Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Controlled transformation of skyrmions and antiskyrmions in a non-centrosymmetric magnet

Nature Nanotechnology volume 15, pages 181–186 (2020)Cite this article

Subjects

Abstract

Control of topological spin textures in magnetic systems may enable future spintronic applications. Magnetic field pulses can switch the vortex polarity1 or the winding number of magnetic bubbles2. Thermal energy can reverse the helicity of skyrmions3 and induce the transformation between meron and skyrmion by modifying the in-plane anisotropy4,5. Among the various topological spin textures, skyrmions6,7 and antiskyrmions8,9,10 are nanometric spin-whirling structures carrying integer topological charges (N) of −1 and +1 (refs. 7,11,12), respectively, and can be observed in real space8,13. They exhibit different dynamical properties under current flow14,15,16,17,18, for example, opposite signs for the topological Hall effect. Here we observe, in real space, transformations among antiskyrmions, non-topological (NT) bubbles and skyrmions (with N of +1, 0 and −1, respectively) and their lattices in a non-centrosymmetric Heusler magnet, Mn1.4Pt0.9Pd0.1Sn, with D2d symmetry. Lorentz transmission electron microscopy images under out-of-plane magnetic fields show a square lattice of square-shaped antiskyrmions near the Curie temperature and a triangular lattice of elliptically deformed skyrmions with opposite helicities at lower temperatures. The clockwise and counter-clockwise helicities of the skyrmions originate from Dzyaloshinskii–Moriya interactions with opposite signs along the [100] and [010] directions, respectively. A variation of the in-plane magnetic field induces a topological transformation from antiskyrmions to NT-bubbles and to skyrmions, which is accompanied by a change of the lattice geometry. We also demonstrate control of the helicity of skyrmions by variations of the in-plane magnetic field. These results showcase the control of the topological nature of spin configurations in complex magnetic systems.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Square antiskyrmion lattice and an antiskyrmion-to-skyrmion transformation at room temperature in a Mn1.4Pt0.9Pd0.1Sn magnet with D2d symmetry.
Fig. 2: In-plane field-induced transformation between antiskyrmions and NT-bubbles at room temperature.
Fig. 3: In-plane field-induced changes of the symmetry of magnetic textures in a magnet with D2d symmetry.
Fig. 4: Control of the helicity of elliptically deformed skyrmions by the in-plane field at 250 K and a phase diagram observed in the MnPtPdSn thin plate.

Similar content being viewed by others

Data availability

The data that support the findings of this study are available from the corresponding author upon reasonable request.

References

  1. Hertel, R., Gliga, S., Fähnle, M. & Schneider, C. M. Ultrafast nanomagnetic toggle switching of vortex cores. Phys. Rev. Lett. 98, 117201 (2007).

    Article  CAS  Google Scholar 

  2. Moutafis, C., Komineas, S. & Bland, J. A. C. Dynamics and switching processes for magnetic bubbles in nanoelements. Phys. Rev. B 79, 224429 (2009).

    Article  Google Scholar 

  3. Yu, X. Z. et al. Thermally activated helicity reversals of skyrmions. Phys. Rev. B 93, 134417 (2016).

    Article  Google Scholar 

  4. Yu, X. Z. et al. Transformation between meron and skyrmion topological spin textures in a chiral magnet. Nature 564, 95–98 (2018).

    Article  CAS  Google Scholar 

  5. Lin, S. Z., Saxena, A. & Batista, C. D. Skyrmion fractionalization and merons in chiral magnets with easy-plane anisotropy. Phys. Rev. B 91, 224407 (2015).

    Article  Google Scholar 

  6. Skyrme, T. H. R. A unified field theory of mesons and baryons. Nucl. Phys. 31, 556–569 (1962).

    Article  CAS  Google Scholar 

  7. Nagaosa, N. & Tokura, Y. Topological properties and dynamics of magnetic skyrmions. Nat. Nanotechnol. 8, 899–911 (2013).

    Article  CAS  Google Scholar 

  8. Nayak, A. K. et al. Magnetic antiskyrmions above room temperature in tetragonal Heusler materials. Nature 548, 561–566 (2017).

    Article  CAS  Google Scholar 

  9. Bogdanov, A. N. & Yablonskii, D. A. Thermodynamically stable ‘vortices’ in magnetically ordered crystals. The mixed state of magnets. Sov. Phys. JETP 68, 101–103 (1989).

    Google Scholar 

  10. Camosi, L. et al. Anisotropic Dzyaloshinskii–Moriya interaction in ultrathin epitaxial Au/Co/W(110). Phys. Rev. B 95, 214422 (2017).

    Article  Google Scholar 

  11. Koshibae, W. & Nagaosa, N. Theory of antiskyrmions in magnets. Nat. Commun. 7, 10542 (2016).

    Article  CAS  Google Scholar 

  12. Hoffmann, M. et al. Antiskyrmions stabilized at interfaces by anisotropic Dzyaloshinskii–Moriya interactions. Nat. Commun. 8, 308 (2017).

    Article  Google Scholar 

  13. Yu, X. Z. et al. Real-space observation of a two-dimensional skyrmion crystal. Nature 465, 901–904 (2010).

    Article  CAS  Google Scholar 

  14. Jiang, W. et al. Direct observation of the skyrmion Hall effect. Nat. Phys. 13, 162–169 (2017).

    Article  CAS  Google Scholar 

  15. Litzius, K. et al. Skyrmion Hall effect revealed by direct time-resolved X-ray microscopy. Nat. Phys. 13, 170–175 (2017).

    Article  CAS  Google Scholar 

  16. Ritzmann, U. et al. Trochoidal motion and pair generation in skyrmion and antiskyrmion dynamics under spin–orbit torques. Nat. Electron. 1, 451–457 (2018).

    Article  Google Scholar 

  17. Huang, Sying et al. Stabilization and current-induced motion of antiskyrmion in the presence of anisotropic Dzyaloshinskii–Moriya interaction. Phys. Rev. B 96, 144412 (2017).

    Article  Google Scholar 

  18. Kovalev, A. A. & Sandhoefner, S. Skyrmions and antiskyrmions in quasi-two-dimensional magnets. Front. Phys. 6, 98 (2018).

    Article  Google Scholar 

  19. Yu, X. Z. et al. Near room-temperature formation of a skyrmion crystal in thin-films of the helimagnet FeGe. Nat. Mater. 10, 106–109 (2011).

    Article  CAS  Google Scholar 

  20. Dzyaloshinsky, I. A thermodynamic theory of ‘weak’ ferromagnetism of antiferromagnetics. J. Phys. Chem. Solids 4, 241–255 (1958).

    Article  CAS  Google Scholar 

  21. Moriya, T. Anisotropic superexchange interaction and weak ferromagnetism. Phys. Rev. 120, 91–98 (1960).

    Article  CAS  Google Scholar 

  22. Rößler, U. K., Leonov, A. A. & Bogdanov, A. N. Skyrmionic textures in chiral magnets. J. Phys. Conf. Ser. 200, 022029 (2010).

    Article  Google Scholar 

  23. Bogdanov, A. N., Rößler, U. K., Wolf, M. & Müller, K.-H. Magnetic structures and reorientation transitions in noncentrosymmetric uniaxial antiferromagnets. Phys. Rev. B 66, 214410 (2002).

    Article  Google Scholar 

  24. Camosi, L., Rougemaille, N., Fruchart, O., Vogel, J. & Rohart, S. Micromagnetics of antiskyrmions in ultrathin films. Phys. Rev. B 97, 134404 (2018).

    Article  CAS  Google Scholar 

  25. Saito, M., Ishikawa, K., Taniguchi, K. & Arima, T. Magnetic control of crystal chirality and the existence of a large magneto-optical dichroism effect in CuB2O4. Phys. Rev. Lett. 101, 117402 (2008).

    Article  CAS  Google Scholar 

  26. Ishizuka, K. & Allman, B. Phase measurement of atomic resolution image using transport of intensity equation. J. Electron Microsc. 54, 191–197 (2005).

    CAS  Google Scholar 

  27. Grundy, P. J. & Herd, S. R. Lorentz microscopy of bubble domains and changes in domain wall state in hexaferrites. Phys. Status Solidi (a) 20, 295–307 (1973).

    Article  CAS  Google Scholar 

  28. Nii, Y., Sasaki, R., Iguchi, Y. & Onose, Y. Microwave magnetochiral effect in the non-centrosymmetric magnet CuB2O4. J. Phys. Soc. Jpn 86, 024707 (2017).

    Article  Google Scholar 

  29. Spaldin, N. A. & Ramesh, R. Advances in magnetoelectric multiferroics. Nat. Mater. 18, 203–212 (2019).

    Article  CAS  Google Scholar 

  30. Vansteenkiste, A. et al. The design and verification of MuMax3. AIP Adv. 4, 107133 (2014).

    Article  Google Scholar 

  31. Kurtulus, Y., Dronskowski, R., Samolyuk, G. D. & Antropov, V. P. Electronic structure and magnetic exchange coupling in ferromagnetic full Heusler alloys. Phys. Rev. B 71, 014425 (2005).

    Article  Google Scholar 

Download references

Acknowledgements

We thank Y. Taguchi and M. Ishida for enlightening discussions and technical assistance, respectively. We thank T. Kikitsu and D. Hashizume (Materials Characterization Support Team in the RIKEN Center for Emergent Matter Science) for technical support on the TEM (JEM-2100F), which was used to obtain L-TEM images. This work was partly supported by Grants-in-Aid for Scientific Research (A) (grant no. 18H03685) and Grants-in-Aid for Scientific Research on Innovative Area ‘Nano Spin Conversion Science’ (grant no. 17H05186) from JSPS, PRESTO (grant no. JPMJPR18L5, JST) and CREST (grant no. JPMJCR1874, JST).

Author information

Author notes

  1. Rina Takagi & Shinichiro Seki

    Present address: Department of Applied Physics and Institute of Engineering Innovation, University of Tokyo, Tokyo, Japan

  2. Kiyou Shibata

    Present address: Institute of Industrial Science, University of Tokyo, Meguro, Tokyo, Japan

Authors and Affiliations

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

    Licong Peng, Rina Takagi, Wataru Koshibae, Kiyou Shibata, Kiyomi Nakajima, Taka-hisa Arima, Naoto Nagaosa, Shinichiro Seki, Xiuzhen Yu & Yoshinori Tokura

  2. Department of Advanced Materials Science, University of Tokyo, Kashiwa, Japan

    Taka-hisa Arima

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

    Naoto Nagaosa & Yoshinori Tokura

  4. Tokyo College, University of Tokyo, Tokyo, Japan

    Yoshinori Tokura

Authors
  1. Licong Peng
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Rina Takagi
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Wataru Koshibae
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Kiyou Shibata
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Kiyomi Nakajima
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Taka-hisa Arima
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Naoto Nagaosa
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. Shinichiro Seki
    View author publications

    You can also search for this author in PubMed Google Scholar

  9. Xiuzhen Yu
    View author publications

    You can also search for this author in PubMed Google Scholar

  10. Yoshinori Tokura
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

X.Y., S.S. and Y.T. jointly conceived the project. L.P., K.N. and X.Y. carried out L-TEM observations and analysed the experimental data. R.T. synthesized the MnPtPdSn crystals and performed magnetic property measurements. W.K., K.S., T.-H.A. and N.N. performed the simulations. L.P., X.Y., W.K., N.N., S.S. and Y.T. wrote the manuscript. All authors discussed the data and contributed to the manuscript.

Corresponding authors

Correspondence to Licong Peng or Xiuzhen Yu.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Peer review information Nature Nanotechnology thanks Lorenzo Camosi, Mathias Kläui and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data

Extended Data Fig. 1 Lattice forms of antiskyrmions simulated by using Landau–Lifshitz–Gilbert equation.

Simulated square lattice (a) and hexagonal lattice (b) of antiskyrmions with using the energies of the exchange energy (A), D2d-type DMI, Zeeman energy, uniaxial anisotropy energy (Ku), and demagnetization energy for a and the energies including A, DMI, and Zeeman energy for b, respectively. The colour wheel in b and the triangles in a-b indicate the direction of in-plane magnetizations of the magnetic textures, whereas the dark colour indicates out-of-plane magnetizations.

Extended Data Fig. 2 Simulated L-TEM images of antiskyrmion, NT-bubble, and skyrmion.

Magnetic textures (a, d, g), simulated (b, e, h) and experimental (c, f, i) L-TEM images of a-c square-shape antiskyrmion, d-f NT-bubble, and g-i elliptic skyrmion. The colour bar indicates the normalized components of out-of-plane magnetizations in magnetic textures.

Extended Data Fig. 3 Sequential L-TEM images during the transformation process between the square antiskyrmion lattice and the triangular NT-bubble lattice.

A series of L-TEM images with varying the in-plane field along a, \([0\bar 10]\) and [010], b, \([\bar 100]\) and [100] directions showing the transformation between antiskyrmion lattice and NT-bubble lattice through a mixed state of antiskyrmions and NT-bubbles in a reproducible way. The order of L-TEM observations is shown as the red arrows.

Extended Data Fig. 4 T-H phase diagram of various magnetic textures together with several L-TEM images observed in the (001) MnPtPdSn thin plate.

a, Phase diagram and L-TEM images of isolated antiskyrmions and skyrmions under the normal field. b, Phase diagram and L-TEM image of NT-bubbles under the tilting field with 15° relative to the \([00\bar 1]\) axis. Various phases of I,II, III, VI, VII and VIII have been described in the right panels of a, b. The field directions are indicated in the upper-right images of a, b. The open circles specify the (T, µ0H) points, where we have done the L-TEM observations.

Supplementary information

Supplementary Information

Supplementary Figs. 1–4 and Discussion.

Supplementary Video 1

Numerical simulation showing dynamics of skyrmion-to-NT-bubble transformation.

Supplementary Video 2

Numerical simulation showing dynamics of skyrmion-to-NT-bubble transformation.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Peng, L., Takagi, R., Koshibae, W. et al. Controlled transformation of skyrmions and antiskyrmions in a non-centrosymmetric magnet. Nat. Nanotechnol. 15, 181–186 (2020). https://doi.org/10.1038/s41565-019-0616-6

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41565-019-0616-6

This article is cited by

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing