Ultrafast Magnetoelastic Probing of Surface Acoustic Transients

TL;DR

This paper demonstrates ultrafast generation and control of magnetoelastic waves in nickel films using optical techniques, revealing resonant coupling with surface acoustic waves and enabling selective excitation.

Contribution

It introduces a novel optical method to generate and tune magnetoelastic waves, with analytical support confirming the surface acoustic transients involved.

Findings

Resonant excitation of Rayleigh and Longitudinal surface acoustic waves.

Selective tuning of magnetoelastic coupling via in-plane magnetic field.

Analytical Green's function model corroborates experimental results.

Abstract

We generate in-plane magnetoelastic waves in nickel films using the all-optical transient grating technique. When performed on amorphous glass substrates, two dominant magnetoelastic excitations can be resonantly driven by the underlying elastic distortions, the Rayleigh Surface Acoustic Wave and the Surface Skimming Longitudinal Wave. An applied field, oriented in the sample plane, selectively tunes the coupling between magnetic precession and one of the elastic waves, thus demonstrating selective excitation of coexisting, large amplitude magnetoelastic waves. Analytical calculations based on the Green's function approach corroborate the generation of the non-equilibrium surface acoustic transients.