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.

Room-temperature high spin–orbit torque due to quantum confinement in sputtered BixSe(1–x) films

Abstract

The spin–orbit torque (SOT) that arises from materials with large spin–orbit coupling promises a path for ultralow power and fast magnetic-based storage and computational devices. We investigated the SOT from magnetron-sputtered BixSe(1–x) thin films in BixSe(1–x)/Co20Fe60B20 heterostructures by using d.c. planar Hall and spin-torque ferromagnetic resonance (ST-FMR) methods. Remarkably, the spin torque efficiency (θS) was determined to be as large as 18.62 ± 0.13 and 8.67 ± 1.08 using the d.c. planar Hall and ST-FMR methods, respectively. Moreover, switching of the perpendicular CoFeB multilayers using the SOT from the BixSe(1–x) was observed at room temperature with a low critical magnetization switching current density of 4.3 × 105 A cm–2. Quantum transport simulations using a realistic sp3 tight-binding model suggests that the high SOT in sputtered BixSe(1–x) is due to the quantum confinement effect with a charge-to-spin conversion efficiency that enhances with reduced size and dimensionality. The demonstrated θS, ease of growth of the films on a silicon substrate and successful growth and switching of perpendicular CoFeB multilayers on BixSe(1–x) films provide an avenue for the use of BixSe(1–x) as a spin density generator in SOT-based memory and logic devices.

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.

Fig. 1: STEM and surface morphology characterization.
Fig. 2: Schematic diagram, experimental set-up, angle-dependent Hall resistance measurements and characterization of SOT.
Fig. 3: Effect of quantum confinement on spin accumulation.
Fig. 4: Current-induced magnetization switching in the BixSe(1–x)(4 nm)/Ta(0.5 nm)/CoFeB(0.6 nm)/Gd(1.2 nm)/CoFeB(1.1 nm) heterostructure.

References

  1. Hasan, M. Z. & Kane, C. L. Colloquium: topological insulators. Rev. Mod. Phys. 82, 3045–3067 (2010).

    Article  Google Scholar 

  2. Zhang, H. et al. Topological insulators in Bi2Se3, Bi2Te3 and Sb2Te3 with a single Dirac cone on the surface. Nat. Phys. 5, 438–442 (2009).

    Article  Google Scholar 

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

    Article  Google Scholar 

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

    Article  Google Scholar 

  5. Kondou, K. et al. Fermi-level-dependent charge-to-spin current conversion by Dirac surface states of topological insulators. Nat. Phys. 12, 1027–1032 (2016).

    Article  Google Scholar 

  6. Wang, Y. et al. Topological surface states originated spin–orbit torques in Bi2Se3. Phys. Rev. Lett. 114, 257202 (2015).

    Article  Google Scholar 

  7. Li, C. H. et al. Electrical detection of charge-current-induced spin polarization due to spin-momentum locking in Bi2Se3. Nat. Nanotech 9, 218–224 (2014).

    Article  Google Scholar 

  8. Ando, Y. et al. Electrical detection of the spin polarization due to charge flow in the surface state of the topological insulator Bi1.5Sb0.5Te1.7Se1.3. Nano Lett. 14, 6226–6230 (2014).

    Article  Google Scholar 

  9. Chen, Y. L. et al. Experimental realization of a three-dimensional topological insulator, Bi2Te3. Science 325, 178–180 (2009).

    Article  Google Scholar 

  10. Pan, Z.-H. et al. Electronic structure of the topological insulator Bi2Se3 using angle-resolved photoemission spectroscopy: evidence for a nearly full surface spin polarization. Phys. Rev. Lett. 106, 257004 (2011).

    Article  Google Scholar 

  11. Manchon, A. et al. Current-induced spin–orbit torques in ferromagnetic and antiferromagnetic systems. Preprint at http://arXiv.org/cond-mat.mes-hall/1801.09636 (2018).

  12. Jamali, M. et al. Giant spin pumping and inverse spin Hall effect in the presence of surface and bulk spin-orbit coupling of topological insulator Bi2Se3. Nano Lett. 15, 7126–7132 (2015).

    Article  Google Scholar 

  13. Shiomi, Y. et al. Spin–electricity conversion induced by spin injection into topological insulators. Phys. Rev. Lett. 113, 196601 (2014).

    Article  Google Scholar 

  14. Deorani, P. et al. Observation of inverse spin Hall effect in bismuth selenide. Phys. Rev. B 90, 94403 (2014).

    Article  Google Scholar 

  15. Rojas-Sánchez, J.-C. et al. Spin to charge conversion at room temperature by spin pumping into a new type of topological insulator: α-Sn films. Phys. Rev. Lett. 116, 96602 (2016).

    Article  Google Scholar 

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

    Article  Google Scholar 

  17. Manchon, A. & Zhang, S. Theory of spin torque due to spin-orbit coupling. Phys. Rev. B 79, 94422 (2009).

    Article  Google Scholar 

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

    Article  Google Scholar 

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

    Article  Google Scholar 

  20. Manchon, A., Koo, H. C., Nitta, J., Frolov, S. M. & Duine, R. A. New perspectives for Rashba spin–orbit coupling. Nat. Mater. 14, 871–882 (2015).

    Article  Google Scholar 

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

    Article  Google Scholar 

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

    Article  Google Scholar 

  23. Brataas, A. & Hals, K. M. D. Spin–orbit torques in action. Nat. Nanotechnol. 9, 86–88 (2014).

    Article  Google Scholar 

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

    Article  Google Scholar 

  25. Manipatruni, S., Nikonov, D. E. & Young, I. A. Energy-delay performance of giant spin Hall effect switching for dense magnetic memory. Appl. Phys. Express 7, 103001 (2014).

    Article  Google Scholar 

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

    Article  Google Scholar 

  27. Zhao, Z., Jamali, M., Smith, A. K. & Wang, J. P. Spin Hall switching of the magnetization in Ta/TbFeCo structures with bulk perpendicular anisotropy. Appl. Phys. Lett. 106, 132404 (2015).

    Article  Google Scholar 

  28. Hao, Q. & Xiao, G. Giant spin Hall effect and switching induced by spin-transfer torque in a W/Co40Fe40B20/MgO structure with perpendicular magnetic anisotropy. Phys. Rev. Appl. 3, 34009 (2015).

    Article  Google Scholar 

  29. 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, 96602 (2012).

    Article  Google Scholar 

  30. Han, J. et al. Room-temperature spin–orbit torque switching induced by a topological insulator. Phys. Rev. Lett. 119, 77702 (2017).

    Article  Google Scholar 

  31. Wang, Y. et al. Room temperature magnetization switching in topological insulator–ferromagnet heterostructures by spin–orbit torques. Nat. Commun. 8, 1364 (2017).

    Article  Google Scholar 

  32. Kawaguchi, M. et al. Current-induced effective fields detected by magnetotransport measurements. Appl. Phys. Express 6, 113002 (2013).

    Article  Google Scholar 

  33. Liu, L., Moriyama, T., Ralph, D. C. & Buhrman, R. A. Spin-torque ferromagnetic resonance induced by the spin Hall effect. Phys. Rev. Lett. 106, 36601 (2011).

    Article  Google Scholar 

  34. Xu, W. J. et al. Scaling law of anomalous Hall effect in Fe/Cu bilayers. Eur. Phys. J. B 65, 233–237 (2008).

    Article  Google Scholar 

  35. Şahin, C. & Flatte, M. E. Tunable giant spin Hall conductivities in a strong spin–orbit semimetal: Bi1–xSbx. Phys. Rev. Lett. 114, 107201 (2015).

    Article  Google Scholar 

  36. Zhang, W., Han, W., Jiang, X., Yang, S.-H. & Parkin, S. S. P. Role of transparency of platinum–ferromagnet interfaces in determining the intrinsic magnitude of the spin Hall effect. Nat. Phys. 11, 496–503 (2015).

    Article  Google Scholar 

  37. Ashcroft, N. W. & Mermin, N. D. Solid State Physics (Brooks-Cole, Grove, 1976).

  38. Kobayashi, K. Electron transmission through atomic steps of Bi2Se3 and Bi2Te3 surfaces. Phys. Rev. B 84, 205424 (2011).

    Article  Google Scholar 

  39. Edelstein, V. M. Spin polarization of conduction electrons induced by electric current in two-dimensional asymmetric electron systems. Solid State Commun. 73, 233–235 (1990).

    Article  Google Scholar 

  40. Ndiaye, P. B. et al. Dirac spin–orbit torques and charge pumping at the surface of topological insulators. Phys. Rev. B 96, 14408 (2017).

    Article  Google Scholar 

  41. Ghosh, S. & Manchon, A. Spin–orbit torque in a three-dimensional topological insulator–ferromagnet heterostructure: crossover between bulk and surface transport. Phys. Rev. B 97, 134402 (2018).

    Article  Google Scholar 

  42. Fischer, M. H., Vaezi, A., Manchon, A. & Kim, E.-A. Spin-torque generation in topological insulator based heterostructures. Phys. Rev. B 93, 125303 (2016).

    Article  Google Scholar 

  43. Mahfouzi, F., Nikoli, B. K. & Kioussis, N. Antidamping spin–orbit torque driven by spin–flip reflection mechanism on the surface of a topological insulator: a time-dependent nonequilibrium Green function approach. Phys. Rev. B 93, 115419 (2016).

    Article  Google Scholar 

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

    Article  Google Scholar 

  45. Bahramy, M. S. et al. Emergent quantum confinement at topological insulator surfaces. Nat. Commun. 3, 1159 (2012).

    Article  Google Scholar 

  46. Avci, C. O. et al. Interplay of spin–orbit torque and thermoelectric effects in ferromagnet/normal-metal bilayers. Phys. Rev. B 90, 224427 (2014).

    Article  Google Scholar 

  47. Pai, C.-F., Mann, M., Tan, A. J. & Beach, G. S. D. Determination of spin torque efficiencies in heterostructures with perpendicular magnetic anisotropy. Phys. Rev. B 93, 144409 (2016).

    Article  Google Scholar 

  48. Cao, J. et al. Spin–orbit torques induced magnetization reversal through asymmetric domain wall propagation in Ta/CoFeB/MgO structures. Sci. Rep. 8, 1355 (2018).

    Article  Google Scholar 

  49. Rojas-Sánchez, J.-C. et al. Spin pumping and inverse spin Hall effect in platinum: the essential role of spin-memory loss at metallic interfaces. Phys. Rev. Lett. 112, 106602 (2014).

    Article  Google Scholar 

  50. Avci, C. O. et al. Current-induced switching in a magnetic insulator. Nat. Mater. 16, 309–314 (2016).

    Article  Google Scholar 

  51. Li, P. et al. Spin–orbit torque-assisted switching in magnetic insulator thin films with perpendicular magnetic anisotropy. Nat. Commun. 7, 12688 (2016).

    Article  Google Scholar 

  52. Agarwala, A. & Shenoy, V. B. Topological insulators in amorphous systems. Phys. Rev. Lett. 118, 236402 (2017).

    Article  Google Scholar 

  53. Banerjee, A. et al. Granular topological insulators. Nanoscale 9, 6755 (2017).

    Article  Google Scholar 

  54. Datta, S. Electronic Transport in Mesoscopic Systems (Cambridge Univ. Press, Cambridge, 1995).

Download references

Acknowledgements

We thank P. Crowell for proofreading the manuscript and M. Kawaguchi for helpful discussions on data analysis. We also thank T. Peterson and G. Stecklein for their help with the PPMS measurements. This work was supported by C-SPIN, one of six STARnet programme research centres. This work utilized (1) the College of Science and Engineering (CSE) Characterization Facility, University of Minnesota (UM), supported in part by the NSF through the UMN MRSEC programme (no. DMR-1420013), and (2) the CSE Minnesota Nano Center, UM, supported in part by the NSF through the NNIN programme. A.M. was supported by the King Abdullah University of Science and Technology (KAUST).

Author information

Authors and Affiliations

Authors

Contributions

J.P.W., M.DC. and M.J. designed the experiments. J.-Y.C., M.J. and D.Z. grew the samples. M.DC., M.J., Z.Z., H.L., D.Z. and Y.L. designed the experimental set-up. M.DC., H.L. and Z.Z. performed the fabrication of the devices and electrical measurements. J.P.W. proposed the study of the grain-dependent quantum confinement effect on the sputtered BixSe(1–x) films. R.G., T.L. and A.M. carried out the theoretical modelling. D.R.H. and K.A.M. performed the STEM. M.DC., D.Z. and P.Q. did data analysis. M.DC. and J.P.W. wrote the manuscript, and all the authors discussed the results, contributed to the draft of the manuscript and commented on the final version. J.P.W. coordinated the overall project.

Corresponding author

Correspondence to Jian-Ping Wang.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary sections 1–11, Supplementary Table 1, Supplementary Figures 1–10, Supplementary References 1–15

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

DC, M., Grassi, R., Chen, JY. et al. Room-temperature high spin–orbit torque due to quantum confinement in sputtered BixSe(1–x) films. Nature Mater 17, 800–807 (2018). https://doi.org/10.1038/s41563-018-0136-z

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41563-018-0136-z

This article is cited by

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