Characterization of oxidation resistant Fe@M (M=Cr, Ni) core@shell nanoparticles prepared by a modified reverse micelle reaction

Iron-based nanoparticles are the forerunners in the field of nanotechnology due to their high magnetization saturation and biocompability which affords them use in a variety of applications. However, iron-based nanoparticles, due to a high surface-to-volume ratio, suffer from oxidation and limit its practicality by lowering the magnetic moment significantly. To avoid this oxidation, the surfaces of the particles have to be passivated. One such way to accomplish this passivation is to synthesize core@shell nanoparticles that have a surface treatment of chromium or nickel. These core@shell nanoparticles have been synthesized using a reverse micelle technique. The Cr and Ni passivated iron nanoparticles were characterized by x-ray diffraction, transmission electron microscopy, vibrating sample magnetometry, and x-ray photoelectron spectroscopy to determine their phase, morphology, surface properties, and magnetization saturation. A high magnetization saturation of 160 and 165 emu/g for Cr and Ni passivated iron core@shell nanoparticles was achieved. (C) 2011 American Institute of Physics. [doi:10.1063/1.3548828]