Microwave Energy Drives “On–Off–On” Spin‐Switch Behavior in Nitrogen‐Doped Graphene

The established application of graphene in organic/inorganic spin‐valve spintronic assemblies is as a spin‐transport channel for spin‐polarized electrons injected from ferromagnetic substrates. To generate and control spin injection without such substrates, the graphene backbone must be imprinted with spin‐polarized states and itinerant‐like spins. Computations suggest that such states should emerge in graphene derivatives incorporating pyridinic nitrogen. The synthesis and electronic properties of nitrogen‐doped graphene (N content: 9.8%), featuring both localized spin centers and spin‐containing sites with itinerant electron properties, are reported. This material exhibits spin‐switch behavior (on–off–on) controlled by microwave irradiation at X‐band frequency. This phenomenon may enable the creation of novel types of switches, filters, and spintronic devices using sp 2 ‐only 2D systems.