Bulk Dzyaloshinskii–Moriya interaction in amorphous ferrimagnetic alloys

Abstract

Symmetry breaking is a fundamental concept that prevails in many branches of physics1,2,3,4,5. In magnetic materials, broken inversion symmetry induces the Dzyaloshinskii–Moriya interaction (DMI), which results in fascinating physical behaviours6,7,8,9,10,11,12,13,14 with the potential for application in future spintronic devices15,16,17. Here, we report the observation of a bulk DMI in GdFeCo amorphous ferrimagnets. The DMI is found to increase linearly with an increasing thickness of the ferrimagnetic layer, which is a clear signature of the bulk nature of DMI. We also found that the DMI is independent of the interface between the heavy metal and ferrimagnetic layer. This bulk DMI is attributed to an asymmetric distribution of the elemental content in the GdFeCo layer, with spatial inversion symmetry broken throughout the layer. We expect that our experimental identification of a bulk DMI will open up additional possibilities to exploit this interaction in a wide range of materials.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

Fig. 1: Schematic illustration of amorphous ferrimagnets and the experimental set-up for DMI measurements.
Fig. 2: Thickness dependence of DMI in SiN/GdFeCo/SiN samples.
Fig. 3: Characteristics of GdFeCo films through STEM and EELS.
Fig. 4: Tight-binding model calculation of the DMI energy for TM/RE bilayers with a composition gradient.
Fig. 5: Thickness dependence of DMI in SiN/GdFeCo/SiN, SiN/GdFeCo/Pt and SiN/GdFeCo/Cu samples.

References

  1. 1.

    Anderson, P. W. More is different. Science 177, 393–396 (1972).

    CAS  Article  Google Scholar 

  2. 2.

    Siegel, J. S. Biochemistry: single-handed cooperation. Nature 409, 777–778 (2001).

    CAS  Article  Google Scholar 

  3. 3.

    Ellis, J. Particle physics: antimatter matters. Nature 424, 631–634 (2003).

    CAS  Article  Google Scholar 

  4. 4.

    Bode, M. et al. Chiral magnetic order at surfaces driven by inversion asymmetry. Nature 447, 190–193 (2007).

    CAS  Article  Google Scholar 

  5. 5.

    Yu, X. Z. et al. Real-space observation of a two-dimensional skyrmion crystal. Nature 465, 901–904 (2010).

    CAS  Article  Google Scholar 

  6. 6.

    Je, S.-G. et al. Asymmetric magnetic domain-wall motion by the Dzyaloshinskii–Moriya interaction. Phys. Rev. B 88, 214401 (2013).

    Article  Google Scholar 

  7. 7.

    Cho, J. et al. Thickness dependence of the interfacial Dzyaloshinskii–Moriya interaction in inversion symmetry broken systems. Nat. Commun. 6, 7635 (2015).

    Article  Google Scholar 

  8. 8.

    Nembach, H. T., Shaw, J. M., Weiler, M., Jué, E. & Silva, T. J. Linear relation between Heisenberg exchange and interfacial Dzyaloshinskii–Moriya interaction in metal films. Nat. Phys. 11, 825–829 (2015).

    CAS  Article  Google Scholar 

  9. 9.

    Pizzini, S. et al. Chirality-induced asymmetric magnetic nucleation in Pt/Co/AlOx ultrathin microstructures. Phys. Rev. Lett. 113, 047203 (2014).

    CAS  Article  Google Scholar 

  10. 10.

    Yoshimura, Y. et al. Soliton-like magnetic domain wall motion induced by the interfacial Dzyaloshinskii–Moriya interaction. Nat. Phys. 12, 157–161 (2016).

    CAS  Article  Google Scholar 

  11. 11.

    Kim, D.-H., Kim, D.-Y., Yoo, S.-C., Min, B.-C. & Choe, S.-B. Universality of Dzyaloshinskii–Moriya interaction effect over domain-wall creep and flow regimes. Phys. Rev. B 99, 134401 (2019).

    CAS  Article  Google Scholar 

  12. 12.

    Ryu, K.-S., Thomas, L., Yang, S.-H. & Parkin, S. Chiral spin torque at magnetic domain walls. Nat. Nanotechnol. 8, 527–533 (2013).

    CAS  Article  Google Scholar 

  13. 13.

    Haazen, P. P. J. et al. Domain wall depinning governed by the spin Hall effect. Nat. Mater. 12, 299–303 (2013).

    CAS  Article  Google Scholar 

  14. 14.

    Emori, S., Bauer, U., Ahn, S.-M., Martinez, E. & Beach, G. S. D. Current-driven dynamics of chiral ferromagnetic domain walls. Nat. Mater. 12, 611–616 (2013).

    CAS  Article  Google Scholar 

  15. 15.

    Parkin, S. S. P., Hayashi, M. & Thomas, L. Magnetic domain-wall racetrack memory. Science 320, 190–194 (2008).

    CAS  Article  Google Scholar 

  16. 16.

    Boulle., O. et al. Room-temperature chiral magnetic skyrmions in ultrathin magnetic nanostructures. Nat. Nanotechnol. 11, 449–454 (2016).

    CAS  Article  Google Scholar 

  17. 17.

    Moon, K.-W. et al. Magnetic bubblecade memory based on chiral domain walls. Sci. Rep. 5, 9166 (2015).

    Article  Google Scholar 

  18. 18.

    Dzialoshinskii, I. E. Thermodynamic theory of ‘weak’ ferromagnetism in antiferromagnetic substances. Sov. Phys. JETP 5, 1259–1272 (1957).

    Google Scholar 

  19. 19.

    Moriya, T. Anisotropic superexchange interaction and weak ferromagnetism. Phys. Rev. 120, 91–98 (1960).

    CAS  Article  Google Scholar 

  20. 20.

    Thiaville, A., Rohart, S., Jué, É., Cros, V. & Fert, A. Dynamics of Dzyaloshinskii domain walls in ultrathin magnetic films. Europhys. Lett. 100, 57002 (2012).

    Article  Google Scholar 

  21. 21.

    Rößler, U. K., Bogdanov, A. N. & Pfleiderer, C. Spontaneous skyrmion ground states in magnetic metals. Nature 442, 797–801 (2006).

    Article  Google Scholar 

  22. 22.

    Uchida, M., Onose, Y., Matsui, Y. & Tokura, Y. Real-space observation of helical spin order. Science 311, 359–361 (2006).

    CAS  Article  Google Scholar 

  23. 23.

    Mühlbauer, S. et al. Skyrmion lattice in a chiral magnet. Science 323, 915–919 (2009).

    Article  Google Scholar 

  24. 24.

    Radu, I. et al. Transient ferromagnetic-like state mediating ultrafast reversal of antiferromagnetically coupled spins. Nature 472, 205–208 (2011).

    CAS  Article  Google Scholar 

  25. 25.

    Kim, K.-J. et al. Fast domain wall motion in the vicinity of the angular momentum compensation temperature of ferrimagnets. Nat. Mater. 16, 1187–1192 (2017).

    CAS  Article  Google Scholar 

  26. 26.

    Mangin, S. et al. Engineered materials for all-optical helicity-dependent magnetic switching. Nat. Mater. 13, 286–292 (2014).

    CAS  Article  Google Scholar 

  27. 27.

    Tono, T. et al. Chiral magnetic domain wall in ferrimagnetic GdFeCo wires. Appl. Phys. Express 8, 073001 (2015).

    Article  Google Scholar 

  28. 28.

    Ostler, T. A. et al. Crystallographically amorphous ferrimagnetic alloys: comparing a localized atomistic spin model with experiments. Phys. Rev. B 84, 024407 (2011).

    Article  Google Scholar 

  29. 29.

    Kim, S. et al. Magnetic droplet nucleation with a homochiral Néel domain wall. Phys. Rev. B 95, 220402(R) (2017).

    Article  Google Scholar 

  30. 30.

    Harris, V. G., Aylesworth, K. D., Das, B. N., Elam, W. T. & Koon, N. C. Structural origins of magnetic anisotropy in sputtered amorphous Tb–Fe films. Phys. Rev. Lett. 69, 1939 (1992).

    CAS  Article  Google Scholar 

  31. 31.

    Hufnagel, T. C., Brennan, S., Zschack, P. & Clemens, B. M. Structural anisotropy in amorphous Fe–Tb thin films. Phys. Rev. B 53, 12024 (1996).

    CAS  Article  Google Scholar 

  32. 32.

    Haltz, E. et al. Deviations from bulk behavior in TbFe(Co) thin films: interfaces contribution in the biased composition. Phys. Rev. Mater. 2, 104410 (2018).

    CAS  Article  Google Scholar 

  33. 33.

    Kashid, V. et al. Dzyaloshinskii–Moriya interaction and chiral magnetism in 3d–5d zigzag chains: tight-binding model and ab initio calculations. Phys. Rev. B 90, 054412 (2014).

    Article  Google Scholar 

Download references

Acknowledgements

This work was supported by the Japan Society for the Promotion of Science (JSPS) KAKENHI (grant nos 15H05702, 26870300, 26870304, 26103002, 26103004, 25220604 and 2604316), the Collaborative Research Program of the Institute for Chemical Research, Kyoto University, and the R & D project for ICT Key Technology of MEXT from the JSPS. This work was partly supported by The Cooperative Research Project Program of the Research Institute of Electrical Communication, Tohoku University. D.-H.K. was supported as an Overseas Researcher under a Postdoctoral Fellowship of JSPS (grant no. P16314). K.-J.L. was supported by the National Research Foundation of Korea (NRF-2017R1A2B2006119), the Samsung Research Funding Center of Samsung Electronics under project no. SRFCMA1702-02 and the Korea Institute of Science and Technology (KIST) Institutional Program (project no. 2V05750). D.-Y.K. and S.-B.C. were supported by the Samsung Science & Technology Foundation (SSTF-BA1802-07) and the National Research Foundations of Korea (NRF) funded by the Ministry of Science and ICT (MSIT) (2015M3D1A1070465). D.-Y.K. was supported by the KIST institutional program (grant no. 2E29410) and the National Research Council of Science & Technology (grant no. CAP-16-01-KIST) funded by the Korea government (MSIT). S.K. was supported by the Creative Materials Discovery Program (2018M3D1A1089406) and the Basic Research Laboratory Program (NRF-2018R1A4A1020696) through the NRF.

Author information

Affiliations

Authors

Contributions

D.-H.K. conceptualized the work. D.-H.K. and T. Ono supervised the study. Y.F., H.Y. and A.T. prepared the films and T.N., T. Okuno, Y.H. and W.H. fabricated the devices. D.-H.K. and T.N. conducted the experiments for the DMI measurement. D.-Y.K. and S.-B.C. helped with the experiment for the asymmetric domain expansion. M.H. and H.K. performed the microscopy experiments. H.-W.K., G.G., H.-J.P. and K.-J.L. performed the numerical calculation based on the tight-binding model. D.-H.K. performed the analysis. D.-H.K., K.-J.L. and T.-Ono wrote the manuscript. All the authors discussed the results and commented on the manuscript.

Corresponding authors

Correspondence to Duck-Ho Kim or Teruo Ono.

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 Notes 1–7, Supplementary Figs. 1–9, Supplementary Tables 1 and 2, and Supplementary References 1–13.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Kim, DH., Haruta, M., Ko, HW. et al. Bulk Dzyaloshinskii–Moriya interaction in amorphous ferrimagnetic alloys. Nat. Mater. 18, 685–690 (2019). https://doi.org/10.1038/s41563-019-0380-x

Download citation

Further reading

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