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.
Subscribe to Journal
Get full journal access for 1 year
only $15.58 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
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.
The script for modelling spin wave propagation was written in MATLAB (Mathworks). The codes are available from the corresponding author upon reasonable request.
Jungwirth, T., Marti, X., Wadley, P. & Wunderlich, J. Antiferromagnetic spintronics. Nat. Nanotechnol. 11, 231–241 (2016).
Baltz, V. et al. Antiferromagnetic spintronics. Rev. Mod. Phys. 90, 015005 (2018).
Wang, H., Du, C., Hammel, P. C. & Yang, F. Antiferromagnonic spin transport from Y3Fe5O12 into NiO. Phys. Rev. Lett. 113, 097202 (2014).
Hahn, C. et al. Conduction of spin currents through insulating antiferromagnetic oxides. Europhys. Lett. 108, 57005 (2014).
Seki, S. et al. Thermal generation of spin current in an antiferromagnet. Phys. Rev. Lett. 115, 266601 (2015).
Wu, S. M. et al. Antiferromagnetic spin seebeck effect. Phys. Rev. Lett. 116, 097204 (2016).
Qiu, Z. et al. Spin colossal magnetoresistance in an antiferromagnetic insulator. Nat. Mater. 17, 577–580 (2018).
Yuan, W. et al. Experimental signatures of spin superfluid ground state in canted antiferromagnet Cr2O3 via nonlocal spin transport. Sci. Adv. 4, eaat1098 (2018).
Lebrun, R. et al. Tunable long-distance spin transport in a crystalline antiferromagnetic iron oxide. Nature 561, 222–225 (2018).
Gomonay, O., Baltz, V., Brataas, A. & Tserkovnyak, Y. Antiferromagnetic spin textures and dynamics. Nat. Phys. 14, 213–216 (2018).
Keffer, F. & Kittle, C. Theory of antiferromagnetic resonance. Phys. Rev. 85, 329–337 (1952).
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).
Williamson, S. J. & Foner, S. Antiferromagnetic resonance in systems with Dzyaloshinsky-Moriya coupling; orientation dependence in α-Fe2O3. Phys. Rev. 136, A1102–A1106 (1964).
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).
Rezende, S. M., Rodríguez-Suárez, R. L. & Azevedo, A. Diffusive magnonic spin transport in antiferromagnetic insulators. Phys. Rev. B 93, 054412 (2016).
Chen, X. Z. et al. Antidamping-torque-induced switching in biaxial antiferromagnetic insulators. Phys. Rev. Lett. 120, 207204 (2018).
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).
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).
Sulymenko, O. R. et al. Terahertz-frequency spin Hall auto-oscillator based on a canted antiferromagnet. Phys. Rev. Appl. 8, 064007 (2017).
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).
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).
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).
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).
Cheng, R., Xiao, J., Niu, Q. & Brataas, A. Spin pumping and spin-transfer torques in antiferromagnets. Phys. Rev. Lett. 113, 057601 (2014).
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).
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).
Zhou, X. J. et al. Lateral transport properties of thermally excited magnons in yttrium iron garnet films. Appl. Phys. Lett. 110, 062407 (2017).
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).
Searle, C. W. & Dean, G. W. Temperature and field dependence of the weak ferromagnetic moment of hematite. Phys. Rev. B 1, 4337–4342 (1970).
Kamra, A., Agrawal, U. & Belzig, W. Noninteger-spin magnonic excitations in untextured magnets. Phys. Rev. B 96, 020411(R) (2017).
Alikhanov, R. A. et al. Investigation of magnon dispersion relation in α-Fe2O3 – additional data. Phys. Stat. Sol. 41, K103–K106 (1970).
Cheng, R., Daniels, M. W., Zhu, J.-G. & Xiao, D. Antiferromagnetic spin wave field effect transistor. Sci. Rep. 6, 24223 (2016).
Bender, S. A. & Tserkovnyak, Y. Interfacial spin and heat transfer between metals and magnetic insulators. Phys. Rev. B 91, 140402(R) (2015).
Bayrakci, S. P., Keller, T., Habicht, K. & Keimer, B. Spin-wave lifetimes throughout the Brillouin zone. Science 312, 1926–1929 (2006).
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).
Ross, A. et al. Propagation length of magnons governed by domain configurations. Nano Lett. 20, 306–313 (2019).
Olejník, K. et al. Terahertz electrical writing speed in an antiferromagnetic memory. Sci. Adv. 4, eaar3566 (2018).
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).
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.
The authors declare no competing interests.
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.
About this article
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