Ultra-fast all optical switching in spintronic devices. – ( Stéphane Mangin / LPCNO / Seminar). – 19/12/2024, 14H.

Séminaire LPCNO

Stéphane Mangin Institut Jean Lamour, Nancy

GP seminar room, INSA, Build. 27, Room 2.20 (2nd floor left)

Abstract
We will focus exclusively on deterministic magnetization switching induced by single femtosecond or picosecond laser pulses in spintronic devices, such as spin valves and tunnel junctions. We will examine magnetization reversal resulting from the direct interaction between the ultra-short laser pulse and the magnetization,. We’ll also discuss how light can produce heat pulses or spin-polarized femtosecond current pulses to reverse the magnetization of thin ferromagnetic films in magnetic heterostructures, a topic also recently reviewed. Additionally, we will present our latest results, which demonstrate ultra-fast magnetization reversal (in less than one picosecond) in various perpendicularly magnetized ferrimagnetic and ferromagnetic spin-valve structures [1,2].

More recently, we have demonstrated optically induced ultrafast magnetization reversal occurring in less than a picosecond in rare-earth-free archetypal spin valves ([Pt/Co]/Cu/[Co/Pt]) commonly utilized for current-induced spin-transfer torque (STT) switching [2]. We discovered that the magnetization of the free layer can be switched from parallel to antiparallel alignment, akin to STT switching, revealing the presence of an unexpected, intense, and ultrafast source of opposite angular momentum in our structures. These findings pave the way for ultrafast magnetization control by integrating concepts from spintronics and ultrafast magnetism.

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[20] J. Igarashi, et al Nano Lett. 20, 8654 (2020).
[21] Q. Remy, et al Adv. Sci. 7, 2001996 (2020).
[22] Q. Remy, Phys. Rev. B 107, 174431 (2023)
[23] J. Igarashi et al, Nature Mat, 114 36(2023)
[24] J-X. Lin et al Phys. Rev. Appl. 22 (4), 044051 (2024)