Characterization and magnetic property of carbon coated metal nanoparticles and hollow carbon onions fabricated by CVD of methane

摘要

This work focuses on the structural characterization and magnetic property of carbon onions, which were synthesized via catalytic decomposition of methane over Ni/AI catalyst. The results showed that the small microcrystalline planar is 3.2 nm for the obtained carbon onions according to calculation from Raman. The saturation magnetization at room temperature of the carbon onions is 27.12 emu/g, which is 53% of the bulk ferromagnetic element counterpart due to the inclusive phases of carbon and magnetic effect of small particles with larger surface to volume ratio. The coercive force at room temperature of the carbon onions is 141.6 Oe, while the ratio of remnant to saturation magnetization M_r/M_s is about 0.247.