Study on structure and magnetic properties of Ni–Co co-substituted ZnFe 2 O 4 prepared by sol–gel method

At room temperature, Ni x Zn 1-x-y Co y Fe 2 O 4 ( x = 0.0 y = 0.0, x = 0.8 y = 0.0, x = 1.0 y = 0.0, x = 0.0 y = 0.8, x = 0.0 y = 1.0, x = 0.4 y = 0.4) were synthesized using the sol–gel method. Using pure nickel, zinc and cobalt ferrite as control group, and the structure and properties of ferrites containing two substituents were analyzed by each characterization. According to the X-ray diffraction (XRD) results, the prepared samples have spinel structures and no other impurity phases. Fourier transform infrared (FT-IR) spectroscopy examines the completeness and functional group information of the preparation procedure, and the samples’ spinel structures were once again confirmed. Using a UV–Vis absorption spectrum examines the samples’ band-gap value, and verifies their semiconductor properties. According to the scanning electron microscope (SEM), the sample agglomerates because of its magnetism, and forms a spherical cube. Besides, the narrow particle-size distribution shows a homogeneous sample size. Energy-dispersive spectroscopy (EDS) analyzes the sample which does not contain other impurity elements, and the element composition was consistent with the chemical formula of the prepared sample. A vibrating sample magnetometer (VSM) was used to examine the magnetic characteristics of the different samples. The superparamagnetism of zinc ferrite, ferromagnetism of cobalt ferrite, and sub-ferromagnetism of nickel ferrite could be obtained from the hysteresis loop diagram.