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

This work reports on room-temperature ferromagnetism of pyrolytic oxidized-graphene nanoplatelets obtained from bamboo pyroligneous acid by varying the density of extended defects. 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 magnetic force microscopy measurements. Increased defect density, tuned by carbonization temperature, results in enhanced magnetization.