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Switching of perpendicular magnetization by spin–orbit torques in the absence of external magnetic fields

Nature Nanotechnology volume 9, pages 548554 (2014) | Download Citation

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Abstract

Magnetization switching by current-induced spin–orbit torques is of great interest due to its potential applications in ultralow-power memory and logic devices. The switching of ferromagnets with perpendicular magnetization is of particular technological relevance. However, in such materials, the presence of an in-plane external magnetic field is typically required to assist spin–orbit torque-driven switching and this is an obstacle for practical applications. Here, we report the switching of out-of-plane magnetized Ta/Co20Fe60B20/TaOx structures by spin–orbit torques driven by in-plane currents, without the need for any external magnetic fields. This is achieved by introducing a lateral structural asymmetry into our devices, which gives rise to a new field-like spin–orbit torque when in-plane current flows in these structures. The direction of the current-induced effective field corresponding to this field-like spin–orbit torque is out-of-plane, facilitating the switching of perpendicular magnets.

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Acknowledgements

This work was partially supported by the Defense Advanced Research Projects Agency (DARPA) programme on Nonvolatile Logic (NVL) and in part by the National Science Foundation Nanosystems Engineering Research Center for Translational Applications of Nanoscale Multiferroic Systems (TANMS). This work was also supported in part by the Function Accelerated nanoMaterial Engineering Center, one of six centres of Semiconductor Technology Advanced Research network, a Semiconductor Research Corporation programme sponsored by Microelectronics Advanced Research Corporation and DARPA. P.U. and J.G.A. acknowledge partial support from a Qualcomm Innovation Fellowship.

Author information

Author notes

    • Guoqiang Yu
    •  & Pramey Upadhyaya

    These authors contributed equally to this work

Affiliations

  1. Department of Electrical Engineering, University of California, Los Angeles, California 90095, USA

    • Guoqiang Yu
    • , Pramey Upadhyaya
    • , Yabin Fan
    • , Juan G. Alzate
    • , Wanjun Jiang
    • , Kin L. Wong
    • , Li-Te Chang
    • , Murong Lang
    • , Jianshi Tang
    • , Pedram Khalili Amiri
    •  & Kang L. Wang
  2. Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA

    • So Takei
    • , Scott A. Bender
    •  & Yaroslav Tserkovnyak
  3. Center for Electron Microscopy and State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China

    • Ying Jiang
    •  & Yong Wang

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Contributions

G.Q.Y. and P.U. jointly conceived the idea with contributions from Y.T., P.K.A. and K.L.W. G.Q.Y. designed the experiments to test the idea, fabricated and measured the devices, with contributions from Y.F., J.G.A., W.J., K.W., L.T.C., M.L., J.T., Y.J. and Y.W. P.U. performed the theoretical analysis and modelling, with help from S.T., S.A.B. and Y.T. G.Q.Y., P.U., P.K.A. and K.L.W. wrote the paper. All authors discussed the results and commented on the manuscript. The study was performed under the supervision of P.K.A. and K.L.W.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Guoqiang Yu or Kang L. Wang.

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DOI

https://doi.org/10.1038/nnano.2014.94

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