Direct probing of spin polarization in graphene on magnetic metal surface by metastable helium beam

Entani, Shiro; Otomo, Manabu; Kurahashi, Mitsunori*; Matsumoto, Yoshihiro; Avramov, P.; Naramoto, Hiroshi*; Sakai, Seiji; Yamauchi, Yasushi*

Graphene attracts much attention as the most promising material for realizing molecular spintronic devices. In the devices, the control of the spin injection/detection processes at the interface between graphene and ferromagnetic metal (FM) electrodes are crucial for the device operation and thus the elucidations of the electronic structures at the graphene/FM interface including the spin polarization in graphene is indispensable to the designing spintronic devices. In this study, the spin-polarized electronic structure of graphene on the FM surfaces is investigated by spin-polarized metastable deexcitation spectroscopy (SPMDS). The SPMDS measurements indicated that new electronic states caused by splitting and mixing of the graphene -orbitals and the substrate states appeared around the Fermi energy. Spin asymmetry analysis of the SPMDS spectra revealed that the spin polarization in which majority spin is dominant was induced in the new electronic states at around the Fermi energy.