Interface-Induced Spin Polarization in Graphene on Chromia

The induced spin polarization of graphene on Cr2O3(001) is investigated using density-functional theory (DFT) and model calculations. The magnetic moment in graphene is a proximity effect and can be regarded as a second-order Stoner scenario, and similar mechanisms are likely realized for all graphene systems with an insulating magnetic substrate. In the absence of charge transfer, the magnetic moment would be quadratic in the exchange field, as contrasted to the usually encountered approximately linear dependence. The net magnetization of the graphene is small, of the order of 0.01 mu(B) per atom, but the energy-dependent spin polarization exhibits pronounced peaks that have a disproportionally strong effect on the spin-polarized electron transport and are therefore important for spin-electronics applications.