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Nucleation, stability and current-induced motion of isolated magnetic skyrmions in nanostructures

Abstract

Magnetic skyrmions are topologically stable spin configurations, which usually originate from chiral interactions known as Dzyaloshinskii–Moriya interactions. Skyrmion lattices were initially observed in bulk non-centrosymmetric crystals, but have more recently been noted in ultrathin films, where their existence is explained by interfacial Dzyaloshinskii–Moriya interactions induced by the proximity to an adjacent layer with strong spin–orbit coupling. Skyrmions are promising candidates as information carriers for future information-processing devices due to their small size (down to a few nanometres) and to the very small current densities needed to displace skyrmion lattices. However, any practical application will probably require the creation, manipulation and detection of isolated skyrmions in magnetic thin-film nanostructures. Here, we demonstrate by numerical investigations that an isolated skyrmion can be a stable configuration in a nanostructure, can be locally nucleated by injection of spin-polarized current, and can be displaced by current-induced spin torques, even in the presence of large defects.

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Figure 1: Isolated skyrmion in a nanodisk (diameter, 80 nm).
Figure 2: Injection of skyrmions in a nanodisk.
Figure 3: Current-induced motion of skyrmions in a nanotrack.
Figure 4: Pinning of the current-induced motion of skyrmions by defects in a 40-nm-wide nanotrack.

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Acknowledgements

We thank N. Reyren, C. Luchaire-Moreau, J. M. George and J. V. Kim for discussions, C. Deranlot for material deposition, and N. Van Horne, K. Bouzehouane and R. Mattana for magnetic measurements.

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Contributions

V.C. and A.F. conceived and coordinated the project. J.S. performed the micromagnetic simulations. S.R. implemented the DMI in the OOMMF code. J.S., V.C., S.R, A.T. and A.F. interpreted the results. J.S, V.C. and A.F. prepared the manuscript. All authors commented on the manuscript.

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Correspondence to V. Cros.

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The authors declare no competing financial interests.

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Sampaio, J., Cros, V., Rohart, S. et al. Nucleation, stability and current-induced motion of isolated magnetic skyrmions in nanostructures. Nature Nanotech 8, 839–844 (2013). https://doi.org/10.1038/nnano.2013.210

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