 –xHo2O3 (x = 0.0, 0.4, 0.5, and 0.6 mol%) were prepared using the melt-quenching method. As-prepared samples were characterised using various techniques to determine the effect of holmium ion (Ho3+) doping on their structure and dielectric traits. XRD patterns of as-quenched samples confirmed their glass-ceramic characteristics. Holmium ion concentration-dependent Raman and FTIR analyses revealed the structural enhancement in the glass ceramics. The presence of Zn, S, B, P, O, and Ho in the glass ceramics was disclosed by the XPS spectra, and the ratio of the bridging to non-bridging oxygen atoms was evaluated by analysing the O1s peaks. The recorded room temperature complex impedance spectra of the samples in the range of 103–105 Hz were influenced by the predominant glassy and dormant crystalline structures. The UV–Vis–NIR data (in the range of 206–310 nm) and the impedance spectra (3×1012–3×1014 nm) were analysed to evaluate the dielectric features of the samples. The considerable increase in the frequency-dependent AC conductivity and its slight reduction with Ho3+ incorporation was ascribed to the dopant ion-induced formation of quasi-molecular complexes (such as bridging oxygen and ligands) in the host network. A correlation between the structure and dielectric attributes of the titled glass ceramics was established. In short, the Ho3+-incorporated customised structures and dielectric properties of the newly proposed glass-ceramic composition were affirmed to be prospective for sundry applications.