Structure And Magnetic Properties Of Magnetic Iron Oxide/Zinc Oxide Core/Shell Nanocomposites: Effect Of Zno Coating

This paper presents a comprehensive view of effect of ZnO coating on structure and magnetic properties of the magnetic iron oxide/ZnO core/shell nanocomposites. The nanocomposites with Fe:Zn molar ratio of 7:1, 5:1 and 3:1 were synthesized by using two-step co-precipitation method. Crystal structure, microstructure, composition, valence state, morphology and magnetic properties of the samples were systematically investigated by using synchrotron X-ray diffraction, X-ray absorption near-edge spectroscopy, Fourier transform infrared spectra, field emission scanning electron microscope, transmission electron microscopy and vibrating sample magnetometer. The obtained results indicated that the nanocomposites exhibit superparamagnetic behavior at room temperature. Structure and magnetic properties of the nanocomposites are strongly influenced by ZnO content as microstrain increases, magnetization and blocking temperature decrease upon ZnO coating. The change in magnetic properties of the nanocomposites has been discussed based on detailed information on composition and structure, spin canting and surface effect.