Letter

Fast domain wall motion in the vicinity of the angular momentum compensation temperature of ferrimagnets

Received:
Accepted:
Published online:

Abstract

Antiferromagnetic spintronics is an emerging research field which aims to utilize antiferromagnets as core elements in spintronic devices1,2. A central motivation towards this direction is that antiferromagnetic spin dynamics is expected to be much faster than its ferromagnetic counterpart3. Recent theories indeed predicted faster dynamics of antiferromagnetic domain walls (DWs) than ferromagnetic DWs4,5,6. However, experimental investigations of antiferromagnetic spin dynamics have remained unexplored, mainly because of the magnetic field immunity of antiferromagnets7. Here we show that fast field-driven antiferromagnetic spin dynamics is realized in ferrimagnets at the angular momentum compensation point TA. Using rare earth–3d-transition metal ferrimagnetic compounds where net magnetic moment is nonzero at TA, the field-driven DW mobility is remarkably enhanced up to 20 km s−1 T−1. The collective coordinate approach generalized for ferrimagnets8 and atomistic spin model simulations6,9 show that this remarkable enhancement is a consequence of antiferromagnetic spin dynamics at TA. Our finding allows us to investigate the physics of antiferromagnetic spin dynamics and highlights the importance of tuning of the angular momentum compensation point of ferrimagnets, which could be a key towards ferrimagnetic spintronics.

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Acknowledgements

This work was partly supported by JSPS KAKENHI Grant Numbers 15H05702, 26870300, 26870304, 26103002, 25220604, 2604316 Collaborative Research Program of the Institute for Chemical Research, Kyoto University, the Cooperative Research Project Program of the Research Institute of Electrical Communication, Tohoku University, and R&D project for ICT Key Technology of MEXT from the Japan Society for the Promotion of Science (JSPS). K.-J.K. was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea Government (MSIP) (No. 2017R1C1B2009686, NRF-2016R1A5A1008184) and by the DGIST R&D Program of the Ministry of Science, ICT and Future Planning (17-BT-02). S.K.K. and Y.T. acknowledge support from the Army Research Office under Contract No. W911NF-14-1-0016. D.-H.K. was supported by an Overseas Researcher under Postdoctoral Fellowship of JSPS (Grant Number P16314). K.-J.L. acknowledges support from the National Research Foundation of Korea (NRF-2015M3D1A1070465, NRF-2017R1A2B2006119).

Author information

Author notes

    • Kab-Jin Kim
    •  & Se Kwon Kim

    These authors contributed equally to this work.

Affiliations

  1. Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan

    • Kab-Jin Kim
    • , Yuushou Hirata
    • , Takayuki Tono
    • , Duck-Ho Kim
    • , Takaya Okuno
    • , Woo Seung Ham
    • , Sanghoon Kim
    • , Takahiro Moriyama
    •  & Teruo Ono
  2. Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea

    • Kab-Jin Kim
  3. Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA

    • Se Kwon Kim
    •  & Yaroslav Tserkovnyak
  4. Department of Nano-Semiconductor and Engineering, Korea University, Seoul 02841, Korea

    • Se-Hyeok Oh
    •  & Kyung-Jin Lee
  5. Department of Materials Science & Engineering, Korea University, Seoul 02841, South Korea

    • Gyoungchoon Go
    •  & Kyung-Jin Lee
  6. College of Science and Technology, Nihon University, Funabashi, Chiba 274-8501, Japan

    • Arata Tsukamoto
  7. KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, South Korea

    • Kyung-Jin Lee
  8. Center for Spintronics Research Network (CSRN), Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan

    • Teruo Ono

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Contributions

K.-J.K., T.M. and T.O. planned the study. A.T. grew and optimized the GdFeCo film. Y.H. and T.T. fabricated the device and performed the experiment with the guidance of K.-J.K. D.-H.K., T.Okuno, W.-S.H. and S.K. helped with the experiment. S.K.K., K.-J.L. and Y.T. provided theory. S.-H.O., G.G. and K.-J.L. performed the numerical simulation. K.-J.K., S.K.K., K.-J.L., T.M. and T.O. analysed the results. K.-J.K., S.K.K., K.-J.L., T.M. and T.O. wrote the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Kab-Jin Kim or Kyung-Jin Lee or Teruo Ono.

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