Characterization of magnetic nanoparticles synthesized by sonomechanical method

We have synthesized magnetic nanoparticles using the newly developed sonomechanical method with the FeSO₄´7H₂O and characterized crystallographic structural changes, surface morphology, chemical bonding states and magnetic properties. The crystallographic structure of the nanoparticles was characterized with high resolution X-ray powder diffraction (XRD) analysis. The surface morphology of the nanoparticles was observed by scanning electron microscopy. The chemical bonding states of Fe ions in the nanoparticles were examined by X-ray photoelectron spectroscopy (XPS) analysis. The magnetic properties of the nanoparticles were analyzed with vibrating sample magnetometer at room temperature. The XRD patterns and XPS spectra indicated that the synthesized nanoparticles were mixture of magnetite (Fe₃O₄) and maghemite (gamma-Fe₂O₃). As varying post annealing temperature, it seems that there was occurred transition to magnetite to maghemite and maghemite to magnetite.