X-ray diffraction, magnetic measurements and Mössbauer spectroscopy of MgFe2O4 nanoparticles

Magnesium ferrite (MgFe2O4) was synthesized using the solution combustion method. The concentration of the fuel was varied and investigated its effect on spectroscopic, structural and magnetic properties of MgFe2O4 nanoparticles. The XRD pattern showed a decrease in the crystallite size and increase in the lattice strain, dislocation density and specific surface area upon increasing the fuel amount. The shift in the FTIR band (~434 cm–1) corresponds to the Fe–O vibration in the octahedral sites. The values of HC decreased while Mr values increased continuously with the increase of the fuel concentration. The Mössbauer spectra of MgFe2O4 nanoparticles measured with a high velocity resolution demonstrated a large number of magnetic sextets assigned to the tetrahedral (A) and octahedral [B] sites. These magnetic sextets were considered as a result of different Fe3+ local microenvironments depending on Mg2+ cations distributions among the neighboring (A) and [B] sites. The calculations of binomial distribution of the probabilities of the numbers of Mg2+ cations within the sphere of 3.7 Å around Fe3+ cations in both (A) and [B] sites demonstrated distributions of different probabilities for these sites in agreement with the Mössbauer spectra fits. The numbers of magnetic sextets and their hyperfine parameters assigned to the (A) and [B] sites were found slightly varied for MgFe2O4 nanoparticles prepared with different fuel concentrations.