Synthesis, structure, properties and magnetic applications of carbon-coated nanocrystals produced by a carbon arc

Out of the fullerene field has grown the exciting potential for synthesis of magnetic nanoparticles of both scientific and technical interest. We employ a Kratschmer-Huffman carbon are method to synthesize carbon-coated elemental transition metal and alloy particles with nanocrystalline dimensions. These have included FeCx, Co[C] and Ni[C] ferromagnetic particles. Recently, SmCox[C] particles with nanocrystalline dimensions have been produced by this method starting with a Sm2Co7 metallic precursor. Structural characterization by X-ray diffraction and high resolution transmission electron microscopy illustrate the phases present and the particle size distribution. Magnetic properties, as determined by superconducting quantum interference device magnetometry are also reported. These include hysteretic, temperature and time-dependent magnetic responses and an inferred superparamagnetic response. A unifying theme in this research is the carbon are synthesis of materials with interesting magnetic properties and assessment of their use in xerography, magnetic resonance imaging, ferrofluids, data storage and magnetic inks.