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.

Spin–orbit torque magnetization switching controlled by geometry

Abstract

Magnetization reversal by an electric current1,2,3,4,5,6,7,8,9 is essential for future magnetic data storage technology1, such as magnetic random access memories4. Typically, an electric current is injected into a pillar-shaped magnetic element, and switching relies on the transfer of spin momentum1,2,3,4 from a ferromagnetic reference layer (an approach known as spin–transfer torque). Recently, an alternative technique has emerged that uses spin–orbit torque (SOT) and allows the magnetization to be reversed without a polarizing layer by transferring angular momentum directly from the crystal lattice5,6,7,8,9. With spin–orbit torque, the current is no longer applied perpendicularly, but is in the plane of the magnetic thin film. Therefore, the current flow is no longer restricted to a single direction and can have any orientation within the film plane. Here, we use Kerr microscopy to examine spin–orbit torque-driven domain wall motion in Co/AlOx wires with different shapes and orientations on top of a current-carrying Pt layer. The displacement of the domain walls is found to be highly dependent on the angle between the direction of the current and domain wall motion, and asymmetric and nonlinear with respect to the current polarity. Using these insights, devices are fabricated in which magnetization switching is determined entirely by the geometry of the device.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.

$32.00

All prices are NET prices.

Figure 1: The geometric specificity of SOT with respect to STT.
Figure 2: Non-collinear domain wall motion.
Figure 3: Device geometry design.
Figure 4: Geometric magnetization reversal.

References

  1. Chappert, C., Fert, A. & Nguyen Van Dau, F. The emergence of spin electronics in data storage. Nature Mater. 6, 813–823 (2007).

    Article  CAS  Google Scholar 

  2. Slonczewski, J. C. Current-driven excitation of magnetic multilayers. J. Magn. Magn. Mater. 159, L1–L7 (1996).

    Article  Google Scholar 

  3. Myers, E. B., Ralph, D. C., Katine, J. A., Louie, R. N. & Buhrman, R. A. Current-induced switching of domains in magnetic multilayer devices. Science 285, 867–870 (1999).

    Article  CAS  Google Scholar 

  4. Dieny, B. et al. Spin-transfer effect and its use in spintronic components. Int. J. Nanotech. 7, 591–614 (2010).

    Article  CAS  Google Scholar 

  5. Chernyshov, A. et al. Evidence for reversible control of magnetization in a ferromagnetic material by means of spin–orbit magnetic field. Nature Phys. 5, 656–659 (2009).

    Article  CAS  Google Scholar 

  6. Miron, I. M. et al. Current-driven spin torque induced by the Rashba effect in a ferromagnetic metal layer. Nature Mater. 9, 230–233 (2010).

    Article  Google Scholar 

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

    Article  CAS  Google Scholar 

  8. Manchon, A. & Zhang, S. Theory of nonequilibrium intrinsic spin torque in a single nanomagnet. Phys. Rev. B 78, 212405 (2008).

    Article  Google Scholar 

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

    Article  CAS  Google Scholar 

  10. Rodmacq, B., Manchon, A., Ducruet, C., Auffret, S. & Dieny, B. Influence of thermal annealing on the perpendicular magnetic anisotropy of Pt/Co/AlOx trilayers. Phys. Rev. B 79, 024423 (2009).

    Article  Google Scholar 

  11. Berger, L. Exchange interaction between ferromagnetic domain wall and electric current in very thin metallic films. J. Appl. Phys. 55, 1954–1956 (1984).

    Article  CAS  Google Scholar 

  12. Klaui, M. et al. Domain wall motion induced by spin polarized currents in ferromagnetic ring structures. Appl. Phys. Lett. 83, 105–107 (2003).

    Article  CAS  Google Scholar 

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

    Article  CAS  Google Scholar 

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

    Article  CAS  Google Scholar 

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

    Article  CAS  Google Scholar 

  16. Boulle, O. et al. Domain wall tilting in the presence of the Dzyaloshinskii–Moriya interaction in out-of-plane magnetized magnetic nanotracks. Phys. Rev. Lett. 111, 217203 (2013).

    Article  CAS  Google Scholar 

  17. Ryu, K.-S. et al. Current induced tilting of domain walls in high velocity motion along perpendicularly magnetized micron-sized Co/Ni/Co racetracks. Appl. Phys. Express 5, 093006 (2012).

    Article  Google Scholar 

  18. Thiaville, A. et al. Dynamics of Dzyaloshinskii domain walls in ultrathin magnetic films. Europhys. Lett. 100, 57002 (2012).

    Article  Google Scholar 

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

    Article  CAS  Google Scholar 

  20. Emori, S., Bauer, U., Ahn, S. M., Martinez, E. & Beach, G. S. Current-driven dynamics of chiral ferromagnetic domain walls. Nature Mater. 12, 611–616 (2013).

    Article  CAS  Google Scholar 

  21. Garello, K. et al. Symmetry and magnitude of spin–orbit torques in ferromagnetic heterostructures. Nature Nanotech. 8, 587–593 (2013).

    Article  CAS  Google Scholar 

  22. Qiu, X. et al. Spin–orbit–torque engineering via oxygen manipulation. Nature Nanotech. 10, 333–338 (2015).

    Article  CAS  Google Scholar 

  23. Avci, C. A. et al. Field-like and anti-damping spin–orbit torques in as-grown and annealed Ta/CoFeB/MgO layers. Phys. Rev. B 89, 214419 (2014).

    Article  Google Scholar 

  24. Fan, Y. et al. Magnetization switching through giant spin–orbit torque in a magnetically doped topological insulator heterostructure. Nature Mater. 13, 699–704 (2014).

    Article  CAS  Google Scholar 

  25. Kim, J. et al. Layer thickness dependence of the current-induced effective field vector in Ta/CoFeB/MgO. Nature Mater. 12, 240–245 (2013).

    Article  CAS  Google Scholar 

  26. Mellnik, A. R. et al. Spin–transfer torque generated by a topological insulator. Nature 511, 449–451 (2014).

    Article  CAS  Google Scholar 

  27. Yu, G. et al. Switching of perpendicular magnetization by spin–orbit torques in the absence of external magnetic fields. Nature Nanotech. 9, 548–554 (2014).

    Article  CAS  Google Scholar 

Download references

Acknowledgements

This work was supported by the European Commission under the Seventh Framework Programme (grant nos. 318144, 2012-322369) and French Government Project ANR-11-BS10-0008. The devices were fabricated at Nanofab CNRS and the Plateforme de Technologique Amont in Grenoble.

Author information

Authors and Affiliations

Authors

Contributions

C.K.S., E.J., G.G. and I.M.M. planned the experiment. I.M.M., G.G., A.L. and S.A. fabricated the samples. C.K.S., E.J., S.P. and I.M.M. performed the experiments. C.K.S. and I.M.M. analysed the data and wrote the manuscript. All authors discussed the results and commented on the manuscript.

Corresponding author

Correspondence to Ioan Mihai Miron.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary information

Supplementary information (PDF 1157 kb)

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Safeer, C., Jué, E., Lopez, A. et al. Spin–orbit torque magnetization switching controlled by geometry. Nature Nanotech 11, 143–146 (2016). https://doi.org/10.1038/nnano.2015.252

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nnano.2015.252

This article is cited by

Search

Quick links

Find nanotechnology articles, nanomaterial data and patents all in one place. Visit Nano by Nature Research