Optimal protocol for spin-orbit torque switching of a perpendicular nanomagnet

• Published in: Physical Review B
• Main Authors: Vlasov, Sergei M., Kwiatkowski, Grzegorz J., Lobanov, Igor S., Uzdin, Valery M., Bessarab, Pavel
• Other Authors: Raunvísindastofnun (HÍ), Science Institute (UI), Verkfræði- og náttúruvísindasvið (HÍ), School of Engineering and Natural Sciences (UI), Háskóli Íslands, University of Iceland
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Physical Society (APS) 2022
• Subjects: Stærðfræðileg eðlisfræði; spin dynamics; spintronics; magnetization switching; magnetic nanoparticles; Landau-Lifshitz-Gilbert equation; Mathematical physics methods; Iceland
• Online Access: https://hdl.handle.net/20.500.11815/3064; https://doi.org/10.1103/PhysRevB.105.134404

©2022 American Physical Society It is demonstrated by means of the optimal control theory that the energy cost of the spin-orbit torque induced reversal of a nanomagnet with perpendicular anisotropy can be strongly reduced by proper shaping of both in-plane components of the current pulse. The time dependence of the optimal switching pulse that minimizes the energy cost associated with joule heating is derived analytically in terms of the required reversal time and material properties. The optimal reversal time providing a tradeoff between the switching speed and energy efficiency is obtained. A sweet-spot balance between the fieldlike and dampinglike components of the spin-orbit torque is discovered; it permits for a particularly efficient switching by a down-chirped rotating current pulse whose duration does not need to be adjusted precisely. Funded by the Russian Science Foundation (Grant No.19-72-10138), the Icelandic Research Fund (Grant No. 184949), the University of Iceland Research Fund (Grant No. 15673), and the Swedish Research Council (Grant No. 2020-05110). Peer Reviewed