Magnetic properties of carbon nano-particles produced by a pulsed arc submerged in ethanol

Carbon powder was produced by a pulsed arc ignited between two carbon electrodes submerged in ethanol, and was comprised of both micro- and nano-particles. The measured magnetic properties of the mixed “raw” powder at 20 and 300 K were: saturation magnetization Ms ∼ 0.90-0.93 emu/g, residual magnetization Mr = 0.022 and 0.018 emu/g, and coercive force Hc = 11 and 8 Oe, respectively. The data lead to conclusion that the powder consisted of ferromagnetic particles with a critical temperature much higher than 300 K. Magnetic particles in solution were separated by means of bio-ferrography. It was found that the magnetically separated particles included chains of ∼30-50 nm diameter spheres, and nanotubes and nanorods with lengths of 50-250 nm and diameters of 20-30 nm. In contrast, the residual particles which passed through the bio-ferrograph consisted of 1 μm and larger micro-particles, and nano-particles without any definite shape.