2025/05/14 by P. I. Gerevenkov, Ia. A. Mogunov, Gerevenkov, P. I. +11 · 1 citation
Engineering · Materials Science · #FOS: Physical sciences #Magnetic Properties and Applications #Materials Science (cond-mat.mtrl-sci) #Non-Destructive Testing Techniques
paper · pdf · doi:10.48550/arxiv.2505.09579
openalex publication_date 2025/05/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
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 and transitions between them in confined magnetic structures. 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.