Synthesis and magnetic properties of Fe sub(3)C-C core-shell nanoparticles

Fe sub(3)C-C core-shell nanoparticles were fabricated on a large scale by metal-organic chemical vapor deposition at 700 [degrees]C with ferric acetylacetonate as the precursor. Analysis results of x-ray diffraction, transmission electron microscope and Raman spectroscope showed that the Fe sub(3)C cores with an average diameter of ~35 nm were capsulated by the graphite-like C layers with the thickness of 2-5 nm. The comparative experiments revealed that considerable Fe sub(3)O sub(4)-Fe sub(3)C core-shell nanoparticles and C nanotubes were generated simultaneously at 600 and 800 [degrees]C, respectively. A formation mechanism was proposed for the as-synthesized core-shell nanostructures, based on the temperature-dependent catalytic activity of Fe sub(3)C nanoclusters and the coalescence process of Fe sub(3)C-C nanoclusters. The Fe sub(3)C-C core-shell nanoparticles exhibited a saturation magnetization of 23.6 emu g super(-1) and a coercivity of 550 Oe at room temperature.