Magnetization of Epitaxial Graphene Induced by Magnetic Metallic Substrate

A model of the energy diagram is proposed for graphene (Gr) monolayer formed on a magnetic transition metal (MTM). The regimes of the strong and weak Gr-MTM coupling are considered; the analytical expressions have been derived for the magnetization induced by a substrate in epitaxial graphene in these regimes. It is shown that, in the strong coupling regime, a quasi-local state gives the main contribution to the magnetization; in this case, the coupling has an antiferromagnetic character. In the weak coupling regime, the main contribution to the magnetization is given by states of the d band of MTM, which leads to the ferromagnetic character of the coupling. The numerical estimations are performed for the Gr/Ni(111) and Gr/Co(poly) and they are compared with the experimental data for Gr/Ni(111) and the calculated results for Cr/Co/Ni(111). In the first case, the results agree quantitatively and, in the second case, qualitatively.