Effect of transition metal and alkali oxides on structural, optical and dielectric properties in Zinc-Phosphate amorphous glassy systems

Abstract

The influence of transition metal and alkali earth metal oxide on the structural, optical and dielectric properties of inorganic glasses prepared by melt quenching method, having chemical composition 0.35ZnO0.25P2O5-(0.4-x) Na2O-xV2O5 (0.05≤x≤0.25), have been studied. The Rietveld Refinement of the XRD spectra confirms the presence of Na3P8VO23 and Zn2V2O7 nanocrystallites. Raman spectroscopy has been deployed to identify and quantify the individual phases present within the glass matrix. The optical bandgap energy values, which are obtained from the UV–Vis spectra, vary with V2O5 concentration (x), and an inverse association between the optical bandgap and Urbach energy has been demonstrated. The absorbance and reflectance spectra have been investigated, and several optical parameters, such as the excitation and absorption coefficients, refraction index, polarizability, SELF and VELF functions, etc., have also been examined. The dielectric constant and dielectric loss decrease with the increase in frequency but increase with the rising temperature. The dielectric properties have been examined at various temperatures and frequencies. The analysis of the scaling property of electric modulus indicates the conductivity or dielectric relaxation mechanisms, which is temperature independent and composition-dependent. The estimated value of the exponent parameter from Bergman's function being less than unity confirms the non-Debye type relaxation process occurring within the transition metal and alkali oxide doped zinc-phosphate glass matrix.