Efficient generation, propagation, control, and detection of spin waves is essential for development of magnonic components for conventional and neuromorphic computing. Spin wave wavelengths can be as short as nanometers, while their frequencies reach Terahertz, and working with such waves is a challenging task in magnonics. Promising approach to this issue is to exploit femtomagnetic phenomena – ultrafast laser-induced changes of magnetic parameters in combination with strong localization of laser pulses.
In this talk, we first discuss generation of magnetostatic waves – spin waves near the centre of the Brillouin zone in anisotropic ferromagnetic films based on a laser-driven localized perturbation of magnetic anisotropy [1-3]. Based on experimental findings and micromagnetic simulations, we suggest a tunable source of magnetostatic wavepackets using a focused laser pulse and a spin texture in a magnonic waveguide [4].
Next, we demonstrate a novel regime of spin waves generation facilitated by magneto-elastic interaction. This regime can be understood as a magnon-Cherenkov effect with the laser-induced picosecond strain pulse serving as a localized moving source of the spin wave [5], and enables reaching spin waves beyond the magnetostatic regime [6].
Finally, we tackle a problem of reaching ultimate exchange waves – those at the edge of the Brillouin zone, that cannot be realized so far via the above mentioned approaches. We show how ultrafast perturbation of the exchange interaction drives coupled spin-wave pairs across the whole Brillouin zone – two-magnon modes, and outline an approach to selective excitation of two-magnon modes with different wavevectors [7-9].
The work was supported by RSF grant No. 23-12-00251.
[1] A. M. Kalashnikova et al., Tech. Phys. 67, 2335 (2022).
[2] N. E. Khokhlov et al., Phys. Rev. Appl. 12, 044044 (2019).
[3] Ia. A. Filatov et al., Appl. Phys. Lett. 120, 112404 (2022).
[4] P. I. Gerevenkov et al., Phys. Rev. Appl. 19, 024062 (2023).
[5] P. I. Gerevenkov et al., arXiv:2505.09579.
[6] Ia. A. Filatov et al, submitted.
[7] A. E. Fedianin et al., Phys, Rev. B 107, 144430 (2023).
[8] F. Formisano et al., APL Mater. 12, 011105 (2024).
[9] A. E. Fedianin et al. Phys. Rev. B 110, 174439 (2024).