Giant magnetic anisotropy of transition-metal dimers on defected graphene

Continuous miniaturization of magnetic units in spintronics and quantum computing devices inspires efforts to search for magnetic nanostructures with large magnetic anisotropy energy (MAE). Typical nanostructures including molecular magnets, magnetic nanoclusters and magnetic nanowires have MAEs of a few meV so their blocking temperature is mostly lower than 50 K. In this work, we demonstrated the feasibility of achieving giant MAE in systems with transition metal dimers on defected and decorated graphene, based on density functional theory calculations. In particular, either a Pt-Ir dimer on a single vacancy or an Os-Ru dimer on a nitrogen-decorated divacancy possesses an MAE larger than 60 meV and high structural stability. Interestingly, their magnetic anisotropy can be conveniently manipulated by using external electric field. These features make them good candidates for the use in room temperature spintronics and quantum computing devices.