Mossbauer, infrared and magnetic susceptibility studies of iron sodium borate glasses doped by sulphur

The affect of sulphur on the structural properties of iron sodium diborate glasses having the composition {(100−x)Na2B4O7+xFe2O3}+yS, where x=0.05, 0.15 and 0.25 mol% and Y=0, 2.5 and 5 wt% was studied by infrared, Mossbauer spectroscopy and magnetic susceptibility measurements. It was found that, for samples having 5 mol% Fe2O3 and free from sulphur, the iron ions are present in both Fe2+ and Fe3+ states and also 92% of the total iron enters the glass network as a glass former. The ratio of Fe3+/Fe2+ increases with increasing the iron content for sulphur-free samples and others containing sulphur. This ratio also decreases with increasing the sulphur content. The magnetic susceptibility was found to decrease with increasing the sulphur content. Also, the increase of Fe2O3 content led to a less symmetrical environment of Fe3+ ions and vice versa for the Fe2+ environment.