| Abstract
| - We report the chemical synthesis of Fe-core/Au-shell nanoparticles by a reverse micelle method andthe investigation of their growth mechanisms and oxidation-resistant characteristics. The core−shellstructure and the presence of the Fe and Au phases have been confirmed by transmission electronmicroscopy, energy dispersive spectroscopy, X-ray diffraction, Mössbauer spectroscopy, and inductivelycoupled plasma techniques. Additionally, atomic-resolution Z-contrast imaging and electron energy lossspectroscopy (EELS) in a scanning transmission electron microscope (STEM) have been used to studydetails of the growth processes. The Au shell grows by nucleating on the Fe-core surface before coalescing.The magnetic moments of such nanoparticles, in the loose powder form, decrease over time due tooxidation. The less than ideal oxidation resistance of the Au shell may have been caused by the roughAu surfaces. However, in pressed pellet form, electrical transport measurements show that the particlesare fairly stable, as the resistance of the pellet does not change appreciably over time.
- Core/shell structured Fe/Au nanoparticles have been realized, and the presence of the elemental phases has been confirmed. The Au shell appears to grow by nucleation at selected sites on the Fe core surface before coalescing. The rough surface could compromise the oxidation resistance of the Au shell.
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