Birefringence-like spin transport via linearly polarized antiferromagnetic magnons

Abstract

Antiferromagnets (AFMs) possess great potential in spintronics because of their immunity to external magnetic disturbance, the absence of a stray field or the resonance in the terahertz range1,2. The coupling of insulating AFMs to spin–orbit materials3,4,5,6,7 enables spin transport via AFM magnons. In particular, spin transmission over several micrometres occurs in some AFMs with easy-axis anisotropy8,9. Easy-plane AFMs with two orthogonal, linearly polarized magnon eigenmodes own unique advantages for low-energy control of ultrafast magnetic dynamics2. However, it is commonly conceived that these magnon modes are less likely to transmit spins because of their vanishing angular momentum9,10,11. Here we report experimental evidence that an easy-plane insulating AFM, an α-Fe2O3 thin film, can efficiently transmit spins over micrometre distances. The spin decay length shows an unconventional temperature dependence that cannot be captured considering solely thermal magnon scatterings. We interpret our observations in terms of an interference of two linearly polarized, propagating magnons in analogy to the birefringence effect in optics. Furthermore, our devices can realize a bi-stable spin-current switch with a 100% on/off ratio under zero remnant magnetic field. These findings provide additional tools for non-volatile, low-field control of spin transport in AFM systems.

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: Antiferromagnetic magnon modes and materials properties.
Fig. 2: Non-local measurements at room temperature.
Fig. 3: Spin transport as a function of temperature and magnon frequency.
Fig. 4: Non-volatile modulation of spin transport.

Data availability

The data that support the findings of this study are presented in the main text and the Supplementary Information, and are available from the corresponding author upon reasonable request.

Code availability

The script for modelling spin wave propagation was written in MATLAB (Mathworks). The codes are available from the corresponding author upon reasonable request.

References

  1. 1.

    Jungwirth, T., Marti, X., Wadley, P. & Wunderlich, J. Antiferromagnetic spintronics. Nat. Nanotechnol. 11, 231–241 (2016).

    CAS  Article  Google Scholar 

  2. 2.

    Baltz, V. et al. Antiferromagnetic spintronics. Rev. Mod. Phys. 90, 015005 (2018).

    CAS  Article  Google Scholar 

  3. 3.

    Wang, H., Du, C., Hammel, P. C. & Yang, F. Antiferromagnonic spin transport from Y3Fe5O12 into NiO. Phys. Rev. Lett. 113, 097202 (2014).

    Article  Google Scholar 

  4. 4.

    Hahn, C. et al. Conduction of spin currents through insulating antiferromagnetic oxides. Europhys. Lett. 108, 57005 (2014).

    Article  Google Scholar 

  5. 5.

    Seki, S. et al. Thermal generation of spin current in an antiferromagnet. Phys. Rev. Lett. 115, 266601 (2015).

    CAS  Article  Google Scholar 

  6. 6.

    Wu, S. M. et al. Antiferromagnetic spin seebeck effect. Phys. Rev. Lett. 116, 097204 (2016).

    Article  Google Scholar 

  7. 7.

    Qiu, Z. et al. Spin colossal magnetoresistance in an antiferromagnetic insulator. Nat. Mater. 17, 577–580 (2018).

    CAS  Article  Google Scholar 

  8. 8.

    Yuan, W. et al. Experimental signatures of spin superfluid ground state in canted antiferromagnet Cr2O3 via nonlocal spin transport. Sci. Adv. 4, eaat1098 (2018).

    Article  Google Scholar 

  9. 9.

    Lebrun, R. et al. Tunable long-distance spin transport in a crystalline antiferromagnetic iron oxide. Nature 561, 222–225 (2018).

    CAS  Article  Google Scholar 

  10. 10.

    Gomonay, O., Baltz, V., Brataas, A. & Tserkovnyak, Y. Antiferromagnetic spin textures and dynamics. Nat. Phys. 14, 213–216 (2018).

    CAS  Article  Google Scholar 

  11. 11.

    Keffer, F. & Kittle, C. Theory of antiferromagnetic resonance. Phys. Rev. 85, 329–337 (1952).

    CAS  Article  Google Scholar 

  12. 12.

    Cornelissen, L. J., Liu, J., Duine, R. A., Youssef, J. B. & van Wees, B. J. Long-distance transport of magnon spin information in a magnetic insulator at room temperature. Nat. Phys. 11, 1022–1026 (2015).

    CAS  Article  Google Scholar 

  13. 13.

    Williamson, S. J. & Foner, S. Antiferromagnetic resonance in systems with Dzyaloshinsky-Moriya coupling; orientation dependence in α-Fe2O3. Phys. Rev. 136, A1102–A1106 (1964).

    Article  Google Scholar 

  14. 14.

    Khymyn, R., Lisenkov, I., Tiberkevich, V. S., Slavin, A. N. & Ivanov, B. A. Transmission of spin current by antiferromagnetic insulators. Phys. Rev. B 93, 224421 (2016).

    Article  Google Scholar 

  15. 15.

    Rezende, S. M., Rodríguez-Suárez, R. L. & Azevedo, A. Diffusive magnonic spin transport in antiferromagnetic insulators. Phys. Rev. B 93, 054412 (2016).

    Article  Google Scholar 

  16. 16.

    Chen, X. Z. et al. Antidamping-torque-induced switching in biaxial antiferromagnetic insulators. Phys. Rev. Lett. 120, 207204 (2018).

    CAS  Article  Google Scholar 

  17. 17.

    Baldrati, L. et al. Mechanism of Néel order switching in antiferromagnetic thin films revealed by magnetotransport and direct imaging. Phys. Rev. Lett. 123, 177201 (2019).

    CAS  Article  Google Scholar 

  18. 18.

    Cheng, Y., Yu, S., Zhu, M., Hwang, J. & Yang, F. Electrical switching of tristate antiferromagnetic Néel order in α-Fe2O3 epitaxial films. Phys. Rev. Lett. 124, 027202 (2020).

    CAS  Article  Google Scholar 

  19. 19.

    Sulymenko, O. R. et al. Terahertz-frequency spin Hall auto-oscillator based on a canted antiferromagnet. Phys. Rev. Appl. 8, 064007 (2017).

    Article  Google Scholar 

  20. 20.

    Shimomura, N. et al. Morin transition temperature in (0001)-oriented α-Fe2O3 thin film and effect of Ir doping. J. Appl. Phys. 117, 17C736 (2015).

    Article  Google Scholar 

  21. 21.

    Fujii, T., Takano, M., Kakano, R., Isozumi, Y. & Bando, Y. Spin-flip anomalies in epitaxial α-Fe2O3 films by Mössbauer spectroscopy. J. Magn. Magn. Mater. 135, 231–236 (1994).

    CAS  Article  Google Scholar 

  22. 22.

    Gota, S., Gautier-Soyer, M. & Sacchi, M. Magnetic properties of Fe2O3(0001) thin layers studied by soft X-ray linear dichroism. Phys. Rev. B 64, 224407 (2001).

    Article  Google Scholar 

  23. 23.

    Wesenberg, D., Liu, T., Balzar, D., Wu, D. & Zink, B. L. Long-distance spin transport in a disordered magnetic insulator. Nat. Phys. 13, 987–993 (2017).

    CAS  Article  Google Scholar 

  24. 24.

    Cheng, R., Xiao, J., Niu, Q. & Brataas, A. Spin pumping and spin-transfer torques in antiferromagnets. Phys. Rev. Lett. 113, 057601 (2014).

    Article  Google Scholar 

  25. 25.

    Giles, B. L., Yang, Z., Jamison, J. S. & Myers, R. C. Long-range pure magnon spin diffusion observed in a nonlocal spin-Seebeck geometry. Phys. Rev. B 92, 224415 (2015).

    Article  Google Scholar 

  26. 26.

    Guo, E.-J. et al. Influence of thickness and interface on the low-temperature enhancement of the spin Seebeck effect in YIG films. Phys. Rev. X 6, 031012 (2016).

    Google Scholar 

  27. 27.

    Zhou, X. J. et al. Lateral transport properties of thermally excited magnons in yttrium iron garnet films. Appl. Phys. Lett. 110, 062407 (2017).

    Article  Google Scholar 

  28. 28.

    Cornelissen, L. J., Shan, J. & van Wees, B. J. Temperature dependence of the magnon spin diffusion length and magnon spin conductivity in the magnetic insulator yttrium iron garnet. Phys. Rev. B 94, 180402(R) (2016).

    Article  Google Scholar 

  29. 29.

    Searle, C. W. & Dean, G. W. Temperature and field dependence of the weak ferromagnetic moment of hematite. Phys. Rev. B 1, 4337–4342 (1970).

    Article  Google Scholar 

  30. 30.

    Kamra, A., Agrawal, U. & Belzig, W. Noninteger-spin magnonic excitations in untextured magnets. Phys. Rev. B 96, 020411(R) (2017).

    Article  Google Scholar 

  31. 31.

    Alikhanov, R. A. et al. Investigation of magnon dispersion relation in α-Fe2O3 – additional data. Phys. Stat. Sol. 41, K103–K106 (1970).

    CAS  Article  Google Scholar 

  32. 32.

    Cheng, R., Daniels, M. W., Zhu, J.-G. & Xiao, D. Antiferromagnetic spin wave field effect transistor. Sci. Rep. 6, 24223 (2016).

    CAS  Article  Google Scholar 

  33. 33.

    Bender, S. A. & Tserkovnyak, Y. Interfacial spin and heat transfer between metals and magnetic insulators. Phys. Rev. B 91, 140402(R) (2015).

    Article  Google Scholar 

  34. 34.

    Bayrakci, S. P., Keller, T., Habicht, K. & Keimer, B. Spin-wave lifetimes throughout the Brillouin zone. Science 312, 1926–1929 (2006).

    CAS  Article  Google Scholar 

  35. 35.

    Chmiel, F. P. et al. Observation of magnetic vortex pairs at room temperature in a planar α-Fe2O3/Co heterostructure. Nat. Mater. 17, 581–585 (2018).

    CAS  Article  Google Scholar 

  36. 36.

    Ross, A. et al. Propagation length of magnons governed by domain configurations. Nano Lett. 20, 306–313 (2019).

    Article  Google Scholar 

  37. 37.

    Olejník, K. et al. Terahertz electrical writing speed in an antiferromagnetic memory. Sci. Adv. 4, eaar3566 (2018).

    Article  Google Scholar 

  38. 38.

    Chiang, C. C., Huang, S. Y., Qu, D., Wu, P. H. & Chien, C. L. Absence of evidence of electrical switching of the antiferromagnetic Néel vector. Phys. Rev. Lett. 123, 227203 (2019).

    CAS  Article  Google Scholar 

Download references

Acknowledgements

This work is supported in part by National Science Foundation under award no. ECCS-1808826, AFOSR, and by SMART, one of seven centres of nCORE, a Semiconductor Research Corporation programme, sponsored by National Institutes of Standards and Technology (NIST). The material synthesis and characterization are partially supported by the National Science Foundation under award no. DMR 14-19807 through the MRSEC shared facilities. J.H. thanks Y. Lin, P.-C. Shih and A.-Y. Lu for help with measurements.

Author information

Affiliations

Authors

Contributions

J.H. fabricated the devices and performed the electrical measurements with technical support from Y.F., T.S.S. and J.X. P.Z. prepared the α-Fe2O3 thin-film samples. P.Z. and J.F. characterized the samples. R.C., L.L, Z.B., L.F. and J.H. performed theoretical analysis. All authors commented on the manuscript.

Corresponding author

Correspondence to Luqiao Liu.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Peer review information Nature Nanotechnology thanks Jun’ichi Ieda and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary texts and Figs. 1–13.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Han, J., Zhang, P., Bi, Z. et al. Birefringence-like spin transport via linearly polarized antiferromagnetic magnons. Nat. Nanotechnol. 15, 563–568 (2020). https://doi.org/10.1038/s41565-020-0703-8

Download citation