Symmetry-breaking interlayer Dzyaloshinskii–Moriya interactions in synthetic antiferromagnets

Abstract

The magnetic interfacial Dzyaloshinskii–Moriya interaction (DMI) in multilayered thin films can lead to chiral spin states, which are of paramount importance for future spintronic technologies1,2. Interfacial DMI typically manifests as an intralayer interaction, mediated via a paramagnetic heavy metal in systems lacking inversion symmetry3. Here we show that, by designing synthetic antiferromagnets with canted magnetization states4,5, it is also possible to observe direct evidence of the interfacial interlayer DMI at room temperature. The interlayer DMI breaks the symmetry of the magnetic reversal process via the emergence of non-collinear spin states, which results in chiral exchange-biased hysteresis loops. The spin chiral interlayer interactions reported here are expected to manifest in a range of multilayered thin-film systems, opening up as yet unexplored avenues for the development and exploitation of chiral effects in magnetic heterostructures6,7,8.

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Fig. 1: Interlayer DMI investigations in canted SAFs.
Fig. 2: Chiral exchange bias due to the interlayer DMI.
Fig. 3: Bias field dependence on CoFeB thickness.
Fig. 4: Emergence of spin modulations.

Data availability

All data associated to this publication is available via Enlighten, the University of Glasgow public repository. All metadata for this publication is available via the following link: https://doi.org/10.5525/gla.researchdata.787.

Code availability

The atomistic and macrospin Monte Carlo codes used for this study are available from the corresponding authors on reasonable request.

Change history

  • 24 June 2019

    In the original version of this article originally published, an oversight during the production process meant that ref. 16 was not updated from the preprint version; this has now been amended and the updated reference reads ‘Han, D.-S. Long-range chiral exchange interaction in synthetic antiferromagnets. Nat. Mater. https://doi.org/10.1038/s41563-019-0370-z (2019)’.

References

  1. 1.

    Wiesendanger, R. Nanoscale magnetic skyrmions in metallic films and multilayers: a new twist for spintronics. Nat. Rev. Mater. 1, 16044 (2016).

  2. 2.

    Sander, D. et al. The 2017 magnetism roadmap. J. Phys. D 50, 363001 (2017).

  3. 3.

    Hellman, F. et al. Interface-induced phenomena in magnetism. Rev. Mod. Phys. 89, 025006 (2017).

  4. 4.

    Ummelen, F. C. et al. Controlling the canted state in antiferromagnetically coupled magnetic bilayers close to the spin reorientation transition. Appl. Phys. Lett. 110, 102405 (2017).

  5. 5.

    Fernandez-Pacheco, A. et al. Dynamic selective switching in antiferromagnetically-coupled bilayers close to the spin reorientation transition. Appl. Phys. Lett. 105, 092408 (2014).

  6. 6.

    Lavrijsen, R. et al. Magnetic ratchet for three-dimensional spintronic memory and logic. Nature 493, 647–650 (2013).

  7. 7.

    Fernández-Pacheco, A. et al. Three dimensional nanomagnetism. Nat. Commun. 8, 15756 (2017).

  8. 8.

    Baltz, V. et al. Antiferromagnetic spintronics. Rev. Mod. Phys. 90, 015005 (2018).

  9. 9.

    Woo, S. et al. Observation of room-temperature magnetic skyrmions and their current-driven dynamics in ultrathin metallic ferromagnets. Nat. Mater. 15, 501–506 (2016).

  10. 10.

    Boulle, O. et al. Room-temperature chiral magnetic skyrmions in ultrathin magnetic nanostructures. Nat. Nanotechnol. 11, 449–454 (2016).

  11. 11.

    Jué, E. et al. Chiral damping of magnetic domain walls. Nat. Mater. 15, 272–277 (2015).

  12. 12.

    Ryu, K.-S., Thomas, L., Yang, S.-H. & Parkin, S. Chiral spin torque at magnetic domain walls. Nat. Nanotechnol. 8, 527–533 (2013).

  13. 13.

    Levy, P. M. & Fert, A. Anisotropy induced by nonmagnetic impurities in Cu Mn spin-glass alloys. Phys. Rev. B 23, 4667–4690 (1981).

  14. 14.

    Crépieux, A. & Lacroix, C. Dzyaloshinsky–Moriya interactions induced by symmetry breaking at a surface. J. Magn. Magn. Mater. 182, 341–349 (1998).

  15. 15.

    Vedmedenko, E. Y., Arregi, J. A., Riego, P. & Berger, A. Interlayer Dzyaloshinskii–Moriya interactions. Preprint at https://arxiv.org/abs/1803.10570 (2018).

  16. 16.

    Han, D.-S. et al. Long-range chiral exchange interaction in synthetic antiferromagnets. Nat. Mater. https://doi.org/10.1038/s41563-019-0370-z (2019).

  17. 17.

    Dupé, B., Hoffmann, M., Paillard, C. & Heinze, S. Tailoring magnetic skyrmions in ultra-thin transition metal films. Nat. Commun. 5, 4030 (2014).

  18. 18.

    Yang, H., Thiaville, A., Rohart, S., Fert, A. & Chshiev, M. Anatomy of Dzyaloshinskii–Moriya interaction at Co/Pt interfaces. Phys. Rev. Lett. 115, 267210 (2015).

  19. 19.

    Ives, A. J. R., Bland, J. A. C., Hicken, R. J. & Daboo, C. Oscillatory biquadratic coupling in Fe/Cr/Fe(001). Phys. Rev. B 55, 12428–12438 (1997).

  20. 20.

    Han, D. S. et al. Asymmetric hysteresis for probing Dzyaloshinskii–Moriya interaction. Nano Lett. 16, 4438–4446 (2016).

  21. 21.

    Pizzini, S. et al. Chirality-induced asymmetric magnetic nucleation in Pt/Co/AlOx ultrathin microstructures. Phys. Rev. Lett. 113, 047203 (2014).

  22. 22.

    Lee, J.-H. et al. Domain imaging during soliton propagation in a 3D magnetic ratchet. SPIN 03, 1340013 (2013).

  23. 23.

    Kisielewski, M. et al. Drastic changes of the domain size in an ultrathin magnetic film. J. Appl. Phys. 93, 6966–6968 (2003).

  24. 24.

    Kimura, T., Lashley, J. C. & Ramirez, A. P. Inversion-symmetry breaking in the noncollinear magnetic phase of the triangular-lattice antiferromagnet CuFeO2. Phys. Rev. B 73, 220401 (2006).

  25. 25.

    Ferré, J. et al. Magnetization-reversal processes in an ultrathin Co/Au film. Phys. Rev. B 55, 15092–15102 (1997).

  26. 26.

    Liu, Y., Zhou, B. & Zhu, J.-G. Field-free magnetization switching by utilizing the Spin Hall effect and interlayer exchange coupling of iridium. Sci. Rep. 9, 325 (2019).

  27. 27.

    Romming, N. et al. Competition of Dzyaloshinskii–Moriya and higher-order exchange interactions in Rh/Fe atomic bilayers on Ir(111). Phys. Rev. Lett. 120, 207201 (2018).

  28. 28.

    Shahbazi, K. et al. Domain-wall motion and interfacial Dzyaloshinskii–Moriya interactions in Pt/Co /Ir(t Ir)/Ta multilayers. Phys. Rev. B 99, 094409 (2019).

  29. 29.

    Di, K. et al. Asymmetric spin–wave dispersion due to Dzyaloshinskii–Moriya interaction in an ultrathin Pt/CoFeB film. Appl. Phys. Lett. 106, 052403 (2015).

  30. 30.

    Wiese, N. et al. Antiferromagnetically coupled CoFeB/Ru/CoFeB trilayers. Appl. Phys. Lett. 85, 2020 (2004).

  31. 31.

    Lavrijsen, R. et al. Tuning the interlayer exchange coupling between single perpendicularly magnetized CoFeB layers. Appl. Phys. Lett. 100, 052411 (2012).

  32. 32.

    Raanaei, H. et al. Imprinting layer specific magnetic anisotropies in amorphous multilayers. J. Appl. Phys. 106, 023918 (2009).

  33. 33.

    Kang, S. P. et al. The spin structures of interlayer coupled magnetic films with opposite chirality. Sci. Rep. 8, 2361 (2018).

  34. 34.

    Eyrich, C. et al. Exchange stiffness in thin film Co alloys. J. Appl. Phys. 111, 07C919 (2012).

  35. 35.

    Perini, M. et al. Domain walls and Dzyaloshinskii–Moriya interaction in epitaxial Co/Ir(111) and Pt/Co/Ir(111). Phys. Rev. B 97, 184425 (2018).

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Acknowledgements

The authors acknowledge discussions with N. Jaouen, S. Stanescu and A. Hierro-Rodríguez, as well as experimental support from D. Sanz Hernández, A. Welbourne, P. Seem and I. Farrer. A.F.-P. acknowledges funding from an EPSRC Early Career Fellowship EP/M008517/1 and from the Winton Program for the Physics of Sustainability. E.V. acknowledges support from the Horizon 2020 research and innovation programme under grant agreement no. 665095 (MAGicSky), and D.P. and R.P.C. acknowledge from the Templeton World Charity Foundation. F.U. acknowledges support from the Erasmus Mobility programme.

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A.F.-P. designed and carried out the experiments, grew the samples, analysed the data, carried out the Monte Carlo macrospin simulations and wrote the manuscript. E.V. performed the analytical calculations, carried out the atomistic Monte Carlo simulations and analysed the data derived from them, and wrote the manuscript. F.U. grew samples and analysed data. R.M. contributed to the experimental characterization of the samples. All authors discussed and contributed to the interpretation of the results, as well as to the writing of the manuscript.

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Correspondence to Amalio Fernández-Pacheco or Elena Vedmedenko.

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Supplementary Notes 1–7, Supplementary Figs. 1–9, Supplementary references 1–15

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Fernández-Pacheco, A., Vedmedenko, E., Ummelen, F. et al. Symmetry-breaking interlayer Dzyaloshinskii–Moriya interactions in synthetic antiferromagnets. Nat. Mater. 18, 679–684 (2019). https://doi.org/10.1038/s41563-019-0386-4

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