Effects of sintering process on the structural, magnetic and thermal properties of Ni0.92Ca0.08Fe2O4 nanoferrite

Nanoparticles of Ni0.92Ca0.08Fe2O4 ferrite was prepared by the citrate precursor method. The effect of sintering temperature and sintering time on the structural, magnetic, and thermal properties of the prepared samples were investigated by using x-ray diffraction (XRD) and transmission electron microscope (TEM), vibrating sample magnetometer (VSM), and photoacoustic (PA) technique, respectively. The grain size of the sintered samples estimated from the XRD and the TEM results inform that the increase in the particle size is more announced by increasing the sintering temperature than increasing the sintering time. The unexpected decrease of the saturation magnetization of the sintered samples is ascribed to the dominant effect of the cation distribution which is affected by the sintering process. The cation distribution of the present samples was obtained from the analysis of the magnetization measurements and XRD data. The increase of measured density and the decrease of porosity of the sintered samples as a result of the grain growth have the obvious effect of increasing their thermal diffusivity.