@misc{oai:repo.qst.go.jp:00072730,
 author = {李, 松田 and 境, 誠司 and 圓谷, 志郎 and Naramoto, Hiroshi and 渡邉, 貴弘 and 桜庭裕弥 and 雨宮, 健太 and B. Sorokin, Pavel and Songtian, Li and Sakai, Seiji and Entani, Shiro and Naramoto, Hiroshi},
 month = {Mar},
 note = {The low spin signal and tiny magneto-resistance is becoming a central issue in graphene-spintronic devices [1] in which conventional ferromagnets (FMs) such as Ni, Co, Fe of low spin polarization were used. Adopting highly spin-polarized material such as half-metal into graphene/FM heterostructure can be the most effective way to enhance the performance of graphene-spintronics device, experimental demonstration, however, is still lacking. This study, for the first time, reports a new heterostructure consisting of a single layer graphene (SLG) synthesized by high-vacuum chemical vapor deposition (CVD) on Co2FeGe0.5Ga0.5 (CFGG) Heusler alloy whose half-metallicity has been confirmed experimentally [2].
  CFGG layer with a thickness of 50 nm was epitaxially grown on a MgO(001) single-crystal substrate by magnetron sputtering at room temperature. The CFGG/MgO sample was then transferred into a CVD chamber for graphene synthesis. SLG was successfully synthesized on CFGG by optimizing the CVD process. Fig. 1 shows the STM image taken from the synthesized SLG/CFGG heterostructure, which reveals an epitaxial growth of SLG on CFGG. Due the large lattice-mismatch between CFGG and graphene, moiré pattern of graphene is observed. Fig. 2 shows the C K-edge XAS spectra of the SLG/CFGG heterostructure obtained by changing the incidence angle of a linearly polarized x-ray beam. The peak intensity from the π* and σ* state of graphene shows an opposite behavior of incidence-angle dependence, convincing the formation of a graphitic structure. Strikingly, the peak from the π* state of grapene observed here is very sharp, indicating a weak chemical bonding between graphene and CFGG. It makes the SLG/CFGG heterostructure unique from other graphene/FM systems such as SLG/Ni, Co, Fe which have received intensive studies so far. The quasi-freestanding nature of graphene on CFGG makes the SLG/CFGG heterostructure extremely promising for high-performance spintronic devices.
[1] Han et al. Nat. Nanotechnol. 9, 794-807 (2014); [2] Li et al. Appl. Phys. Lett. 103, 042405 (2013)., 第65回応用物理学会春季講演会},
 title = {First Direct Synthesis of Graphene/Half-metallic Heusler Alloy Heterostructure for Spintronic Device Applications},
 year = {2018}
}