Preparation and characterization of MgFe2O4 nanocrystallites via PVA sol-gel route

MgFe2O4 nanocrystallites were prepared by a polyvinyl alcohol (PVA) sol-gel route. Differential scanning calorimetry (DSC) and thermogravimetric (TG) analysis, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Raman spectroscopy and Environmental scanning electron microscope (ESEM) were used to characterize the precursors and the derived oxide powders. The effect of Mg/Fe molar ratio on the formation of MgFe2O4 were investigated. XRD analysis showed that single-phase MgFe2O4 was obtained from Mg/Fe = 0.55 and 0.6 precursor at a temperature of 500 °C for 2 h, without the formation of any intermediate phase. The crystallite size of MgFe2O4 with Mg/Fe = 0.55 calcined at 500 °C is ∼12 nm. For the Mg/Fe = 0.5 precursor, phase pure MgFe2O4 could not be obtained even at 800 °C, with α-Fe2O3 as impurity phase. The saturation magnetizations of the nanocrystalline MgFe2O4 (Mg/Fe = 0.55) calcined at 500 and 700 °C are 10.8 and 25.6 emu g−1, respectively.