Depth-resolved XMCD study on single- and bi-layer graphene / Ni structures

Matsumoto, Yoshihiro; Entani, Shiro; Otomo, Manabu; Avramov, P.; Naramoto, Hiroshi*; Amemiya, Kenta*; Sakai, Seiji

The electronic and magnetic properties of the single-layer graphene (SLG)/Ni(111) and bilayer graphene (BLG)/Ni(111) structures are investigated by using the X-ray magnetic circular dichroism (XMCD) spectroscopy. For the SLG/Ni(111) structure, an intense XMCD signal was observed in the C K-edge XMCD spectrum measured by reversing the remanent magnetization of Ni(111). This indicates that spin polarization is induced in the -orbitals of SLG by the contact with Ni(111) even at room temperature. More interestingly, the BLG/Ni(111) structure is found to show the C K-edge XMCD signal whose intensity changes dramatically with the probing depth. On the other hand, Ni L-edge XMCD spectrum demonstrated that the magnetization of Ni decreases by 20-30% within a few atomic layers from the SLG/Ni(111) interfaces, possibly associated with the formation of C-Ni bonds.