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.

Current-driven dynamics of chiral ferromagnetic domain walls

Abstract

In most ferromagnets the magnetization rotates from one domain to the next with no preferred handedness. However, broken inversion symmetry can lift the chiral degeneracy, leading to topologically rich spin textures such as spin spirals1,2 and skyrmions3,4,5 through the Dzyaloshinskii–Moriya interaction6 (DMI). Here we show that in ultrathin metallic ferromagnets sandwiched between a heavy metal and an oxide, the DMI stabilizes chiral domain walls2,7 (DWs) whose spin texture enables extremely efficient current-driven motion8,9,10,11. We show that spin torque from the spin Hall effect12,13,14,15 drives DWs in opposite directions in Pt/CoFe/MgO and Ta/CoFe/MgO, which can be explained only if the DWs assume a Néel configuration7,16 with left-handed chirality. We directly confirm the DW chirality and rigidity by examining current-driven DW dynamics with magnetic fields applied perpendicular and parallel to the spin spiral. This work resolves the origin of controversial experimental results10,17,18 and highlights a new path towards interfacial design of spintronic devices.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

Figure 1: Effect of current on DW motion.
Figure 2: Current-induced switching under a constant in-plane longitudinal field.
Figure 3: Current-induced effective fields.
Figure 4: Current-driven dynamics of chiral Néel DWs.

References

  1. 1

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

    CAS  Article  Google Scholar 

  2. 2

    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 

  3. 3

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

    CAS  Article  Google Scholar 

  4. 4

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

    CAS  Article  Google Scholar 

  5. 5

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

    CAS  Article  Google Scholar 

  6. 6

    Moriya, T. New mechanism of anisotropic superexchange interaction. Phys. Rev. Lett. 4, 228–230 (1960).

    CAS  Article  Google Scholar 

  7. 7

    Thiaville, A., Rohart, S., Jué, É., Cros, V. & Fert, A. Dynamics of Dzyaloshinskii domain walls in ultrathin magnetic films. Europhys. Lett. 100, 57002 (2012).

    Article  Google Scholar 

  8. 8

    Moore, T. A. et al. High domain wall velocities induced by current in ultrathin Pt/Co/AlOx wires with perpendicular magnetic anisotropy. Appl. Phys. Lett. 93, 262504 (2008).

    Article  Google Scholar 

  9. 9

    Miron, I. M. et al. Domain wall spin torquemeter. Phys. Rev. Lett. 102, 137202 (2009).

    CAS  Article  Google Scholar 

  10. 10

    Miron, I. M. et al. Fast current-induced domain-wall motion controlled by the Rashba effect. Nature Mater. 10, 419–423 (2011).

    CAS  Article  Google Scholar 

  11. 11

    Emori, S., Bono, D. C. & Beach, G. S. D. Interfacial current-induced torques in Pt/Co/GdOx. Appl. Phys. Lett. 101, 042405 (2012).

    Article  Google Scholar 

  12. 12

    Liu, L., Lee, O. J., Gudmundsen, T. J., Ralph, D. C. & Buhrman, R. A. Current-induced switching of perpendicularly magnetized magnetic layers using spin torque from the spin Hall effect. Phys. Rev. Lett. 109, 096602 (2012).

    Article  Google Scholar 

  13. 13

    Liu, L. et al. Spin-torque switching with the giant spin Hall effect of tantalum. Science 336, 555–558 (2012).

    CAS  Article  Google Scholar 

  14. 14

    Pai, C-F. et al. Spin transfer torque devices using the giant spin Hall effect of tungsten. Appl. Phys. Lett. 101, 122404 (2012).

    Article  Google Scholar 

  15. 15

    Haazen, P. P. J. et al. Domain wall depinning governed by the spin Hall effect. Nature Mater. 12, 299–303 (2013).

    CAS  Article  Google Scholar 

  16. 16

    Khvalkovskiy, A. V. et al. Matching domain-wall configuration and spin–orbit torques for efficient domain-wall motion. Phys. Rev. B 87, 020402 (2013).

    Article  Google Scholar 

  17. 17

    Miron, I. M. et al. Current-driven spin torque induced by the Rashba effect in a ferromagnetic metal layer. Nature Mater. 9, 230–234 (2010).

    Article  Google Scholar 

  18. 18

    Miron, I. M. et al. Perpendicular switching of a single ferromagnetic layer induced by in-plane current injection. Nature 476, 189–193 (2011).

    CAS  Article  Google Scholar 

  19. 19

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

    CAS  Article  Google Scholar 

  20. 20

    Allwood, D. A. et al. Magnetic domain-wall logic. Science 309, 1688–1692 (2005).

    CAS  Article  Google Scholar 

  21. 21

    Currivan, J., Jang, Y., Mascaro, M. D., Baldo, M. A. & Ross, C. A. Low energy magnetic domain wall Logic in short, narrow, ferromagnetic wires. IEEE Magn. Lett. 3, 3000104 (2012).

    Article  Google Scholar 

  22. 22

    Pi, U. H. et al. Tilting of the spin orientation induced by Rashba effect in ferromagnetic metal layer. Appl. Phys. Lett. 97, 162507 (2010).

    Article  Google Scholar 

  23. 23

    Suzuki, T. et al. Current-induced effective field in perpendicularly magnetized Ta/CoFeB/MgO wire. Appl. Phys. Lett. 98, 142505 (2011).

    Article  Google Scholar 

  24. 24

    Thiaville, A., Nakatani, Y., Miltat, J. & Suzuki, Y. Micromagnetic understanding of current-driven domain wall motion in patterned nanowires. Europhys. Lett. 69, 990–996 (2005).

    CAS  Article  Google Scholar 

  25. 25

    Cormier, M. et al. Effect of electrical current pulses on domain walls in Pt/Co/Pt nanotracks with out-of-plane anisotropy: Spin transfer torque versus Joule heating. Phys. Rev. B 81, 024407 (2010).

    Article  Google Scholar 

  26. 26

    Wang, X. & Manchon, A. diffusive spin dynamics in ferromagnetic thin films with a Rashba interaction. Phys. Rev. Lett. 108, 117201 (2012).

    Article  Google Scholar 

  27. 27

    Kim, K-W., Seo, S-M., Ryu, J., Lee, K-J. & Lee, H-W. Magnetization dynamics induced by in-plane currents in ultrathin magnetic nanostructures with Rashba spin–orbit coupling. Phys. Rev. B 85, 180404 (2012).

    Article  Google Scholar 

  28. 28

    Koyama, T. et al. Observation of the intrinsic pinning of a magnetic domain wall in a ferromagnetic nanowire. Nature Mater. 10, 194–197 (2011).

    CAS  Article  Google Scholar 

  29. 29

    Martinez, E. The stochastic nature of the domain wall motion along high perpendicular anisotropy strips with surface roughness. J. Phys. Condens. Matter 24, 024206 (2012).

    Article  Google Scholar 

  30. 30

    Kim, J. et al. Layer thickness dependence of the current-induced effective field vector in Ta|CoFeB|MgO. Nature Mater. 12, 240–245 (2012).

    Article  Google Scholar 

Download references

Acknowledgements

This work was supported in part by the National Science Foundation under NSF-ECCS-1128439. Technical support from D. Bono is gratefully acknowledged. Devices were fabricated using instruments in the MIT Nanostructures Laboratory, the Scanning Electron-Beam Lithography facility at the Research Laboratory of Electronics, and the Center for Materials Science and Engineering at MIT. S.E. acknowledges financial support by the NSF Graduate Research Fellowship Program. The work by E.M. was supported by projects MAT2011-28532-C03-01 from the Spanish government and SA163A12 from Junta de Castilla y Leon.

Author information

Affiliations

Authors

Contributions

G.S.D.B. proposed and supervised the study. S.E. and G.S.D.B. designed the experiments. S.E. and U.B. built the measurement set-ups with assistance from G.S.D.B. S-M.A. developed and deposited the Ta/CoFe/MgO and Pt/CoFe/MgO films. S.E. carried out the lithographic steps and performed all measurements. E.M. performed the modelling and wrote the corresponding text. S.E. analysed the data. S.E. and G.S.D.B. wrote the manuscript with assistance from U.B. All authors discussed the results and commented on the manuscript.

Corresponding author

Correspondence to Geoffrey S. D. Beach.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

Supplementary Information (PDF 2097 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Emori, S., Bauer, U., Ahn, SM. et al. Current-driven dynamics of chiral ferromagnetic domain walls. Nature Mater 12, 611–616 (2013). https://doi.org/10.1038/nmat3675

Download citation

Further reading

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