Synthesis and intrinsic magnetic properties of interconnected carbon micro-sphere

Interconnected carbon micro-spheres (CMSs) with diameters in the range of 3 similar to 5 mu m were synthesized by acetylene pyrolysis at 750 degrees C on a SiO2 substrate. The CMSs have a graphitic structure with many intrinsic defects. Results indicate that the CMSs show both diamagnetic and paramagnetic behavior. Intrinsic defects have magnetic moments with spin 1/2. Approximately every 1,000 carbon atoms contribute 1.1 mu(B) unpaired spins. The unpaired spins have no interactions with each other and show typical Curie-like paramagnetic behavior.