Effect of sintering temperature on magnetization and Mossbauer parameters of cobalt ferrite nanoparticles

Nanoparticles of cobalt ferrite of different particle size were prepared using sol-gel method. Powder X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM) and Mossbauer spectroscopy techniques were employed for characterization of nanoparticles for structural and magnetic properties. The particle size and saturation magnetization increase with the increase of sintering temperature. The saturation magnetization increases from 53 to 85 emu/g as the sintering temperature increases from 300 to 900 degrees C. The remanence increases while the coercivity decreases slightly with the increase of sintering temperature. Mossbauer spectra show the ferrimagnetic nature of all the samples and the cation distribution strictly depends on the sintering temperature. The stoichiometry of the cobalt ferrite formed was estimated to be (Cox2+Fe1-x3+)[Co1-x2+Fe1+x3+]O-4, based on our Mossbauer analysis. The inverse spinel structure gradually transforms towards the normal spinel structure as the sintering temperature increases.