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Room-temperature chiral magnetic skyrmions in ultrathin magnetic nanostructures

Nature Nanotechnology volume 11, pages 449–454 (2016)Cite this article

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A Corrigendum to this article was published on 04 August 2017

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Abstract

Magnetic skyrmions are chiral spin structures with a whirling configuration. Their topological properties, nanometre size and the fact that they can be moved by small current densities have opened a new paradigm for the manipulation of magnetization at the nanoscale. Chiral skyrmion structures have so far been experimentally demonstrated only in bulk materials and in epitaxial ultrathin films, and under an external magnetic field or at low temperature. Here, we report on the observation of stable skyrmions in sputtered ultrathin Pt/Co/MgO nanostructures at room temperature and zero external magnetic field. We use high lateral resolution X-ray magnetic circular dichroism microscopy to image their chiral Néel internal structure, which we explain as due to the large strength of the Dzyaloshinskii–Moriya interaction as revealed by spin wave spectroscopy measurements. Our results are substantiated by micromagnetic simulations and numerical models, which allow the identification of the physical mechanisms governing the size and stability of the skyrmions.

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Figure 1: Imaging of the chiral Néel structure of domain walls using XMCD-PEEM magnetic microscopy.
Figure 2
Figure 3: Magnetic skyrmion observed at room temperature and zero external magnetic field.
Figure 4: Micromagnetic simulations.
Figure 5: Effect of an external perpendicular magnetic field.
Figure 6: Forces acting on the the skyrmion and dependence of the skyrmion diameter on a perpendicular magnetic field and the film thickness.

Change history

  • 18 July 2017

    In the version of this Article originally published, the Dzyaloshinskii-Moriya interaction parameter, D, should have been multiplied by √3. The vertical scale of Fig. 2 has been updated accordingly as has the following sentence concerning D values: "For 5 monolayers (ML) of Co, equivalent to a total Co thickness of 1 nm, the ab initio calculations predict = 4.0 mJ m-2 whereas a lower value D = 2.6 mJ m-2 is predicted for a Pt/Co/vacuum structure." Additionally the Methods and Supplementary Information have been updated to correct the experimental multilayer composition to: "Ta(3)/Pt(3)/Co(0.5-1)/MgOx/Ta(2) (thickness in nm)".

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Acknowledgements

The authors would like to thank A. Thiaville, M. Cubukcu, L. Camosi, M. Caminale and W. Savero-Torres for discussions and their help in experiments. For their contribution to the CIRCE beamline at the Alba synchrotron, we would like to thank C. Escudero, V. Perez-Dieste, E. Pellegrin, J. Nicolas and S. Ferrer. S.P. and J.V. acknowledge the support of the Agence Nationale de la Recherche, project ANR-14-CE26-0012 (ULTRASKY).

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Authors and Affiliations

  1. Univ. Grenoble Alpes, SPINTEC, Grenoble, F-38000, France

    Olivier Boulle, Hongxin Yang, Liliana D. Buda-Prejbeanu, Olivier Klein, Mairbek Chshiev, Stéphane Auffret, Ioan Mihai Miron & Gilles Gaudin

  2. CNRS, SPINTEC, Grenoble, F-38000, France

    Olivier Boulle, Hongxin Yang, Liliana D. Buda-Prejbeanu, Olivier Klein, Mairbek Chshiev, Stéphane Auffret, Ioan Mihai Miron & Gilles Gaudin

  3. CEA, INAC-SPINTEC, Grenoble, F-38000, France

    Olivier Boulle, Hongxin Yang, Liliana D. Buda-Prejbeanu, Olivier Klein, Mairbek Chshiev, Stéphane Auffret, Ioan Mihai Miron & Gilles Gaudin

  4. CNRS, Institut Néel, 25 avenue des Martyrs, B.P. 166, Grenoble Cedex 9, 38042, France

    Jan Vogel, Stefania Pizzini & Dayane de Souza Chaves

  5. Univ. Grenoble Alpes, Institut Néel, 25 avenue des Martyrs, B.P. 166, Grenoble Cedex 9, 38042, France

    Jan Vogel, Stefania Pizzini & Dayane de Souza Chaves

  6. Elettra-Sincrotrone, S.C.p.A, S.S 14 - km 163.5 in AREA Science Park 34149 Basovizza, Trieste, Italy

    Andrea Locatelli, Tevfik Onur Menteş & Alessandro Sala

  7. LSPM (CNRS-UPR 3407), Université Paris 13, Sorbonne Paris Cité, 99 avenue Jean-Baptiste Clément, Villetaneuse, 93430, France

    Mohamed Belmeguenai, Yves Roussigné, Andrey Stashkevich & Salim Mourad Chérif

  8. ALBA Synchrotron Light Facility, Carretera BP 1413, Km. 3.3, Cerdanyola del Vallès, Barcelona, 08290, Spain

    Lucia Aballe & Michael Foerster

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  1. Olivier Boulle
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Contributions

O.B. conceived and designed the experiments. O.B., J.V., S.P., D.S.C., A.L, T.O.M., A.S., L.A., M.F. participated in the XMCD-PEEM experiments. O.B and J.V. analysed the microscopy data. H.Y. and M.C. carried out the ab initio calculations. O.B., L.B-D. and O.K. carried out the micromagnetic simulations, O.B. carried out the numerical calculations, S.A. deposited the magnetic multilayers, M.B., Y.R., A.S. carried out the BLS experiments. O.B. wrote the manuscript. All authors discussed the results and commented on the manuscript.

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Correspondence to Olivier Boulle.

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Boulle, O., Vogel, J., Yang, H. et al. Room-temperature chiral magnetic skyrmions in ultrathin magnetic nanostructures. Nature Nanotech 11, 449–454 (2016). https://doi.org/10.1038/nnano.2015.315

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