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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The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.
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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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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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DOI: https://doi.org/10.1038/s41565-019-0534-7
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