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2015 年度 実施状況報告書

Topological Transitions in Spin Transport in Nanostructures

研究課題

研究課題/領域番号 26390014
研究機関国立研究開発法人理化学研究所

研究代表者

サーリコスキ ヘンリー  国立研究開発法人理化学研究所, 創発物性科学研究センター, 研究員 (50722245)

研究分担者 多々良 源  国立研究開発法人理化学研究所, その他部局等, その他 (10271529)
研究期間 (年度) 2014-04-01 – 2017-03-31
キーワードspin / spintronics / topology / magnetism / antiferromagnet
研究実績の概要

The research project has focused on topological effects in spin interference and has progressed very well as planned. This fiscal year a research paper titled "Effective geometric phases and topological transitions in SO(3) and SU(2) rotations" has been published in Journal of Physics: Condensed Matter (http://dx.doi.org/10.1088/0953-8984/28/16/166002). The paper describes a surprising analogy between classical systems and quantum spin systems and shows that topological transition is related to geometry of rotations in both cases. This research result has been reported in a number of conferences, e.g. in a German Physical Society meeting in Regensburg March 2016 and Japanese Physical Society Meeting in Sendai March 2016.
In addition to this progress in spin the project has focused on spin effects in metals and a manuscript on domain wall motion in synthetic antiferromagnets was prepared in collaboration with experimentalists at University of Leeds and submitted to Nature Nanotechnology. A preprint is available at http://arxiv.org/abs/1604.07992
A central finding in this work a huge reduction in the threshold current in such synthetic antiferromagnets in comparison to single-layer ferromagnetic systems. Theoretical modeling performed in this project indicated that this is due to strongly anisotropic layer coupling in the presence of nonadiabatic driving. The results were presented in the MMM-Intermag meeting in San Diego in January 2016.

JSPS funding was acknowledged in these papers/manuscripts and during talks.

現在までの達成度 (区分)
現在までの達成度 (区分)

1: 当初の計画以上に進展している

理由

The surprising results have lead to the above papers/manuscripts and have opened new prospects for future research.

今後の研究の推進方策

Plans for future include collaboration with Junsaku Nitta's group towards experimental realisation of our predicted topological effects in spin interference. In addition details of the theoretical work indicating stability of the topological transition will be published in a follow-up paper. Moreover, the project will in future focus on larger quantum networks where spin interference effects would be more intricate and lead to complex effects. These are computationally heavier and will be performed at Hokusai supercomputers at the Advanced Center for Computing and Communications (ACCC) at RIKEN.

次年度使用額が生じた理由

A bit of funding (5%) was left over to the next fiscal year.

次年度使用額の使用計画

The incurring amount will be used for travelling to conferences.

  • 研究成果

    (4件)

すべて 2016

すべて 雑誌論文 (1件) (うち国際共著 1件、 査読あり 1件、 オープンアクセス 1件、 謝辞記載あり 1件) 学会発表 (3件)

  • [雑誌論文] Effective geometric phases and topological transitions in SO(3) and SU(2) rotations2016

    • 著者名/発表者名
      Henri Saarikoski, Jose Pablo Baltanas, J Enrique Vazquez-Lozano, Junsaku Nitta and Diego Frustaglia
    • 雑誌名

      Journal of Physics: Condensed Matter

      巻: 28 ページ: 166002

    • DOI

      10.1088/0953-8984/28/16/166002

    • 査読あり / オープンアクセス / 国際共著 / 謝辞記載あり
  • [学会発表] Topological Transitions in Spin Interferometers2016

    • 著者名/発表者名
      Henri Saarikoski
    • 学会等名
      Japanese Physical Society Meeting
    • 発表場所
      Tohoku Gakuin University, Sendai, Japan
    • 年月日
      2016-03-20
  • [学会発表] Effective geometric phases and topological transitions in SO(3) and SU(2) rotations2016

    • 著者名/発表者名
      Henri Saarikoski
    • 学会等名
      German Physical Society (DPG) spring meeting
    • 発表場所
      University of Regensburg, Regensburg, Germany
    • 年月日
      2016-03-10
  • [学会発表] Very low critical current density for motion of coupled domain walls in synthetic ferrimagnet nanowires2016

    • 著者名/発表者名
      Henri Saarikoski
    • 学会等名
      MMM-Intermag conference
    • 発表場所
      Hotel Hilton, San Diego, the US
    • 年月日
      2016-01-13

URL: 

公開日: 2017-01-06  

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