Microstructures and magnetic properties of NiCuZn ferrite ceramics doped with MnO₂–Bi₂O₃

In this study, Ni_0.4−xMn_xCu_0.3Zn_0.3Fe_1.98O₄ ferrites were fabricated using a solid-state reaction method. The microstructures and magnetic properties of the samples were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), impedance spectroscopy, and conductivity tests. The XRD patterns showed the ferrite structures of the samples. According to the SEM images, an appropriate increase in the Mn²⁺ content yields large grains and lattice distortions on the sample surface. The dielectric constants and magnetic properties of the ferrites at room temperature were also investigated. The addition of 1.5-wt% Bi₂O₃ to the samples reduced the sintering temperatures of the ferrites, which effectively promoted the growth and enhanced the density of the grains. The replacement of Ni²⁺ by Mn²⁺ affected the microstructure, permeability, saturation magnetization, and dielectric constant of the ferrite sample.