Characterization of magnetic properties and microstructures for Co²⁺ ions-doped Ni–Cu–Zn ferrites

Abstract

In this study, novel Ni–Cu–Zn ferrites with the chemical formula [Ni_0.6Zn_0.4][Cu_0.2Co_xFe_1.8−x]O₄ (x = 0, 0.05, 0.10, 0.15, 0.20, 0.25) doped with Co²⁺ ions were designed and manufactured by standard solid-state reaction method. The magnetic properties, surface characteristics, and ion occupancy of ferrites were studied by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometer (VSM), and we explained the different mechanisms of the results and the relationship between magnetic properties and microstructures. For the obtained samples, cobalt ions entered the lattice, and all samples were characterized as spinel structures. As the do** amount of Co²⁺ ions increases, the lattice constant and volume of the sample also increases. With an appropriate do** level, Co²⁺ ions-doped Ni–Cu–Zn ferrites can maintain higher saturation magnetization, higher magnetic permeability, and lower hysteresis loss. When x ≤ 0.1, the saturation magnetization M_s increases significantly as the do** amount of Co²⁺ ions increases, but when x > 0.1, the value decreases. The experimental results show that the saturation magnetization value is 118.08 emu/g, the magnetic permeability value is 39.47 H/m, and the hysteresis loss is 1.192 mW/cm³ at an optimum do** amount. Therefore, the sample achieves the best magnetic properties when the do** amount is 0.1.