Structural Investigations of Lithium Bismuth Borate Glasses Doped With Nickel Ferrite

Lithium bismuth borate glasses doped with nickel ferrite were synthesized with composition 20Li(2)O center dot xBi(2)O(3)center dot(80-x) B2O3 + (2.0 mol%) NiFe2O4 (x =0, 10, 20, 30 and 35 mol%) via melt quench technique. Glassy nature of prepared samples was confirmed through peak free XRD patterns. Compositional dependence of change in glass structure (using FTIR spectra), optical hand gap and Urbach's energy (UV-Vis-NIR spectra) were discussed. Analysis of infrared spectra revealed the stretching vibrations of tri and tetra borate and absence of boroxol ring in prepared composition. From UV-Vis absorption spectra, the values of optical band gap were found to lie between 1.48 and 2.84 eV for indirect allowed transitions, and for indirect forbidden transitions, values of optical band were lie between 1.01 to 2.62 eV. Urbach's energy lies between 0.23 to 0.61 eV.