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Tunable room-temperature magnetic skyrmions in Ir/Fe/Co/Pt multilayers

Nature Materials volume 16, pages 898–904 (2017)Cite this article

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Abstract

Magnetic skyrmions are nanoscale topological spin structures offering great promise for next-generation information storage technologies. The recent discovery of sub-100-nm room-temperature (RT) skyrmions in several multilayer films has triggered vigorous efforts to modulate their physical properties for their use in devices. Here we present a tunable RT skyrmion platform based on multilayer stacks of Ir/Fe/Co/Pt, which we study using X-ray microscopy, magnetic force microscopy and Hall transport techniques. By varying the ferromagnetic layer composition, we can tailor the magnetic interactions governing skyrmion properties, thereby tuning their thermodynamic stability parameter by an order of magnitude. The skyrmions exhibit a smooth crossover between isolated (metastable) and disordered lattice configurations across samples, while their size and density can be tuned by factors of two and ten, respectively. We thus establish a platform for investigating functional sub-50-nm RT skyrmions, pointing towards the development of skyrmion-based memory devices.

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Figure 1: DMI enhancement in Ir/Fe/Co/Pt stacks.
Figure 2: Magnetic microscopy of RT skyrmions.
Figure 4: Modulating magnetic interactions with Fe/Co composition.
Figure 3: Topological Hall effect (THE) from RT skyrmions.
Figure 5: Tuning skyrmion stability with Fe/Co composition.
Figure 6: Tuning skyrmion properties with Fe/Co composition.

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References

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

    Article  CAS  Google Scholar 

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

    Article  CAS  Google Scholar 

  3. Bogdanov, A. & Hubert, A. Thermodynamically stable magnetic vortex states in magnetic crystals. J. Magn. Magn. Mater. 138, 255–269 (1994).

    Article  CAS  Google Scholar 

  4. Rößler, U. K., Bogdanov, A. N. & Pfleiderer, C. Spontaneous skyrmion ground states in magnetic metals. Nature 442, 797–801 (2006).

    Article  Google Scholar 

  5. Mühlbauer, S. et al. Skyrmion lattice in a chiral magnet. Science 323, 915–919 (2009).

    Article  Google Scholar 

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

    Article  CAS  Google Scholar 

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

    Article  CAS  Google Scholar 

  8. Fert, A., Cros, V. & Sampaio, J. Skyrmions on the track. Nat. Nanotech. 8, 152–156 (2013).

    Article  CAS  Google Scholar 

  9. Sampaio, J., Cros, V., Rohart, S., Thiaville, A. & Fert, A. Nucleation, stability and current-induced motion of isolated magnetic skyrmions in nanostructures. Nat. Nanotech. 8, 839–844 (2013).

    Article  CAS  Google Scholar 

  10. Hagemeister, J., Romming, N., von Bergmann, K., Vedmedenko, E. Y. & Wiesendanger, R. Stability of single skyrmionic bits. Nat. Commun. 6, 8455 (2015).

    Article  CAS  Google Scholar 

  11. Heinze, S. et al. Spontaneous atomic-scale magnetic skyrmion lattice in two dimensions. Nat. Phys. 7, 713–718 (2011).

    Article  CAS  Google Scholar 

  12. Romming, N. et al. Writing and deleting single magnetic skyrmions. Science 341, 636–639 (2013).

    Article  CAS  Google Scholar 

  13. Schulz, T. et al. Emergent electrodynamics of skyrmions in a chiral magnet. Nat. Phys. 8, 301–304 (2012).

    Article  CAS  Google Scholar 

  14. Fert, A. Magnetic and transport properties of metallic multilayers. Mater. Sci. Forum 59–60, 439–480 (1990).

    Google Scholar 

  15. Bode, M. et al. Chiral magnetic order at surfaces driven by inversion asymmetry. Nature 447, 190–193 (2007).

    Article  CAS  Google Scholar 

  16. Soumyanarayanan, A., Reyren, N., Fert, A. & Panagopoulos, C. Emergent phenomena induced by spin-orbit coupling at surfaces and interfaces. Nature 539, 509–517 (2016).

    Article  CAS  Google Scholar 

  17. Heide, M., Bihlmayer, G. & Blügel, S. Dzyaloshinskii–Moriya interaction accounting for the orientation of magnetic domains in ultrathin films: Fe/W(110). Phys. Rev. B 78, 140403 (2008).

    Article  Google Scholar 

  18. Cho, J. et al. Thickness dependence of the interfacial Dzyaloshinskii–Moriya interaction in inversion symmetry broken systems. Nat. Commun. 6, 7635 (2015).

    Article  Google Scholar 

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

    Article  Google Scholar 

  20. 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).

    Article  Google Scholar 

  21. Moreau-Luchaire, C. et al. Additive interfacial chiral interaction in multilayers for stabilization of small individual skyrmions at room temperature. Nat. Nanotech. 11, 444–448 (2016).

    Article  CAS  Google Scholar 

  22. 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).

    Article  CAS  Google Scholar 

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

    Article  CAS  Google Scholar 

  24. Chen, G., Mascaraque, A., N’Diaye, A. T. & Schmid, A. K. Room temperature skyrmion ground state stabilized through interlayer exchange coupling. Appl. Phys. Lett. 106, 242404 (2015).

    Article  Google Scholar 

  25. Nandy, A. K., Kiselev, N. S. & Blügel, S. Interlayer exchange coupling: a general scheme turning chiral magnets into magnetic multilayers carrying atomic-scale skyrmions. Phys. Rev. Lett. 116, 177202 (2016).

    Article  Google Scholar 

  26. Jiang, W. et al. Blowing magnetic skyrmion bubbles. Science 349, 283–286 (2015).

    Article  CAS  Google Scholar 

  27. Büttner, F. et al. Dynamics and inertia of skyrmionic spin structures. Nat. Phys. 11, 225–228 (2015).

    Google Scholar 

  28. Kiselev, N. S., Bogdanov, A. N., Schäfer, R. & Rößler, U. K. Chiral skyrmions in thin magnetic films: new objects for magnetic storage technologies? J. Phys. D 44, 392001 (2011).

    Article  Google Scholar 

  29. Rohart, S. & Thiaville, A. Skyrmion confinement in ultrathin film nanostructures in the presence of Dzyaloshinskii–Moriya interaction. Phys. Rev. B 88, 184422 (2013).

    Article  Google Scholar 

  30. Leonov, A. O. et al. The properties of isolated chiral skyrmions in thin magnetic films. New J. Phys. 18, 065003 (2016).

    Article  Google Scholar 

  31. Tomasello, R. et al. A strategy for the design of skyrmion racetrack memories. Sci. Rep. 4, 6784 (2014).

    Article  CAS  Google Scholar 

  32. Zhang, X., Zhou, Y., Ezawa, M., Zhao, G. P. & Zhao, W. Magnetic skyrmion transistor: skyrmion motion in a voltage-gated nanotrack. Sci. Rep. 5, 11369 (2015).

    Article  Google Scholar 

  33. Neubauer, A. et al. Topological Hall effect in the A phase of MnSi. Phys. Rev. Lett. 102, 186602 (2009).

    Article  CAS  Google Scholar 

  34. Raičević, I. et al. Skyrmions in a doped antiferromagnet. Phys. Rev. Lett. 106, 227206 (2011).

    Article  Google Scholar 

  35. Porter, N. A., Gartside, J. C. & Marrows, C. H. Scattering mechanisms in textured FeGe thin films: magnetoresistance and the anomalous Hall effect. Phys. Rev. B 90, 024403 (2014).

    Article  Google Scholar 

  36. Milde, P. et al. Unwinding of a skyrmion lattice by magnetic monopoles. Science 340, 1076–1080 (2013).

    Article  CAS  Google Scholar 

  37. Dupé, B., Bihlmayer, G., Böttcher, M., Blügel, S. & Heinze, S. Engineering skyrmions in transition-metal multilayers for spintronics. Nat. Commun. 7, 11779 (2016).

    Article  Google Scholar 

  38. Yang, H., Boulle, O., Cros, V., Fert, A. & Chshiev, M. Controlling Dzyaloshinskii–Moriya interaction via chirality dependent layer stacking, insulator capping and electric field. Preprint at http://arxiv.org/abs/1603.01847 (2016).

  39. Johnson, M. T., Bloemen, P. J. H., Broeder, F. J. a. D. & Vries, J. J. D. Magnetic anisotropy in metallic multilayers. Rep. Prog. Phys. 59, 1409–1458 (1999).

    Article  Google Scholar 

  40. Nagaosa, N., Onoda, S., MacDonald, A. H. & Ong, N. P. Anomalous Hall effect. Rev. Mod. Phys. 82, 1539–1592 (2010).

    Article  Google Scholar 

  41. Huang, S. X. & Chien, C. L. Extended skyrmion phase in epitaxial FeGe(111) thin films. Phys. Rev. Lett. 108, 267201 (2012).

    Article  CAS  Google Scholar 

  42. Matsuno, J. et al. Interface-driven topological Hall effect in SrRuO3–SrIrO3 bilayer. Sci. Adv. 2, e1600304 (2016).

    Article  Google Scholar 

  43. Song, C.-L. et al. Dopant clustering, electronic inhomogeneity, and vortex pinning in iron-based superconductors. Phys. Rev. B 87, 214519 (2013).

    Article  Google Scholar 

  44. Parkin, S. S. P., Hayashi, M. & Thomas, L. Magnetic domain-wall racetrack memory. Science 320, 190–194 (2008).

    Article  CAS  Google Scholar 

  45. Kang, W. et al. Voltage controlled magnetic skyrmion motion for racetrack memory. Sci. Rep. 6, 23164 (2016).

    Article  CAS  Google Scholar 

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

    Article  Google Scholar 

  47. Malozemoff, A. P. & Slonczewski, J. C. Magnetic Domain Walls in Bubble Materials 1st edn (Academic, 1979).

    Google Scholar 

Download references

Acknowledgements

We acknowledge K. Masgrau, S. He and B. Satywali for experimental inputs, W. S. Lew for allowing us to access his instruments, and P. Fischer, O. Auslaender and A. Fert for insightful discussions. We also acknowledge the support of the A*STAR Computational Resource Center (A*CRC), Singapore and the National Supercomputing Centre (NSCC), Singapore for performing computational work. This work was supported by the Singapore Ministry of Education (MoE), Academic Research Fund Tier 2 (Ref. No. MOE2014-T2-1-050), the National Research Foundation (NRF) of Singapore, NRF - Investigatorship (Ref. No.: NRF-NRFI2015-04), and the A*STAR Pharos Fund (Ref. No. 1527400026) of Singapore. M.Y.I. acknowledges support from Leading Foreign Research Institute Recruitment Program through the National Research Foundation (NRF) of Korea funded by the Ministry of Education, Science and Technology (MEST) (2012K1A4A3053565) and by the DGIST R&D programme of the Ministry of Science, ICT and future Planning (17-BT-02). The work at ALS was supported by the Director, Office of Science, Office of Basic Energy Sciences, Scientific User Facilities Division of the US Department of Energy under Contract No. DE-AC02-05CH11231.

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Author notes

  1. A. L. Gonzalez Oyarce

    Present address: Institute of High Performance Computing, 1 Fusionopolis Way, 138632, Singapore

  2. Anthony K. C. Tan

    Present address: Data Storage Institute, 2 Fusionopolis Way, 138634, Singapore

Authors and Affiliations

  1. Data Storage Institute, 2 Fusionopolis Way, 138634, Singapore

    Anjan Soumyanarayanan, A. L. Gonzalez Oyarce, Pin Ho, M. Tran & F. Ernult

  2. Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371, Singapore

    Anjan Soumyanarayanan, M. Raju, Anthony K. C. Tan, A. P. Petrović & C. Panagopoulos

  3. Center for X-ray Optics, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, USA

    Mi-Young Im

  4. Department of Emerging Materials Science, DGIST, Daegu, 42988, Korea

    Mi-Young Im

  5. Institute of High Performance Computing, 1 Fusionopolis Way, 138632, Singapore

    K. H. Khoo & C. K. Gan

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Contributions

A.S., M.T., F.E. and C.P. designed and initiated the research. M.R. deposited the films, and characterized them with A.S. M.Y.I. conducted the MTXM experiments. A.K.C.T. performed the MFM experiments and analysed the imaging data with A.S., and P.H. validated the MFM results. M.R. and A.P.P. performed transport experiments and analysed the data with A.S. A.L.G.O. performed micromagnetic simulations. K.H.K. and C.K.G. carried out the DFT calculations. A.S. and C.P. coordinated the project and wrote the manuscript. All authors discussed the results and provided inputs to the manuscript.

Corresponding authors

Correspondence to Anjan Soumyanarayanan or C. Panagopoulos.

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Soumyanarayanan, A., Raju, M., Gonzalez Oyarce, A. et al. Tunable room-temperature magnetic skyrmions in Ir/Fe/Co/Pt multilayers. Nature Mater 16, 898–904 (2017). https://doi.org/10.1038/nmat4934

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