Impact of Spin Wave Dispersion on Surface Acoustic Wave Velocity

TL;DR

This paper investigates how spin wave dispersion influences surface acoustic wave velocity in a magnetic thin film, revealing strong dependence on magnetic field parameters and validating a phenomenological model against experimental data.

Contribution

It introduces a phenomenological approach that accurately models SAW velocity changes by incorporating spin wave dispersion effects, validated against a quasi-exact magnetoelastic model.

Findings

SAW velocity depends on magnetic field amplitude and direction

Phenomenological model reproduces experimental velocity variations

Model validated against magnetoelastic calculations

Abstract

The dependence of the velocity of surface acoustic wave (SAW) as a function of an external applied magnetic field is investigated in a Fe thin film epitaxially grown on a piezoelectric GaAs substrate. The SAW velocity is observed to strongly depend on both the amplitude and direction of the magnetic field. To interpret the experimental data a phenomenological approach to the relative change in SAW velocity is implemented. We find that the experimental velocity variation can be well reproduced provided that the spin wave dispersion is taken into account. The validity of this phenomenological model is attested by the comparison with a quasi-exact magnetoelastic one.