EPR and magnetic properties of MgO–CaO–SiO2–P2O5–CaF2–Fe2O3 glass-ceramics

Glass-ceramics have been derived from 4.5MgO(45−x)CaO34SiO216P2O50.5CaF2xFe2O3 (x=5, 10, 15, 20 wt%) glasses by heat treatment. Room temperature electron paramagnetic resonance (EPR) spectra and temperature-dependent magnetic susceptibility (χ) of the glass-ceramics have been obtained. The EPR absorption line centered at g≈4.3 disappeared at higher concentrations of iron oxide. The intensity and line width of the EPR absorption line centered at g≈2.1 increased as the iron oxide concentration was increased. Temperature-dependent magnetization of samples with low iron oxide content revealed ferrimagnetic as well as paramagnetic contributions. Information about the structural changes involving iron ions, their valence state and the type of magnetic interactions between the Fe ions as a function of composition was obtained using EPR and χ studies.