Effect of different rare earth (RE = Y3+, Sm3+, La3+, and Yb3+) ions doped on the magnetic properties of Ni–Cu–Co ferrite nanomagnetic materials

With the development of science and technology, the research on magnetic materials is particularly important. In particular, the application of nanomagnetic materials in computer chips, magnetic recording, and biomedical fields has high research value. In this paper, Ni–Cu–Co ferrite nanomagnetic materials doped with rare earth (RE = Y3+, Sm3+, La3+ and Yb3+) ions were prepared by sol–gel auto-combustion method. The spinel structure of the sample was analyzed by X-ray diffraction (XRD), and the average crystallite size of the doped rare earth ions was calculated by the half width of (311) peak. The samples were further characterized by Fourier-transform infrared spectroscopy (FT-IR). Two characteristic peaks are at the wave number of 603 cm−1 and 391 cm−1, respectively. The morphology of the nanomagnetic grains was observed by scanning electron microscopy (SEM), and it was found that the nanomagnetic grains of the samples were all spherical or quasi spherical structure with water chestnut. Transmission electron microscopy (TEM) was used to observe the pure samples and Y3+ ion-doped samples. Through EDS analysis, it is found that the chemical composition of the sample is Ni, Cu, Co, Fe, O, Y, Sm, La, and Yb. Through vibration sample magnetometer (VSM) analysis, the samples of Ni–Cu–Co ferrite doped with different RE3+ ions have the characteristics of ferromagnetism.