We demonstrate that single pulse all optical helicity independent switching can be generalized for a large range of rare earth–transition metal multilayers. The threshold fluence for switching is observed to be independent of the pulse duration and, at high laser intensities, concentric ring domain structures are induced, unveiling multiple fluence thresholds. These striking switching features point towards an intrinsic precessional reversal mechanism.
Single-pulse switching under zero applied field. a Background subtracted images after each single pulse with 1.9mJ/cm² laser pulse at 50 fs. b Background subtracted images after first single with 50 fs laser pulse of different fluences.
Single Pulse All Optical Switching represents the ability to reverse the magnetization of a nanostructure using a femtosecond single laser pulse without any applied field. Since the first switching experiments carried out on GdFeCo ferrimagnets, this phenomena has been only recently extended to a few other materials, MnRuGa alloys and Tb/Co multilayers with a very specific range of thickness and composition.
Here, we demonstrate that single pulse switching can be obtained for a large range of rare earth–transition metal multilayers, making this phenomenon much more general. Surprisingly, the threshold fluence for switching is observed to be independent of the laser pulse duration. Moreover, at high laser intensities, concentric ring domain structures are induced. These striking features contrast to those observed in Gd based materials pointing towards a different reversal mechanism. Concomitant with the demonstration of an in-plane magnetization reorientation, a precessional reversal mechanism explains all the observed features.
This is a first detailed materials paper study, allowing to develop and understand ultrafast single shot magnetization switching in Gd free materials. This work can be an important milestone of the research in the field of all-optical switching toward applications (including future developments on theory, experiments and applications), which will further expand the pivotal role that spintronics can play for the future of ultrafast and ultralow power microelectronics, so important for the digital world.
Collaboration: Institut Jean-Lamour, Nancy
Funding: ANR (ANR-17-CE24-0007 UFO project); European Union’s Horizon 2020 research and innovation programme under Marie Skłodowska-Curie grant agreement No 861300 (COMRAD).
Further reading: In-plane reorientation induced single laser pulse magnetization reversal, Y Peng, D Salomoni, G Malinowski, W Zhang, J Hohlfeld, LD Buda-Prejbeanu, J Gorchon, M Vergès, JX Lin, D Lacour, RC Sousa, IL Prejbeanu, S Mangin, M Hehn, Nat Commun 14, 5000 (2023).
Field-Free All-Optical Switching and Electrical Readout of Tb/Co-Based Magnetic Tunnel Junctions,, D. Salomoni, Y. Peng, L. Farcis, S. Auffret, M. Hehn, G. Malinowski, S. Mangin, B. Dieny, L.D. Buda-Prejbeanu, R.C. Sousa, and I.L. Prejbeanu Phys. Rev. Applied 20, 034070 (2023).
https://doi.org/10.1038/s41467-023-40721-z/ Open access: hal-04229028