Investigation of MoS₂ and graphene nanosheets by magnetic force microscopy

For the first time, magnetic force microscopy (MFM) is used to characterize the mechanically exfoliated single- and few-layer MoS₂ and graphene nanosheets. By analysis of the phase and amplitude shifts, the magnetic response of MoS₂ and graphene nanosheets exhibits the dependence on their layer number. However, the solution-processed single-layer MoS₂ nanosheet shows the reverse magnetic signal to the mechanically exfoliated one, and the graphene oxide nanosheet has not shown any detectable magnetic signal. Importantly, graphene and MoS₂ flakes become nonmagnetic when they exceed a certain thickness.