Influence of the Mg-content on the cation distribution in cubic MgxFe3−xO4 nanoparticles

The influence of the Mg-content on the structural and magnetic properties of cubic MgxFe3−xO4 nanoparticles prepared by combustion reaction was investigated using X-ray diffraction, transmission electron microscopy (TEM), Mössbauer spectroscopy, and Raman spectroscopy. Lattice parameter, nanoparticle size, and cation (Mg2+, Fe3+) distribution were quantified as a function of the Mg-content in the range 0.5≤x≤1.5. We found a mixed-like spinel structure at the smaller x-value end whereas the inverse-like spinel structure dominates samples with larger x-values. Moreover, in the x-value range investigated (0.5≤x≤1.5) we found no change in the quadrupole splitting and isomer shift values, though the hyperfine field decreases as the x-value increases. The splitting of the A1g Raman mode was used to both quantify the Mg2+/Fe3+ contents in the tetrahedral site and obtain the cation distribution in the MgxFe3−xO4 structure. The cation distribution obtained from the Raman data is in very good agreement with the cation distribution obtained from the Mössbauer data.

Raman spectra of MgxFe3−xO4 samples (x=0.5, 1.0, and 1.5) using the Ar+ 514.5 nm laser line.Figure optionsDownload as PowerPoint slide