Room-temperature ferromagnetism in oxidized-graphenic nanoplatelets induced by topographic defects*

Pyrolytic oxidized-graphenic nanoplatelets (OGNP) obtained from bamboo pyroligneous acid (BPA) by varying the density of extended defects, show room-temperature ferromagnetism. Topographic defects, created during the fabrication process, arise from a natural formation of clusters; such clusters drastically distort the graphitic basal plane, giving rise to abrupt surface curvatures. Topographic defects were found to be sources of the magnetic signal, as evidenced by bulk magnetization and MFM measurements. Increased defect density, which is tuned by carbonization temperature, results in enhanced magnetization.