Effect of Ni substitution on structural, optical and magnetic properties of ferrite nanoparticles synthesized by co-precipitation route

In this research, fine nanoparticles of NixFe3-xO4 with Ni concentration up to x = 1.5 were synthesized via a simple one-step capping agent-free co-precipitation route. The effect of Ni substitution was investigated by details using X-ray diffractometer, transmission electron microscope, Fourier transform infrared and UV-Vis spectroscope, and vibrating sample magnetometer. The structural studies revealed that the particles have good crystallinity with diameters of 7.5-13 nm with cubic spinel structure. The FTIR spectra exhibiting a doublet band around 600 cm(-1) confirms further the mixed spinel structure. It was found that the involved nanoparticles are indirect band gap materials that controlled by the size effect rather than the influence of the chemical composition. The magnetic characterization showed that the nanoparticles are superparamagnetic at room temperature with the superior saturation magnetizations of about 68-70.5 emu/g; the size effects dominate the influence of the sites occupancy in controlling the magnetization values, as well.