Current-induced magnetization switching in all-oxide heterostructures

Abstract

The electrical switching of magnetization through spin–orbit torque (SOT)1 holds promise for application in information technologies, such as low-power, non-volatile magnetic memory. Materials with strong spin–orbit coupling, such as heavy metals2,3,4 and topological insulators5,6, can convert a charge current into a spin current. The spin current can then execute a transfer torque on the magnetization of a neighbouring magnetic layer, usually a ferromagnetic metal like CoFeB, and reverse its magnetization. Here, we combine a ferromagnetic transition metal oxide7 with an oxide with strong spin–orbit coupling8 to demonstrate all-oxide SOT devices. We show current-induced magnetization switching in SrIrO3/SrRuO3 bilayer structures. By controlling the magnetocrystalline anisotropy of SrRuO3 on (001)- and (110)-oriented SrTiO3 (STO) substrates, we designed two types of SOT switching schemes. For the bilayer on the STO(001) substrate, a magnetic-field-free switching was achieved, which remained undisturbed even when the external magnetic field reached 100 mT. The charge-to-spin conversion efficiency for the bilayer on the STO(110) substrate ranged from 0.58 to 0.86, depending on the directionality of the current flow with respect to the crystalline symmetry. All-oxide SOT structures may help to realize field-free switching through a magnetocrystalline anisotropy design.

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Fig. 1: The SrIrO3/SrRuO3 bilayers on STO substrates.
Fig. 2: Magnetic anisotropy of the SrIrO3/SrRuO3 bilayer.
Fig. 3: Current-induced magnetization switching in SrIrO3/SrRuO3 bilayers.
Fig. 4: Harmonic Hall voltage analysis of the SrRuO3/SrIrO3 bilayer on a STO(110) substrate.

Data availability

The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.

References

  1. 1.

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

  2. 2.

    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 

  3. 3.

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

    CAS  Article  Google Scholar 

  4. 4.

    Zhu, L., Ralph, D. C. & Buhrman, R. A. Highly efficient spin-current generation by the spin Hall effect in Au1–xPtx. Phys. Rev. Appl. 10, 031001 (2018).

    CAS  Article  Google Scholar 

  5. 5.

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

    CAS  Article  Google Scholar 

  6. 6.

    Mahendra, D. C. et al. Room-temperature high spin–orbit torque due to quantum confinement in sputtered BixSe(1–x) films. Nat. Mater. 17, 800–807 (2018).

    Article  Google Scholar 

  7. 7.

    Koster, G. et al. Structure, physical properties, and applications of SrRuO3 thin films. Rev. Mod. Phys. 84, 253–298 (2012).

    CAS  Article  Google Scholar 

  8. 8.

    Patri, A. S., Hwang, K., Lee, H.-W. & Kim, Y. B. Theory of large intrinsic spin Hall effect in iridate semimetals. Sci. Rep. 8, 8052 (2018).

    Article  Google Scholar 

  9. 9.

    Sinova, J., Valenzuela, S. O., Wunderlich, J., Back, C. H. & Jungwirth, T. Spin Hall effects. Rev. Mod. Phys. 87, 1213–1260 (2015).

    Article  Google Scholar 

  10. 10.

    Yu, A. B. & Rashba, E. I. Oscillatory effects and the magnetic susceptibility of carriers in inversion layers. J. Phys. C 17, 6039–6045 (1984).

    Article  Google Scholar 

  11. 11.

    Guo, G. Y., Murakami, S., Chen, T. W. & Nagaosa, N. Intrinsic spin Hall effect in platinum: first-principles calculations. Phys. Rev. Lett. 100, 096401 (2008).

    CAS  Article  Google Scholar 

  12. 12.

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

    CAS  Article  Google Scholar 

  13. 13.

    Fukami, S., Zhang, C., Dutta Gupta, S., Kurenkov, A. & Ohno, H. Magnetization switching by spin–orbit torque in an antiferromagnet–ferromagnet bilayer system. Nat. Mater. 15, 535–541 (2016).

    CAS  Article  Google Scholar 

  14. 14.

    Oh, Y. W. et al. Field-free switching of perpendicular magnetization through spin–orbit torque in antiferromagnet/ferromagnet/oxide structures. Nat. Nanotechnol. 11, 878–884 (2016).

    CAS  Article  Google Scholar 

  15. 15.

    Hwang, H. Y. et al. Emergent phenomena at oxide interfaces. Nat. Mater. 11, 103–113 (2012).

    CAS  Article  Google Scholar 

  16. 16.

    Marshall, A. F. et al. Lorentz transmission electron microscope study of ferromagnetic domain walls in SrRuO3: statics, dynamics, and crystal structure correlation. J. Appl. Phys. 85, 4131–4140 (1999).

    CAS  Article  Google Scholar 

  17. 17.

    Jung, C. U., Yamada, H., Kawasaki, M. & Tokura, Y. Magnetic anisotropy control of SrRuO3 films by tunable epitaxial strain. Appl. Phys. Lett. 84, 2590–2592 (2004).

    CAS  Article  Google Scholar 

  18. 18.

    Schultz, M., Levy, S., Reiner, J. W. & Klein, L. Magnetic and transport properties of epitaxial films of SrRuO3 in the ultrathin limit. Phys. Rev. B 79, 125444 (2009).

    Article  Google Scholar 

  19. 19.

    Gan, Q., Rao, R. A., Eom, C. B., Wu, L. & Tsui, F. Lattice distortion and uniaxial magnetic anisotropy in single domain epitaxial (110) films of SrRuO3. J. Appl. Phys. 85, 5297–5299 (1999).

    CAS  Article  Google Scholar 

  20. 20.

    Liao, Z. et al. Controlled lateral anisotropy in correlated manganite heterostructures by interface-engineered oxygen octahedral coupling. Nat. Mater. 15, 425–431 (2016).

    CAS  Article  Google Scholar 

  21. 21.

    Lu, W. et al. Strain engineering of octahedral rotations and physical properties of SrRuO3 films. Sci. Rep. 5, 10245 (2015).

    Article  Google Scholar 

  22. 22.

    Lu, W., Yang, P., Song, W. D., Chow, G. M. & Chen, J. S. Control of oxygen octahedral rotations and physical properties in SrRuO3 films. Phys. Rev. B 88, 214115 (2013).

    Article  Google Scholar 

  23. 23.

    Gong, Y. et al. Band gap engineering and layer-by-layer mapping of selenium-doped molybdenum disulfide. Nano Lett. 14, 442–449 (2014).

    CAS  Article  Google Scholar 

  24. 24.

    Qin, Q., Song, W., He, S., Yang, P. & Chen, J. Magnetization reversal and magnetoresistance behavior of exchange coupled SrRuO3 bilayer. J. Phys. D Appl. Phys. 50, 215002 (2017).

    Article  Google Scholar 

  25. 25.

    Eason, K., Tan, S. G., Jalil, M. B. A. & Khoo, J. Y. Bistable perpendicular switching with in-plane spin polarization and without external fields. Phys. Lett. A 377, 2403–2407 (2013).

    CAS  Article  Google Scholar 

  26. 26.

    You, L. et al. Switching of perpendicularly polarized nanomagnets with spin–orbit torque without an external magnetic field by engineering a tilted anisotropy. Proc. Natl Acad. Sci. USA 112, 10310 (2015).

    CAS  Article  Google Scholar 

  27. 27.

    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 

  28. 28.

    Zhao, Z., Klemm Smith, A., Jamali, M. & Wang, J.-P. External-field-free spin Hall switching of perpendicular magnetic nanopillar with a dipole-coupled composite structure. Preprint at http://arXiv.org/abs/1603.09624 (2016).

  29. 29.

    Wang, X.et al. Current-driven magnetization switching in a van der Waals ferromagnet Fe3GeTe2. Preprint at http://arXiv.org/abs/eprintarXiv1902.05794 (2019).

  30. 30.

    Yoshimi, R. et al. Current-driven magnetization switching in ferromagnetic bulk Rashba semiconductor (Ge,Mn)Te. Sci. Adv. 4, eaat9989 (2018).

    CAS  Article  Google Scholar 

  31. 31.

    Hayashi, M., Kim, J., Yamanouchi, M. & Ohno, H. Quantitative characterization of the spin–orbit torque using harmonic Hall voltage measurements. Phys. Rev. B 89, 144425 (2014).

    Article  Google Scholar 

  32. 32.

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

    CAS  Article  Google Scholar 

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Acknowledgements

The research is supported by the Singapore National Research Foundation under CRP Award no. NRF-CRP10-2012-02 and the Singapore Ministry of Education MOE2018-T2-2-043 and MOE 2018-T2-1-019, AMEIRG18-0022 and A*STAR IAF-ICP 11801E0036. J.C. is a member of the Singapore Spintronics Consortium (SG-SPIN). C.L. acknowledges the financial support from the Lee Kuan Yew Postdoctoral Fellowship through the Singapore Ministry of Education Academic Research Fund Tier 1 (Grant no. R-284-000-158-114).

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L.L. and J.C. conceived and designed the experiments. L.L., W.Lin, Q.Q., Q.X., X.S., C.Z. and J.Y. performed the sample fabrication and experimental measurements. L.L, W.Lin, Q.Q., S.H., Z.L., W.Lu and X.Y. analysed the electrical transport data. C.L., M.L. and S.J.P. performed the STEM. L.L., W.Lin, Q.Q. and J.C. wrote the manuscript and all authors contributed to its final version.

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Correspondence to Jingsheng Chen.

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Peer review information: Nature Nanotechnology thanks Lior Klein and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary Information

Supplementary Figs. 1–16, Table 1 and Refs. 1–22.

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Liu, L., Qin, Q., Lin, W. et al. Current-induced magnetization switching in all-oxide heterostructures. Nat. Nanotechnol. 14, 939–944 (2019). https://doi.org/10.1038/s41565-019-0534-7

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