PREPARATION AND PROPERTIES OF CARBON-COATED MAGNETIC NANOCRYSTALLITES

Carbon-coated gadolinium carbide nanocrystallites are generated by a process based on the Kratschmer-Huffman carbon-arc method of preparing fullerenes, and a novel magnetic-field-gradient separation technique is used to separate them. This separation of nanocrystalline byproducts of the carbon arc process is a prerequisite for many of the proposed applications of these materials. While the data presented pertain to Gd2C3, this method is generally applicable to any paramagnetic or ferromagnetic compound. Structural characterization by x-ray and electron diffraction and high-resolution transmission electron microscopy reveal the presence of a single gadolinium-containing (Gd2C3) phase and excess carbon. The carbide phase exists as 10-50 nm spherical particles. SQUID magnetometry shows paramagnetic response attributed to Gd3+ ions.