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Geometrically stabilized skyrmionic vortex in FeGe tetrahedral nanoparticles

Nature Materials volume 21, pages 305–310 (2022)Cite this article

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Abstract

The concept of topology has dramatically expanded the research landscape of magnetism, leading to the discovery of numerous magnetic textures with intriguing topological properties. A magnetic skyrmion is an emergent topological magnetic texture with a string-like structure in three dimensions and a disk-like structure in one and two dimensions. Skyrmions in zero dimensions have remained elusive due to challenges from many competing orders. Here, by combining electron holography and micromagnetic simulations, we uncover the real-space magnetic configurations of a skyrmionic vortex structure confined in a B20-type FeGe tetrahedral nanoparticle. An isolated skyrmionic vortex forms at the ground state and this texture shows excellent robustness against temperature without applying a magnetic field. Our findings shed light on zero-dimensional geometrical confinement as a route to engineer and manipulate individual skyrmionic metastructures.

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Fig. 1: Morphology and crystallography of FeGe tetrahedral particles.
Fig. 2: Skyrmionic vortex confined in a 145 nm FeGe tetrahedral particle.
Fig. 3: Observed and simulated projections of non-trivial magnetic states.
Fig. 4: Chiral edge state in a tetrahedron.
Fig. 5: Magnetic phase diagram of the FeGe tetrahedral particle system.

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Data availability

The data that support the findings of this study are available within the article and its Supplementary Information. Any other relevant data are also available upon reasonable request from the corresponding authors.

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Acknowledgements

K.N. was supported by a Grant-in-Aid for Scientific Research (B) (number 19H02418) and for Challenging Research (Exploratory) (number 19K22052) from the JSPS. X.Y. was supported by a Grant-in-Aid for Scientific Research (A) (number 19H00660) from the JSPS and JST CREST (grant number JPMJCR20T1). N.N. was supported by JST CREST (grant number JPMJCR1874). A.C.B. and J.Z. acknowledge support from the US Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES) under award number DE-SC0020221. Y.L. was supported by the Special Postdoctoral Researcher programme of RIKEN. N.M., M.J.S. and S.J. were supported by US NSF grant ECCS-1609585. M.J.S. also acknowledges support from the NSF Graduate Research Fellowship Program.

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Author notes

  1. These authors contributed equally: Kodai Niitsu, Yizhou Liu.

Authors and Affiliations

  1. RIKEN Center for Emergent Matter Science (CEMS), Wako, Japan

    Kodai Niitsu, Yizhou Liu, Xiuzhen Yu, Daisuke Shindo, Naoto Nagaosa & Yoshinori Tokura

  2. Department of Materials Science and Engineering, Kyoto University, Kyoto, Japan

    Kodai Niitsu

  3. Department of Physics and Astronomy, University of New Hampshire, Durham, NH, USA

    Alexander C. Booth & Jiadong Zang

  4. Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA

    Nitish Mathur, Matthew J. Stolt & Song Jin

  5. Materials Science Program, University of New Hampshire, Durham, NH, USA

    Jiadong Zang

  6. Department of Applied Physics, University of Tokyo, Tokyo, Japan

    Naoto Nagaosa & Yoshinori Tokura

  7. Tokyo College, University of Tokyo, Tokyo, Japan

    Yoshinori Tokura

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  1. Kodai Niitsu
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Contributions

S.J. and Y.T. conceived the project. N.M., M.J.S. and S.J. synthesized the FeGe particles. Y.L., A.C.B. and J.Z. performed the micromagnetic simulations. K.N. performed the EH observations and model-based simulations. K.N., Y.L. and J.Z. wrote the manuscript. All authors discussed the data and revised the manuscript.

Corresponding authors

Correspondence to Kodai Niitsu or Jiadong Zang.

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Nature Materials thanks Shawn D. Pollard and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary information

Supplementary Information

Supplementary notes 1–5, references 1–7, Figs. 1–22 and captions of Movies 1–4.

Supplementary Video 1

Simulated 3D view of the skyrmionic vortex in a 145 nm tetrahedron (in-plane (xy plane) magnetic component).

Supplementary Video 2

Simulated 3D view of the skyrmionic vortex in a 145 nm tetrahedron (out-of-plane (z axis) magnetic component).

Supplementary Video 3

Sliced vector plots of the skyrmionic vortex in a 145 nm tetrahedron.

Supplementary Video 4

Sliced vector plots of the skyrmionic vortex in a 185 nm tetrahedron.

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Niitsu, K., Liu, Y., Booth, A.C. et al. Geometrically stabilized skyrmionic vortex in FeGe tetrahedral nanoparticles. Nat. Mater. 21, 305–310 (2022). https://doi.org/10.1038/s41563-021-01186-x

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