The microstructure and magnetic behavior of spark plasma sintered iron/nickel zinc ferrite nanocomposite synthesized by the complex sol-gel method

In this study, a 2.7 wt% (Fe)/97.3 wt% (Zn0.3Ni0.7Fe2O4) nanocomposite (45-100 nm) was synthesized uisng the non-alkoxide complex sol-gel method by controlling the amount of Triethanolamine (TEA) and the annealing temperature. Various instuments including the simultaneous thermal analyzer (STA), Fourier transform infrared spectrometer, X-ray diffraction, scanning electron microscope equipped with X-ray dispersive spectroscopy, and vibrating sample magnetometer were used to characterize the samples. The STA results showed that the gel was converted from the amorphous phase to a crystalline one at 750 degrees C. The XRD pattern at the temperature of 750 degrees C also confirmed the presence of a spinel ferrite structure, alpha-Fe2O3 and Fe phases. By increasing the annealing temperature to 1100 degrees C, alpha-Fe2O3 as an impurity phase was eliminated, but the iron phase (formed through the reduction of the partial Fe3+ ions by TEA molecules as a sacrificial reducing agent) was still present. According to the VSM analysis of the SPSed sample, the exchange coupling between the iron phase and nickel zinc ferrite nanoparticles significantly improved the saturation magnetization of the spinel ferrite from 66.0 emu/g to 82.9 emu/g.