Superparamagnetic cobalt ferrite nanoparticles synthesized by gamma irradiation

Abstract

The radiolytic method is used to synthesize ultrasmall cobalt ferrite nanoparticles, CoFe2O4, exhibiting superparamagnetic properties. These systems are investigated by studying their properties at increasing dose of the irradiation process. These magnetic nanoparticles (MNPs) are characterized by X-ray diffraction (XRD), high-resolution transmission electronic microscopy (HRTEM), energy dispersive spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). The XRD analysis and HRTEM observations confirm the formation of ultra-small cobalt ferrite nanoparticles (NPs) of CoFe2O4 (6-9 nm) in the cubic spinel structure. The temperature-dependent magnetic measurements reveal that the NPs exhibit superparamagnetic properties with a high magnetization Ms ∼ 70 Am2 kg−1 at 300 K and a very low coercivity (0.9 mT).