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Current-induced skyrmion dynamics in constricted geometries

Nature Nanotechnology volume 8, pages 742–747 (2013)Cite this article

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A Corrigendum to this article was published on 05 February 2014

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Abstract

Magnetic skyrmions—vortex-like swirling spin structures with a quantized topological number that are observed in chiral magnets—are appealing for potential applications in spintronics because it is possible to control their motion with ultralow current density. To realize skyrmion-based spintronic devices, it is essential to understand skyrmion motions in confined geometries. Here we show by micromagnetic simulations that the current-induced motion of skyrmions in the presence of geometrical boundaries is very different from that in an infinite plane. In a channel of finite width, transverse confinement results in steady-state characteristics of the skyrmion velocity as a function of current that are similar to those of domain walls in ferromagnets, whereas the transient behaviour depends on the initial distance of the skyrmion from the boundary. Furthermore, we show that a single skyrmion can be created by an electric current in a simple constricted geometry comprising a plate-shaped specimen of suitable size and geometry. These findings could guide the design of skyrmion-based devices in which skyrmions are used as information carriers.

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Figure 1: Steady-state velocity of current-induced motion of a skyrmion after the transient time in a finite-width channel.
Figure 2: Transient behaviour of the current-induced motion of a skyrmion in a wide channel.
Figure 3: Creation process for skyrmions.
Figure 4: Rates of skyrmion creation.
Figure 5: Two types of skyrmion motion near the edge of the magnetic region.

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  • 06 January 2014

    In the version of this Article originally published, the authors' competing financial interests were not included. This has now been corrected in the online versions of the Article.

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Acknowledgements

The authors thank Y. Tokura, M. Kawasaki and X.Z. Yu for discussions. This work was supported by Grant-in-Aids for Scientific Research (nos 24224009, 25870169 and 25287088) from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan, the Strategic International Cooperative Program (Joint Research Type) from Japan Science and Technology Agency and by the Funding Program for World-Leading Innovative R&D on Science and Technology (FIRST Program). M.M. was supported by the G-COE Program ‘Physical Sciences Frontier’ from MEXT.

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Authors and Affiliations

  1. Department of Applied Physics, The University of Tokyo, 7-3-1, Hongo, Tokyo, 113-8656, Bunkyo-ku, Japan

    Junichi Iwasaki & Naoto Nagaosa

  2. Department of Physics and Mathematics, Aoyama Gakuin University, 5-10-1, Sagamihara, 229-8558, Fuchinobe, Japan

    Masahito Mochizuki

  3. RIKEN Center for Emergent Matter Science (CEMS), Saitama, 351-0198, Wako, Japan

    Naoto Nagaosa

Authors
  1. Junichi Iwasaki
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Contributions

J.I. performed the numerical calculations. J.I., M.M. and N.N. contributed to analysing the data and writing the paper.

Corresponding authors

Correspondence to Junichi Iwasaki or Naoto Nagaosa.

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Competing interests

N.N., M.M. and J.I. have a Japanese patent application for this work, number JPO 2013-045860, 'Creation, annihilation of skyrmion and its application to magnetic devices'.

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Iwasaki, J., Mochizuki, M. & Nagaosa, N. Current-induced skyrmion dynamics in constricted geometries. Nature Nanotech 8, 742–747 (2013). https://doi.org/10.1038/nnano.2013.176

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