Structural studies on iron–tellurite glasses prepared by sol–gel method

In this study, we report structural properties of the iron–tellurite glasses obtained using the sol–gel synthesis. The samples were characterized by X-ray diffraction, FTIR, UV–vis and EPR spectroscopy. Our results indicate dominant presence of iron ions in the trivalent state and the existence some Fe2+ ions. The analysis of the IR spectra indicates a gradual transformation of iron ions from tetrahedral into octahedral sites when the concentration of Fe(NO3)3 is increased beyond 0.64 mol%. EPR studies show that the increase of Fe(NO3)3 content in the host matrix induces the growth of the number of effective g values. This can be explained considering that the orbitals of O2− ion with a large spin–orbit interaction constant will interact with the 3d orbital of Fe3+ ion bonded to this O2− ion, thus leading to appearance of an orbital angular momentum which contributes to the magnetic moment of Fe3+ ion. A strong dipolar interaction, which is more predominant in a glass with higher content of Fe(NO3)3, causing a localized magnetic field along the site of the Fe3+ ions and the increase the effective g values.

Research highlights▶ Iron–tellurite glasses obtained using the sol–gel synthesis.