Gespeichert in:
| Hauptverfasser: | , , , , , , |
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| Format: | Preprint |
| Veröffentlicht: |
2025
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| Schlagworte: | |
| Online-Zugang: | https://arxiv.org/abs/2505.09579 |
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Inhaltsangabe:
- The development of magnonics requires energy-efficient methods for generating spin waves and controlling their parameters. Acoustic waves are known to resonantly excite spin waves through magneto-elastic wave formation or to induce non-resonant forced magnetization oscillations. Short acoustic wavepackets enable another unexplored resonant interaction regime -- the Cherenkov radiation of spin waves. This raises a question regarding the criteria and signatures of these three regimes of picosecond magnetoacoustics.Here, we use a scanning magneto-optical pump-probe technique to directly observe all three regimes of interaction between laser-driven acoustic and magnetostatic wavepackets in a thin permalloy film and a waveguide fabricated on Si substrate. Direct measurements of the phase velocities reveal the transition from a coupled magneto-elastic wavepacket to Cherenkov-like radiation and the non-resonant regime, controlled by the detuning between magnon and phonon group velocities. The acoustic pulse is found to be affected by the excited magnetization dynamics only in the magneto-elastic regime.