Effect of co-doping with Mg²⁺ and Ce³⁺ on the enhanced electrical and magnetic characteristics of cobalt nano ferrites

The sol–gel auto-combustion process synthesized materials with Mg²⁺ and Ce³⁺-substituted CoFe₂O₄ nano ferrites. The research focuses on the nanoparticles, specifically Co_1−xMg_xFe_2−yCe_yO₄ (where x = 0.0, 0.25, 0.5, and 0.75; y = 0.0, 0.03, 0.06, and 0.09) (CMC) ferrite nanomaterials characterizations utilizing techniques such as XRD, FESEM with EDS, FTIR, electrical analysis, and VSM. The X-ray powder diffraction (XRD) patterns indicate the formation of a spinel structure, with no distinct peaks for rare earth ions, likely due to their minimal doping. Increasing the ionic sizes of RE³⁺ ions decreases the lattice parameter of the resulting nanoferrites. Field emission scanning electron microscopy (FESEM) shows the samples are aggregated and nearly spherical. At the same time, energy-dispersive X-ray spectroscopy (EDS) confirms the presence of Co, Mg, Ce, Fe, and O. Fourier-transform infrared spectroscopy (FTIR) absorption bands predict the range of spinel ferrites, indicating that RE³⁺ ions replace Fe³⁺ ions in the B sites. DC electrical resistivity decreases with the concentration of substituted ions. Dielectric properties, including the dielectric constant, dielectric loss, and AC conductivity, were studied using LCR meters across various frequencies. AC conductivity increases with frequency while both the dielectric constant and loss decrease. These observations align with the Maxwell–Wagner polarization theory. The magnetic properties of CMC nanoparticles, such as squareness ratio (SQR = Mr/Ms), coercivity, saturation magnetization, remanence, and magnetic moment, were determined and analyzed using the vibrating sample magnetometer (VSM).