Copper Substitution and Sintering Temperature Effects on the Structural and Magnetic Properties of Nizn Ferrite Particles

This study investigates the structural and magnetic properties of Ni₀.₆₋ₓZn₀.₄CuₓFe₂O₄ ferrite particles (x = 0–0.5, in increments of 0.1) synthesized via the sol–gel method. The effects of heat treatment temperature and copper additive content on the structural and magnetic characteristics of the ferrite powders were examined. The powder samples were subjected to prolonged heat treatment (13 hours) at 800 °C, 900 °C, and 1000 °C, and the Curie temperature was measured for compositions of x = 0 and x = 0.5, showing a decrease from approximately 580 °C for the Cu free sample to about 470 °C for the Cu substituted sample. X ray diffraction (XRD) and energy dispersive spectroscopy (EDS) analyses confirmed the formation of the NiCuZn spinel structure, with the lattice parameter increasing from about 8.29 Å (x = 0) to 8.42 Å (x = 0.5). Field emission scanning electron microscopy (FE SEM) micrographs demonstrated that increasing copper content and heat treatment temperature enhances particle growth. Hysteresis loop measurements revealed ferrimagnetic behavior in all samples; the saturation magnetization increased with Cu substitution and reached a maximum value of about 83 emu/g at x = 0.3, then decreased to approximately 49 emu/g at x = 0.5, while the coercivity varied in the range of about 48–122 Oe. These findings contribute to the understanding of how Cu incorporation influences the microstructure and magnetic properties of NiZn ferrites, which is essential for their potential applications in electronic and magnetic devices.