Spectroscopic, dielectric dispersion and dc conductivity studies of Sb2O3doped lithium fluoro borophosphate glasses mixed with small concentrations of NiO

Abstract

Glasses of the composition(20–x) LiF–10 Sb2O3–10 B2O3–60P2O5: x NiO(0 < x < 0.25) were synthesized by conventional rapid melt quenching method. The non–crystalline nature of the samples was confirmed by XRD analysis and the glass forming abilities were analyzed by DTA studies. The compositional dependence of structural aspects of the glasses was analyzed by FT–IR and Raman studies. The DTA, FT–IR and Raman studies suggested an increasing degree of disorder in the glass network with increasing concentration of NiO up to 0.20 mol %. The reversal trend observed beyond 0.20 mol% is attributed to an increasing polymerization of glass network. The optical absorption (OA) and photoluminescence (PL) studies were also carried on these glasses. The results of OA and PL spectral studies suggested that the gradual increase of octahedral Ni2+ ions with the increase in the concentration of NiO up to 0.20 mol%. Electrical properties viz., dielectric dispersion, DC and AC conductivity of the titled glass samples were also performed on titled glass samples. The observed increase in the values of dielectric constant, dielectric loss and AC conductivity (at any frequency and temperature) with the increase in the concentration of NiO up to 0.20 mol%is ascribed to the increasing space charge polarization in the glass network. The results of conductivity studies indicated that there is a mixed conduction (both ionic and polaronic) and the polaron hopping seems to prevail over ionic conduction in the glasses containing less than 0.20 mol% of NiO.