Simulations of magnetization reversal in FM/AFM bilayers with THz frequency pulses

HIRST, Joel, RUTA, Sergiu, JACKSON, Jerome and OSTLER, Thomas (2023). Simulations of magnetization reversal in FM/AFM bilayers with THz frequency pulses. Scientific Reports, 13 (1): 12270.

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Abstract

It is widely known that antiferromagnets (AFMs) display a high frequency response in the terahertz (THz) range, which opens up the possibility for ultrafast control of their magnetization for next generation data storage and processing applications. However, because the magnetization of the different sublattices cancel, their state is notoriously difficult to read. One way to overcome this is to couple AFMs to ferromagnets—whose state is trivially read via magneto-resistance sensors. Here we present conditions, using theoretical modelling, that it is possible to switch the magnetization of an AFM/FM bilayer using THz frequency pulses with moderate field amplitude and short durations, achievable in experiments. Consistent switching is observed in the phase diagrams for an order of magnitude increase in the interface coupling and a tripling in the thickness of the FM layer. We demonstrate a range of reversal paths that arise due to the combination of precession in the materials and the THz-induced fields. Our analysis demonstrates that the AFM drives the switching and results in a much higher frequency dynamics in the FM due to the exchange coupling at the interface. The switching is shown to be robust over a broad range of temperatures relevant for device applications.

Item Type:	Article
Additional Information:	** From Springer Nature via Jisc Publications Router ** Licence for this article: http://creativecommons.org/licenses/by/4.0/ ** Acknowledgements: This work was supported by the EPSRC TERASWITCH project (Project ID EP/T027916/1). Simulations were completed using resources provided by the Cambridge Tier-2 system operated by the University of Cambridge Research Computing Service (www.hpc.cam.ac.uk) funded by EPSRC Tier-2 capital grant EP/T022159/1 as well as the Baskerville Tier 2 HPC service. Baskerville was funded by the EPSRC and UKRI through the World Class Labs scheme (EP/T022221/1) and the Digital Research Infrastructure programme (EP/W032244/1) and is operated by Advanced Research Computing at the University of Birmingham. **Journal IDs: eissn 2045-2322 **Article IDs: publisher-id: s41598-023-39175-6; manuscript: 39175 **History: collection 12-2023; online 28-07-2023; published_online 28-07-2023; registration 21-07-2023; accepted 20-07-2023; submitted 10-05-2023
Identification Number:	https://doi.org/10.1038/s41598-023-39175-6
SWORD Depositor:	Colin Knott
Depositing User:	Colin Knott
Date Deposited:	31 Jul 2023 10:27
Last Modified:	11 Oct 2023 13:00
URI:	https://shura.shu.ac.uk/id/eprint/32203

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