Mössbauer and electrical investigation of sulfur-doped sodium borate glasses containing iron

Abstract

Three series of sulfur-doped sodium tetraborate glasses containingiron was prepared with the composition (Na₂ B₄ O₇ ) _1–x (Fe₂ O ₃ ) x , wherex equals 0.1, 0.2 and 0.3. One series of the glass was left free of sulfur,while sulfur was added to the other two series of 2.5 and 5 wt%, respectively,to investigate the role of sulfur ions on some physical properties of thistype of glass. Melting process was carried out in platinum crucibles at 1100°C for one hour. The glasses were quenched in air at room temperature.X-ray diffraction measurement was carried out to be sure that the pure glassystate is obtained. ⁵⁷Fe Mössbauer spectroscopy and dc conductivitymeasurements were carried out. It was found that iron is present in form ofFe²⁺ and Fe ³⁺ ions. Sulfur ions increased the valuesof dc conductivity. The isomer shift of the two states of iron is stable whilethe quadrupole splitting value changed with increasing Fe₂ O₃ content or as sulfur was added.