Synthesis, Microstructure and Magnetic Properties of Nanocrystalline MgFe2O4 Particles: Effect of Mixture of Fuels and Sintering Temperature

Abstract

The present article reports the results of studies related to the synthesis of MgFe2O4 nanocomposite powder by solution combustion process using mixture of fuels containing urea (U) and ammonium acetate (AA). The effect of mixture of fuel and sintering temperature on phase formation, structural, morphological and magnetic properties of MgFe2O4 particles were investigated by X-ray diffraction (XRD), thermogravimetric analysis (TGA), Raman spectroscopy, scanning electron microscopy (SEM), energy dispersive absorption x-ray (EDAX) and vibrating sample magnetometer (VSM). Thermodynamic modeling of the combustion reaction shows that by using a mixture of urea and ammonium acetate fuels, the adiabatic flame temperature (Tad), exothermicity and amount of gases produced during the combustion process as well as product characteristics could be controlled. The use of mixture of fuels (U and AA) in the synthesis of MgFe2O4 was found to produce ferrites with finer agglomerates, higher crystallinity, higher magnetic properties and smaller crystallite sizes than when only urea was used. It was found that only samples prepared with a mixture of fuels (0.5U + 0.5AA) and sintered at 900o C for 2 h produced pure ferrite spinel phase while the auto-combusted and powders sintered at 600o C for 2 h had secondary phases. Apart from giving detailed information about the structural order of the samples, Raman spectroscopy also confirmed that MgFe2O4 is a mixed spinel ferrite