Analysis on the cation distribution of Mg_xNi_1−xFe₂O₄ (x = 0, 0.25, 0.5, 0.75, 1) using Mössbauer spectroscopy and magnetic measurement

Mg_xNi_1−xFe₂O₄ (x = 0, 0.25, 0.5, 0.75, 1) spinel ferrite material was analyzed to determine its magnetic properties and structure. X-ray diffraction (XRD), Mössbauer spectroscopy, and vibrating sample magnetometer (VSM) characterization were performed on the samples prepared using the sol–gel method. The results from XRD confirmed the existence of the single-phase cubic spinel structures $Fd\overline{3}m$, as well as the evolution of the crystalline size (D), the lattice parameter (a) and cell volume in compounds. The Mössbauer spectra showed the distribution of cations and changes in the magnetic properties of the sample. VSM measurement revealed that the samples were room-temperature ferromagnetic. Moreover, the saturation magnetization (M_s) of the samples changed with the Mg²⁺ ion content x, and a maximum occured at x = 0.5. Doping with Mg²⁺ ions increased the transfer of Ni²⁺ ions to tetrahedral sites, thus increasing the magnetic moment difference between tetrahedral (A) and octahedral (B) sites. Specifically, doping NiFe₂O₄ with Mg²⁺ ions can enhance its magnetic properties and enhance its saturation magnetization.