Room Temperature Evolution of Laser‐Induced Ultrafast Spin and Phonon Dynamics in T van der Waals Magnets FexGeTe2 (x = 3, 4, 5)

Abstract 2D van der Waals (vdW) magnets are the incentive for a new era of spintronics research with unprecedented opportunities. Hitherto, maximum research on vdW magnets is restricted by cryogenic temperature due to the inability to retain long‐range magnetic order at room temperature. The present study demonstrates the emergence of spin dynamics in association with phonon dynamics at room temperature in chemically exfoliated Fe x GeTe 2 ( x = 3,4,5) flakes employing a time‐resolved magneto‐optical Kerr effect microscope. The highly intense femtosecond laser pulse is supposed to establish magnetic ordering. This photoinduced magnetization is realized and modulated in the ultrafast demagnetization and GHz frequency precessional dynamics. Furthermore, coherent phonon excitation at optical regime is observed which subsequently triggers THz frequency magnon modes via direct spin‐phonon coupling. This study unfolds an all‐optical route to control optomagnetic properties and the future perspectives of 2D vdW magnets for multidisciplinary applications.