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物性・原理

Efficient Spin-Polarized Injection into Graphene from Magnetic Oxide Contact---Opening a way to High-Speed and Energy-Efficient Quantum Information System---

 On July 22, 2016, National Institutes for Quantum and Radiological Science and Technology (QST), National Institute for Material Science (NIMS), and University of Tsukuba announced that a collaborative research group has succeeded in controlling spin polarization in graphene by magnetic oxide contact. Details were published in ACS Nano with lead author Seiji Sakai of QST *.

 Quantum information processing, where the information carrier is electron spin instead of electron charge, is expected to be a basis for the next generation high-speed and energy efficient information system. Spin based electronics is named as "spintronics", and its basic processes are spin generation and transport. Graphene will be an excellent transport medium, however, efficient spin injection and detection of spin in graphene have been challenging issues.

 The research group succeeded in injecting polarized spin into graphene efficiently by using magnetic oxide contact, consisting of junctions of graphene and half-metallic manganite La0.7Sr0.3MnO3 (LSMO) instead of magnetic material contact conventionally used. Surface-sensitive spectroscopy utilizing spin-polarized He atom beams and ab initio calculations confirmed the control of spin polarization in graphene.

* Seiji Sakai, Sayani Majumdar, Zakhar I. Popov, Pavel V. Avramov, Shiro Entani, Yuri Hasegawa, Yoichi Yamada, Hannu Huhtinen, Hiroshi Naramoto, Pavel B. Sorokin, and Yasushi Yamauchi, "Proximity-Induced Spin Polarization of Graphene in Contact with Half-Metallic Manganite", ACS Nano, Article ASAP, DOI: 10.1021/acsnano.6b02424; Publication Date (Web): July 20, 2016