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MA: Fachverband Magnetismus

MA 41: Poster III

MA 41.14: Poster

Donnerstag, 20. März 2025, 15:00–17:30, P3

Terahertz field induced spin wave excitation in thin ferromagnetic metals — •Sergei Ovcharenko, Hoppe Wolfgang, Alexey Melnikov, and Georg Woltersdorf — Institute of Physics, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 3, Halle 06120, Germany

In the novel concepts of charge-less data processing technologies spin waves are proposed as a carriers of data. One of the ways to excite and study the properties of spin waves on the picosecond time scale is to use the laser pulsed excitation and magneto optical probe. Optical excitation of spin waves in ferromagnetic metals has now been demonstrated using a short pulse of spin current leading to spin torque localized at the interfaces of a ferromagnetic and nonmagnetic metal, both with optical [1] and Terahertz (THz) excitation [2]. The use of short optical pulses in the THz spectral range to induce spin currents and generate spin-orbit torque (SOT) offers undeniable advantages: the SOT is linearly proportional to the THz field amplitude, the excitation and spin-wave frequencies can be well-matched, and minimal heating occurs due to the low excitation energy.

In our work, we demonstrate the optical excitation of spin waves in thin layers of ferromagnetic metals using the THz pump-optical probe technique, with a spintronic emitter as the source of THz radiation. We investigate the dependence of the excited modes on the thickness of the ferromagnetic metal. [1] Brandt Liane et al. Physical Review B 104.9 (2021): 094415. [2] Salikhov Ruslan et al. Nature Physics 19.4 (2023): 529-535.

Keywords: Spin-orbit torque; Spin waves; Pump-probe; Terahertz (THz) excitation