Interface properties of graphene-based heterostructures for spintronic applications

スピントロニクス応用に向けたグラフェン基ヘテロ構造の界面物性の研究

境 誠司; Majumdar, S.*; 圓谷 志郎; 楢本 洋*; Avramov, P.; 山内 泰*

Sakai, Seiji; Majumdar, S.*; Entani, Shiro; Naramoto, Hiroshi*; Avramov, P.; Yamauchi, Yasushi*

In this presentation, we will show our recent results on the spin-dependent electronic states of the interfaces of the single layer graphene (SLG)/magnetic material (ferromagnetic Ni and half-metallic LaSrMnO) heterostructures. The spin-polarization states of the SLG located at the top-surfaces of the heterostructures were successfully elucidated by employing spin-polarized metastable-atom deexcitation spectroscopy (SPMDS). For the SLG-Ni(111) heterostructure, it was elucidated that the positive spin polarization is induced in SLG in contrast to the negative spin-polarization of the Ni(111) surface near the Fermi level. The strong hybridization and exchange-interaction at the interface were suggested to involve this antiparallel spin polarization between SLG and Ni. For the SLG/ LaSrMnO(110) heterostructure, a remarkably large spin polarization with a positive polarization sign was suggested to be induced in SLG from the measured spin signals from the heterostructure. The large positive spin polarization is possibly induced by the proximity effect of the half-metallic LaSrMnO in association with the mixing between the highly spin polarized O 2p-derived and Mn 3d-derived states of LSMO and band of SLG. The present result showed that the effective spin manipulation could be achieved by applying magnetic oxides to the magnetic electrodes of graphene-based spintronic devices.