Dense medium plasma synthesis of carbon/iron-based magnetic nanoparticle system

Using dense medium plasma technology, hybrid iron and iron oxide/carbon-based nanoparticle composites were synthesized under room temperature and atmospheric pressure conditions. Based on results from electron spectroscopy for chemical analysis, Fourier transform infrared spectroscopy, Raman microscopy, atomic force microscopy and scanning electron microscopy, we conclude that the material is composed of spherical particles, 40–60 nm in diameter, which are a graphitic carbon host structure embedded with iron and iron oxide. Thermal gravimetry/differential thermal gravimetry analysis indicates that these composites are stable up to temperatures as high as 600 °C. Ferromagnetic resonance spectroscopy (FMR) and extended x-ray absorption fine-structure spectroscopy suggest that the bulk of the FMR signal in question is due to metallic Fe. Magnetite or maghemite is present, and the metallic content of the metal particles is 58(8)% and the remainder is oxidized with a sixfold oxygen coordination shell similar to that of γ-Fe2O3.