Facile approach for synthesis of high moment Fe/ferrite and FeCo/ferrite core/shell nanostructures

In the present study, we developed a facile approach for synthesis of high magnetic moment monodisperse Fe/ferrite and FeCo/ferrite core/shell nanoparticles. Fe₃O₄ and CoFe₂O₄ nanoparticles were at first synthesized through sonochemical process, followed by thermal annealing in presence of hydrogen (H₂) gas for 2 h for reduction into Fe and FeCo nanoparticles, respectively. Then, oxidation of Fe and FeCo nanoparticles up to 48 h in air atmosphere resulted in complete formation of Fe/ferrite and FeCo/ferrite core/shell nanostructures. Different analytical techniques such as X-ray diffraction, transmission electron microscopy, energy dispersive spectroscopy and vibrating sample magnetometer were used to characterize and confirm the successful formation of the core/shell nanostructures. In view of the obtained high magnetic Fe or FeCo core and biocompatible ferrite shell, these core-shell Fe/ferrite and FeCo/ferrite nanoparticles are expected to be promising materials for various bio-sensing applications.