Spin–orbit torque can be used to manipulate magnetization in spintronic devices. However, conventional ferromagnetic spin–orbit torque systems have intrinsic limitations in terms of operation speed due to their inherent magnetization dynamics. Antiferromagnets and ferrimagnets with antiparallel exchange coupling exhibit faster spin dynamics and could potentially overcome these limitations. Here, we report ultrafast spin–orbit torque-induced magnetization switching in ferrimagnetic cobalt-gadolinium (CoGd) alloy devices. Using a stroboscopic pump–probe technique to perform time-resolved measurements, we show that the switching time in the ferrimagnets can be reduced to the subnanosecond regime and a domain wall velocity of 5.7 km s‒1 can be achieved, which is in agreement with analytical modelling and atomistic spin simulations. We also find that the switching energy efficiency in the ferrimagnets is one to two orders of magnitude higher than that of ferromagnets.
Subscribe to Journal
Get full journal access for 1 year
only $8.67 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 plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.
Wolf, S. A. et al. Spintronics: a spin-based electronics vision for the future. Science 294, 1488–1495 (2001).
Žutić, I., Fabian, J. & Das Sarma, S. Spintronics: fundamentals and applications. Rev. Mod. Phys. 76, 323–410 (2004).
Miron, I. M. et al. Perpendicular switching of a single ferromagnetic layer induced by in-plane current injection. Nature 476, 189–193 (2011).
Liu, L. et al. Spin–torque switching with the giant spin Hall effect of tantalum. Science 336, 555–558 (2012).
Manchon, A. et al. Current-induced spin–orbit torques in ferromagnetic and antiferromagnetic systems. Rev. Mod. Phys. 91, 035004 (2019).
Ramaswamy, R., Lee, J. M., Cai, K. & Yang, H. Recent advances in spin–orbit torques: moving towards device applications. Appl. Phys. Rev. 5, 031107 (2018).
Yang, S. H., Ryu, K. S. & Parkin, S. Domain-wall velocities of up to 750 m s−1 driven by exchange-coupling torque in synthetic antiferromagnets. Nat. Nanotechnol. 10, 221–226 (2015).
Fukami, S., Zhang, C., DuttaGupta, S., Kurenkov, A. & Ohno, H. Magnetization switching by spin–orbit torque in an antiferromagnet–ferromagnet bilayer system. Nat. Mater. 15, 535–541 (2016).
Sato, N., Xue, F., White, R. M., Bi, C. & Wang, S. X. Two-terminal spin–orbit torque magnetoresistive random access memory. Nat. Electron. 1, 508–511 (2018).
Garello, K. et al. Ultrafast magnetization switching by spin–orbit torques. Appl. Phys. Lett. 105, 212402 (2014).
Cubukcu, M. et al. Ultra-fast perpendicular spin–orbit torque MRAM. IEEE Trans. Magn. 54, 9300204 (2018).
Gomonay, O., Jungwirth, T. & Sinova, J. High antiferromagnetic domain wall velocity induced by Néel spin–orbit torques. Phys. Rev. Lett. 117, 017202 (2016).
Baltz, V. et al. Antiferromagnetic spintronics. Rev. Mod. Phys. 90, 015005 (2018).
Olejník, K. et al. Terahertz electrical writing speed in an antiferromagnetic memory. Sci. Adv. 4, eaar3566 (2018).
Wadley, P. et al. Electrical switching of an antiferromagnet. Science 351, 587–590 (2016).
Mishra, R. et al. Anomalous current-induced spin torques in ferrimagnets near compensation. Phys. Rev. Lett. 118, 167201 (2017).
Yu, J. et al. Long spin coherence length and bulk-like spin–orbit torque in ferrimagnetic multilayers. Nat. Mater. 18, 29–34 (2019).
Finley, J. & Liu, L. Spin–orbit torque efficiency in compensated ferrimagnetic cobalt–terbium alloys. Phys. Rev. Appl. 6, 054001 (2016).
Chen, J.-Y., He, L., Wang, J.-P. & Li, M. All-optical switching of magnetic tunnel junctions with single subpicosecond laser pulses. Phys. Rev. Appl. 7, 021001 (2017).
Jeong, J. et al. Termination layer compensated tunnelling magnetoresistance in ferrimagnetic Heusler compounds with high perpendicular magnetic anisotropy. Nat. Commun. 7, 10276 (2016).
Kaiser, C., Panchula, A. F. & Parkin, S. S. Finite tunnelling spin polarization at the compensation point of rare-earth-metal-transition-metal alloys. Phys. Rev. Lett. 95, 047202 (2005).
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).
Caretta, L. et al. Fast current-driven domain walls and small skyrmions in a compensated ferrimagnet. Nat. Nanotechnol. 13, 1154–1160 (2018).
Bläsing, R. et al. Exchange coupling torque in ferrimagnetic Co/Gd bilayer maximized near angular momentum compensation temperature. Nat. Commun. 9, 4984 (2018).
Siddiqui, S. A., Han, J., Finley, J. T., Ross, C. A. & Liu, L. Current-induced domain wall motion in a compensated ferrimagnet. Phys. Rev. Lett. 121, 057701 (2018).
Lee, J. M. et al. Oscillatory spin–orbit torque switching induced by field-like torques. Commun. Phys. 1, 2 (2018).
Yoon, J. et al. Anomalous spin–orbit torque switching due to field-like torque-assisted domain wall reflection. Sci. Adv. 3, e1603099 (2017).
Zhu, Z., Fong, X. & Liang, G. Theoretical proposal for determining angular momentum compensation in ferrimagnets. Phys. Rev. B 97, 184410 (2018).
Roschewsky, N., Lambert, C.-H. & Salahuddin, S. Spin–orbit torque switching of ultralarge-thickness ferrimagnetic GdFeCo. Phys. Rev. B 96, 064406 (2017).
Binder, M. et al. Magnetization dynamics of the ferrimagnet CoGd near the compensation of magnetization and angular momentum. Phys. Rev. B 74, 134404 (2006).
Decker, M. M. et al. Time resolved measurements of the switching trajectory of Pt/Co elements induced by spin–orbit torques. Phys. Rev. Lett. 118, 257201 (2017).
Baumgartner, M. et al. Spatially and time-resolved magnetization dynamics driven by spin–orbit torques. Nat. Nanotechnol. 12, 980–986 (2017).
Beach, G. S. D., Nistor, C., Knutson, C., Tsoi, M. & Erskine, J. L. Dynamics of field-driven domain-wall propagation in ferromagnetic nanowires. Nat. Mater. 4, 741–744 (2005).
Torrejon, J., Martinez, E. & Hayashi, M. Tunable inertia of chiral magnetic domain walls. Nat. Commun. 7, 13533 (2016).
Graves, C. E. et al. Nanoscale spin reversal by non-local angular momentum transfer following ultrafast laser excitation in ferrimagnetic GdFeCo. Nat. Mater. 12, 293–298 (2013).
Bergeard, N. et al. Ultrafast angular momentum transfer in multisublattice ferrimagnets. Nat. Commun. 5, 3466 (2014).
Radu, I. et al. Transient ferromagnetic-like state mediating ultrafast reversal of antiferromagnetically coupled spins. Nature 472, 205–208 (2011).
Thielemann-Kühn, N. et al. Ultrafast and energy-efficient quenching of spin order: antiferromagnetism beats ferromagnetism. Phys. Rev. Lett. 119, 197202 (2017).
Ostler, T. A. et al. Crystallographically amorphous ferrimagnetic alloys: comparing a localized atomistic spin model with experiments. Phys. Rev. B 84, 024407 (2011).
This work was supported by the SpOT-LITE programme (A*STAR grant no. A18A6b0057) through RIE2020 funds and the National Research Foundation (NRF), Prime Minister’s Office, Singapore, under its Competitive Research Programme (CRP award no. NRFCRP12-2013-01). We thank K.J. Lee for discussions.
The authors declare no competing interests.
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
About this article
Cite this article
Cai, K., Zhu, Z., Lee, J.M. et al. Ultrafast and energy-efficient spin–orbit torque switching in compensated ferrimagnets. Nat Electron 3, 37–42 (2020). https://doi.org/10.1038/s41928-019-0345-8