Seminar – Ultrafast magnetization reversal in ferromagnetic spin valve

On Wednesday, January 11th 2023, we have the pleasure to welcome in SPINTEC Junta Igarashi from Institut Jean Lamour, Université de Lorraine. He will give us seminar at 16:00, entitled :

Ultrafast magnetization reversal in ferromagnetic spin valves

Place : CEA Building 10.05 auditorium 445 (access needs authorization *)
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Abstract : The manipulation of magnetic materials without the use of magnetic fields is of great fundamental and technical interest. The discovery of spin-transfer torque (STT) [1,2] allowed us to control the magnetization direction electrically in magnetic devices within nanoseconds, which paved the way for non-volatile applications such as spin-transfer-torque magnetoresistive random access memory (STT-MRAM). However, current-induced STT switching below a few hundred picoseconds with low power consumption while maintaining high thermal stability is challenging. Ultra-short optical pulses can induce spin angular momentum transfer in a ferromagnetic spin valve, resulting in different demagnetization time depending on its magnetic configuration within less than a picosecond [3]. However, magnetization reversal in ferromagnetic spin valves by a single femtosecond laser pulse has not been achieved. In this seminar, I will show our recent work, where we demonstrated sub- picosecond magnetization reversal of a Co/Pt ferromagnetic layer induced by a single femtosecond laser pulse within a common [Co/Pt]/Cu/[Co/Pt] perpendicular spin-valve structure [4, 5].

References :
[1] J. C. Slonczewski, Journal of Magnetism and Magnetic Materials 159, L1‒L7 (1996).
[2] L. Berger, Phys. Rev. B 54, 9353‒9358 (1996).
[3] G. Malinowski et al ., Nature Phys., 4, 855-858 (2008).
[4] S. Mangin et al., Nature Mater 5, 210‒215 (2006)
[5] J. Igarashi et al., under review.

Short bio : Junta Igarashi received the Ph.D. degree from Tohoku University, Sendai, Japan, in 2021. He then became postdoctoral fellow at Research Institute of Electrical Communication, Tohoku University (2021). At Tohoku University, he worked on research and development of ultra- small magnetic tunnel junctions (MTJs). He is currently postdoctoral fellow at Institut Jean Lamour, Université de Lorraine, funded by a Japan society for the promotion of science (JSPS) overseas research fellowship. His current research topic is to explore magnetization reversal in ultrafast timescales.

(*) Persons who do not have a CEA badge must request an entry authorization sufficiently in advance, before January 05th at

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