Regensburg 2022 – scientific programme
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MA: Fachverband Magnetismus
MA 21: Terahertz Spintronics
MA 21.7: Talk
Wednesday, September 7, 2022, 11:00–11:15, H43
Spin-orbit torque mediated coupling of terahertz light with magnon modes in heavy-metal/ferromagnet heterostructures — •Ruslan Salikhov1, Igor Ilyakov1, Lukas Körber1, Attila Kákay1, Kilian Lenz1, Jürgen Fassbender1, Stefano Bonetti2,3, Olav Hellwig1,4, Jürgen Lindner1, and Sergey Kovalev1 — 1Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany — 2Stockholm University, Stockholm, Sweden — 3University of Venice, Venice, Italy — 4Chemnitz University of Technology, Chemnitz, Germany
Nonvolatile and energy-efficient spin-based technologies call for new prospects to realize computation and communication devices that are able to operate at terahertz (THz) frequencies. In particular, the coupling of electro-magnetic radiation to a spin system is a general requirement for future communication units and sensors. Here we propose a layered metallic system, based on a ferromagnetic film sandwiched in between two heavy metals that allows a highly effective coupling of millimeter wavelength THz light to nanometer-wavelength magnon modes. Using single-cycle broadband THz radiation we are able to excite spin-wave modes with a frequency of up to 0.6 THz and a wavelength as short as 6 nm. Our experimental and theoretical studies demonstrate that the coupling originates solely from interfacial spin-orbit torques. These results are of general applicability to magnetic multilayered structures, and offer the perspective of coherent THz excitation of exchange-dominated nanoscopic magnon modes.