Structural and magnetic properties of MgO-CaO-SiO2-P2O5-CaF2-Fe2O3 glasses

摘要

Room temperature electron paramagnetic resonance (EPR) and temperature dependent magnetic susceptibility studies have been performed on 4.5MgO.(45-x)CaO.34SiO2.16P2O50.5CaF2.xFe2O3 (5≤x≤20 wt%) glasses. The EPR spectra of the glasses due to Fe~(3+) (3d~(5.6),S_(1/2)) paramagnetic ions mainly consisted of resonance absorption lines centred at g≈4.3 and g≈2.1, with their relative prevalence depending on the Fe2O3 content in the respective glass composition. The variation of the intensity and line width of these absorption lines in the EPR spectra of the glasses as a function of Fe2O3 concentration has been interpreted in terms of variations in the concentration and interaction of Fe~(2+) and Fe~(3+) ions in the glasses. EPR and magnetic susceptibility data of the glasses reveal that both Fe~(3+) and Fe~(2+) ions are present in glass matrix, with their relative concentration strongly dependent on the glass composition. Superexchange type interaction was detected which strongly depended on the iron content in the glass samples.