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
Access options
Subscribe to this journal
Receive 12 print issues and online access
$259.00 per year
only $21.58 per issue
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Chappert, C., Fert, A. & Nguyen Van Dau, F. The emergence of spin electronics in data storage. Nature Mater. 6, 813–823 (2007).
Slonczewski, J. C. Current-driven excitation of magnetic multilayers. J. Magn. Magn. Mater. 159, L1–L7 (1996).
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).
Dieny, B. et al. Spin-transfer effect and its use in spintronic components. Int. J. Nanotech. 7, 591–614 (2010).
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).
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).
Miron, I. M. et al. Perpendicular switching of a single ferromagnetic layer induced by in-plane current injection. Nature 476, 189–193 (2011).
Manchon, A. & Zhang, S. Theory of nonequilibrium intrinsic spin torque in a single nanomagnet. Phys. Rev. B 78, 212405 (2008).
Liu, L. et al. Spin–torque switching with the giant spin Hall effect of tantalum. Science 336, 555–558 (2012).
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).
Berger, L. Exchange interaction between ferromagnetic domain wall and electric current in very thin metallic films. J. Appl. Phys. 55, 1954–1956 (1984).
Klaui, M. et al. Domain wall motion induced by spin polarized currents in ferromagnetic ring structures. Appl. Phys. Lett. 83, 105–107 (2003).
Parkin, S. S. P., Hayashi, M. & Thomas, L. Magnetic domain-wall racetrack memory. Science 320, 190–194 (2008).
Miron, I. M. et al. Fast current-induced domain-wall motion controlled by the Rashba effect. Nature Mater. 10, 419–423 (2011).
Koyama, T. et al. Observation of the intrinsic pinning of a magnetic domain wall in a ferromagnetic nanowire. Nature Mater. 10, 194–197 (2011).
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).
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).
Thiaville, A. et al. Dynamics of Dzyaloshinskii domain walls in ultrathin magnetic films. Europhys. Lett. 100, 57002 (2012).
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).
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).
Garello, K. et al. Symmetry and magnitude of spin–orbit torques in ferromagnetic heterostructures. Nature Nanotech. 8, 587–593 (2013).
Qiu, X. et al. Spin–orbit–torque engineering via oxygen manipulation. Nature Nanotech. 10, 333–338 (2015).
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).
Fan, Y. et al. Magnetization switching through giant spin–orbit torque in a magnetically doped topological insulator heterostructure. Nature Mater. 13, 699–704 (2014).
Kim, J. et al. Layer thickness dependence of the current-induced effective field vector in Ta/CoFeB/MgO. Nature Mater. 12, 240–245 (2013).
Mellnik, A. R. et al. Spin–transfer torque generated by a topological insulator. Nature 511, 449–451 (2014).
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).
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
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
Ethics declarations
Competing interests
The authors declare no competing financial interests.
Supplementary information
Supplementary information
Supplementary information (PDF 1157 kb)
Rights and permissions
About this article
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
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/nnano.2015.252
This article is cited by
-
Room temperature energy-efficient spin-orbit torque switching in two-dimensional van der Waals Fe3GeTe2 induced by topological insulators
Nature Communications (2023)
-
Field-free spin-orbit torque switching assisted by in-plane unconventional spin torque in ultrathin [Pt/Co]N
Nature Communications (2023)
-
Field-free switching of perpendicular magnetization at room temperature using out-of-plane spins from TaIrTe4
Nature Electronics (2023)
-
Helicity dependent photoresistance measurement vs. beam-shift thermal gradient
Nature Communications (2022)
-
Effect of Chiral Damping on the dynamics of chiral domain walls and skyrmions
Nature Communications (2022)
