Ferromagnetic amorphous carbon derived from low molecular weight organic compounds

摘要

Recently ferromagnetic signals have been observed in host of carbonaceous materials. In this paper, we report that the simple combustion products of low-molecular weight aromatic compounds like toluene and naphthalene clearly show ferromagnetic signals at 300 and 10 K with coercivity as low as ≈-70 Oe and -100 Oe at 300 K and 10 K respectively and saturation magnetization as high as 5.1 × 10~(-4) and 5.5 × 10~(-4) emu at 300 K for toluene and naphthalene carbon respectively. These materials have been found to be air-stable at room temperature and they do not strictly obey Curie-Weiss law. The combustion products were characterized with the aid of Magnetometric studies, FTIR, SEM and TEM. Atomic absorption spectrophotometric analysis reveals that among ferro/ferrimagnetic contaminants, only iron is present in such a low concentration that it cannot account for a saturation magnetization as high as 5.5 × 10~(-4) emu. Hence, the origin of ferromagnetism is partly intrinsic in nature.