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

Room temperature electron paramagnetic resonance (EPR) and temperature dependent magnetic susceptibility studies have been performed on 4.5MgO center dot(45-x)CaO center dot 34SiO(2)center dot 16P(2)O(5)0.5CaF(2 center dot)xFe(2)O(3)(55 <= 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 approximate to 4.3 and g approximate to 2.1, with their relative prevalence depending on the Fe(2)O(3) 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 Fe(2)O(3) 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.