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 synthe sis of magnetic nanoparticles of both scientific and technical interes t. We employ a Kratschmer-Huffman carbon are method to synthesize carb on-coated elemental transition metal and alloy particles with nanocrys talline dimensions. These have included FeCx, Co[C] and Ni[C] ferromag netic particles. Recently, SmCox[C] particles with nanocrystalline dim ensions have been produced by this method starting with a Sm2Co(7) met allic 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 d etermined by superconducting quantum interference device magnetometry are also reported. These include hysteretic, temperature and time-depe ndent magnetic responses and an inferred superparamagnetic response. A unifying theme in this research is the carbon are synthesis of materi als with interesting magnetic properties and assessment of their use i n xerography, magnetic resonance imaging, ferrofluids, data storage an d magnetic inks.