Microstructure, XPS and magnetic analysis of Al-doped nickel–manganese–cobalt ferrite

X-ray diffraction, X-ray electron spectroscopy and magnetic measurement techniques were used to study the structure and magnetic properties of ferrites. The sample was prepared by the sol–gel method under the conditions of different doses of drugs, and then annealed at 900 °C to improve the microstructure of the sample. For spinel ferrite, cations on its microstructure are replaced to improve magnetic properties. Doping with non-magnetic Al3+ ions to study the change of the properties of the sample by the zero magnetic moment ions. Al3+ ion doping has an effect on the microstructure and magnetic properties of the sample. The doped sample still has a pure phase structure without forming an impurity phase, which confirms the purity of the sample. The shape of the hysteresis loops of all samples indicates that they are hard magnetic. This above all proves that Al3+ ions enter the crystal lattice because it is smaller than the particle radius of Fe3+ ions.