Structural and magnetic properties of nano-NiFe2O4 prepared using green nanotechnology

Nanocrystalline spinel ferrite NiFe2O4 powders were synthesized by a novel green nanotechnology derivative of sol–gel method. The effect of preparation conditions on the particle size (D) and accordingly magnetic properties was investigated using X-ray powder diffraction (XRD), Mössbauer effect spectrometer (ME) and vibrating sample magnetometer (VSM). The obtained results were compared to samples prepared using a standard ceramic method and a sol–gel technique using a citric acid route. XRD measurements reflected the spinel structure of prepared samples. The results confirmed the critical dependence of the particle size on the preparation method and heat treatment. Mössbauer effect spectroscopy measurements indicated a strong impact of the particle size on the measured spectra. A gradual decrease of the hyperfine field with decreasing D was observed. Both the saturation magnetization MS and the coercivity Hc are found to be influenced by the decrease of the particle size.