Fabrication of core-shell type FeCo-Au (Ag) high moment magnetic nanoparticles

We developed a physical vacuum deposition technique combining an on-line sputtering/evaporation process with an integrated nanocluster deposition process to prepare core-shell type nanoparticles, High magnetic moment (Fe ₆₀Co₄₀)_CoreAu_Shell and (Fe ₆₀Co₄₀)_CoreAg_Shell superparamagnetic nanoparticles with controllable particle size of 10 - 20 nm and Au/Ag shell thickness of 1 - 3 nm were prepared successfully by using this method. Au shell is not only functional for the potential biocompatibility but also the key to prevent the oxidation of FeCo nanoparticles. Saturation magnetization of (Fe₆₀Co₄₀)_CoreAu_Shell nanoparticles was found three times higher than that of iron oxide nanoparticles. This novel technique enables us to control independently the dimensions of core and shell and select individually materials for core and shell for any other core-shell type nanoparticles.