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Control of spin–orbit torques through crystal symmetry in WTe2/ferromagnet bilayers

Nature Physics volume 13, pages 300305 (2017) | Download Citation


Recent discoveries regarding current-induced spin–orbit torques produced by heavy-metal/ferromagnet and topological-insulator/ferromagnet bilayers provide the potential for dramatically improved efficiency in the manipulation of magnetic devices. However, in experiments performed to date, spin–orbit torques have an important limitation—the component of torque that can compensate magnetic damping is required by symmetry to lie within the device plane. This means that spin–orbit torques can drive the most current-efficient type of magnetic reversal (antidamping switching) only for magnetic devices with in-plane anisotropy, not the devices with perpendicular magnetic anisotropy that are needed for high-density applications. Here we show experimentally that this state of affairs is not fundamental, but rather one can change the allowed symmetries of spin–orbit torques in spin-source/ferromagnet bilayer devices by using a spin-source material with low crystalline symmetry. We use WTe2, a transition-metal dichalcogenide whose surface crystal structure has only one mirror plane and no two-fold rotational invariance. Consistent with these symmetries, we generate an out-of-plane antidamping torque when current is applied along a low-symmetry axis of WTe2/Permalloy bilayers, but not when current is applied along a high-symmetry axis. Controlling spin–orbit torques by crystal symmetries in multilayer samples provides a new strategy for optimizing future magnetic technologies.

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  1. 1.

    , & Current-induced torques in magnetic materials. Nat. Mater. 11, 372–381 (2012).

  2. 2.

    , , , & Spin–orbit torque induced magnetization switching in nano-scale Ta/CoFeB/MgO. Appl. Phys. Lett. 107, 012401 (2015).

  3. 3.

    et al. Electric manipulation of spin relaxation using the spin Hall effect. Phys. Rev. Lett. 101, 036601 (2008).

  4. 4.

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

  5. 5.

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

  6. 6.

    , , & Spin-torque ferromagnetic resonance induced by the spin Hall effect. Phys. Rev. Lett. 106, 036601 (2011).

  7. 7.

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

  8. 8.

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

  9. 9.

    et al. Spin transfer torque devices utilizing the giant spin Hall effect of tungsten. Appl. Phys. Lett. 101, 122404 (2012).

  10. 10.

    et al. Layer thickness dependence of the current-induced effective field vector in Ta|CoFeB|MgO. Nat. Mater. 12, 240–245 (2013).

  11. 11.

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

  12. 12.

    , , , & Current-driven dynamics of chiral ferromagnetic domain walls. Nat. Mater. 12, 611–616 (2013).

  13. 13.

    , , & Chiral spin torque at magnetic domain walls. Nat. Nanotech. 8, 527–533 (2013).

  14. 14.

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

  15. 15.

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

  16. 16.

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

  17. 17.

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

  18. 18.

    Spin-current interaction with a monodomain magnetic body: a model study. Phys. Rev. B 62, 570–578 (2000).

  19. 19.

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

  20. 20.

    , & Current induced effective magnetic field and magnetization reversal in uniaxial anisotropy (Ga, Mn)As. Appl. Phys. Lett. 97, 222501 (2010).

  21. 21.

    et al. Spin–orbit-driven ferromagnetic resonance. Nat. Nanotech. 6, 413–417 (2011).

  22. 22.

    et al. An antidamping spin–orbit torque originating from the Berry curvature. Nat. Nanotech. 9, 211–217 (2014).

  23. 23.

    et al. Electrical switching of an antiferromagnet. Science 351, 587–590 (2016).

  24. 24.

    et al. Complementary spin-Hall and inverse spin-galvanic effect torques in a ferromagnet/semiconductor bilayer. Nat. Commun. 6, 6730 (2015).

  25. 25.

    et al. Large, non-saturating magnetoresistance in WTe2. Nature 514, 205–208 (2014).

  26. 26.

    et al. Signature of strong spin–orbital coupling in the large nonsaturating magnetoresistance material WTe2. Phys. Rev. Lett. 115, 166601 (2015).

  27. 27.

    et al. Quantum oscillations, thermoelectric coefficients, and the Fermi surface of semimetallic WTe2. Phys. Rev. Lett. 114, 176601 (2015).

  28. 28.

    et al. Role of spin–orbit coupling and evolution of the electronic structure of WTe2 under an external magnetic field. Phys. Rev. Lett. 92, 125152 (2015).

  29. 29.

    et al. Tuning magnetotransport in a compensated semimetal at the atomic scale. Nat. Commun. 6, 8892 (2015).

  30. 30.

    & The transition metal dichalcogenides discussion and interpretation of the observed optical, electrical and structural properties. Adv. Phys. 18, 193–335 (1969).

  31. 31.

    et al. Electronics and Electronics and optoelectronics of two-dimensional transition metal dichalcogenides. Nat. Nanotech. 7, 699–712 (2012).

  32. 32.

    et al. Research update: spin transfer torques in permalloy on monolayer MoS2. APL Mater. 4, 032302 (2016).

  33. 33.

    et al. Direct observation of spin-to-charge conversion in MoS2 monolayer with spin pumping. Preprint at (2015).

  34. 34.

    The crystal structures of WTe2 and high-temperature MoTe2. Acta Crystallogr. 20, 268–274 (1966).

  35. 35.

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

  36. 36.

    , & Spin-transfer torques generated by the anomalous Hall effect and anisotropic magnetoresistance. Phys. Rev. Appl. 3, 044001 (2015).

  37. 37.

    et al. Central role of domain wall depinning for perpendicular magnetization switching driven by spin torque from the spin Hall effect. Phys. Rev. B 89, 024418 (2014).

  38. 38.

    et al. Magnetization switching through spin-Hall-effect-induced chiral domain wall propagation. Phys. Rev. B 89, 104421 (2014).

  39. 39.

    et al. Ultrafast magnetization switching by spin–orbit torques. Appl. Phys. Lett. 105, 212402 (2014).

  40. 40.

    et al. Spin–orbit torque driven chiral magnetization reversal in ultrathin nanostructures. Phys. Rev. B 92, 144424 (2015).

  41. 41.

    et al. Perpendicular magnetization reversal in Pt/[Co/Ni]3/Al multilayers via the spin Hall effect of Pt. Appl. Phys. Lett. 108, 082406 (2016).

  42. 42.

    et al. Raman scattering investigation of large positive magnetoresistance material WTe2. Appl. Phys. Lett. 106, 081906 (2015).

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We thank N. D. Reynolds for experimental assistance, R. De Alba for help with the graphics, and G. D. Fuchs and P. G. Gowtham for comments on the manuscript. This work was supported by the National Science Foundation (DMR-1406333) and the Army Research Office (W911NF-15-1-0447). G.M.S. acknowledges support by a National Science Foundation Graduate Research Fellowship under Grant No. DGE-1144153. M.H.D.G. acknowledges support by the Netherlands Organization for Scientific Research (NWO 680-50-1311) and the Kavli Institute at Cornell for Nanoscale Science. This work made use of the NSF-supported Cornell Nanoscale Facility (ECCS-1542081), the Cornell Center for Materials Research Shared Facilities, which are supported through the NSF MRSEC Program (DMR-1120296), and the NSF-supported Platform for the Accelerated Realization, Analysis, and Discovery of Interface Materials (PARADIM) (DMR-1539918).

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Author notes

    • D. MacNeill
    •  & G. M. Stiehl

    These authors contributed equally to this work.


  1. Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA

    • D. MacNeill
    • , G. M. Stiehl
    • , M. H. D. Guimaraes
    •  & D. C. Ralph
  2. Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853, USA

    • M. H. D. Guimaraes
    • , J. Park
    •  & D. C. Ralph
  3. School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA

    • R. A. Buhrman
  4. Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA

    • J. Park


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D.M., G.M.S., M.H.D.G. and D.C.R. conceived the idea for the experiment. D.M. performed the sample fabrication. G.M.S. made the measurements. D.M. and G.M.S. performed the analysis with help from M.H.D.G., R.A.B., J.P. and D.C.R. D.M., G.M.S. and D.C.R. wrote the manuscript and all authors contributed to the final version.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to D. C. Ralph.

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