The synthesis of core-shell iron@gold nanoparticles and their characterization

Au-coated magnetic Fe nanoparticles have been successfully synthesized by partial replacement reaction in a polar aprotic solvent with about I I rim core of Fe and about 2.5 nm shell of An. In this work, a combination of TEM (transmission electron microscopy), XRD (X-ray powder diffractometry), EDS (energy disperse X-ray spectroscopy), SQUID (superconducting quantum interference device), TGA (thermograviometric analysis) and UV-visible absorption spectroscopy were employed to characterize the morphology, structure, composition and magnetic properties of the products. HRTEM images show clear core-shell structure with different crystal lattices from Fe and An. SQUID magnetometry reveals that particle magnetic properties are not significantly affected by the overlayer of a moderately thick An shell. The Au-coated particles exhibit a surface plasmon resonance peak that red-shifts from 520 to 680 nm. And all the above characterizations show that in this sample there are no iron oxides inside the particle.