Influence of Mg2+ replacement on the structure and magnetic properties of MgxZn1−xFe2O4 (x = 0.1–0.5) ferrites

In this study, the Mg–Zn polycrystalline ferrites with the chemical formula MgxZn1−xFe2O4 (x = 0.1, 0.2, 0.3, 0.4, 0.5) were prepared by standard solid-phase reaction method at the optimal sintering temperature of 1573 K. The structure and magnetic properties of ferrites were characterized by advanced technologies such as XRD, SEM, EDX, FTIR, XPS, and SQUID-VSM. The XRD and FTIR spectra confirmed that all samples had a spinel structure, and the lattice constant and volume decreased gradually. The SEM, EDX, and XPS spectra were used to characterize the microstructure, ion concentration and element valence of the sample. For the obtained sample, as the amount of Mg2+ ions doping increases, the competition between antiferromagnetic (AFM) and ferromagnetic (FM) causes the transition temperature to increase from 19 to 383 K, making it have a broader application prospect. Under the proper doping amount, the saturation magnetization (MS) and coercivity (HC) of all samples were ameliorated at ultra-low temperature and normal temperature. Experimental results show, with the continuous doping of Mg2+ ions, the values of MS and HC continue to increase, the maximum value of Ms can reach 43.6 emu/g (at 300 K) and 96.8 emu/g (at 5 K), and the maximum value of Hc can reach 38.5 Oe (at 300 K) and 99.6 Oe (at 5 K) in the series, which has just reached the use requirements of inductors, transformers and other magnetic components.