Traveling surface spin-wave resonance spectroscopy using surface acoustic waves

TL;DR

This paper demonstrates a novel surface acoustic wave-based method for precise, quantitative spin-wave spectroscopy in ferromagnetic thin films, capable of measuring dispersion and damping over a wide range of wave vectors.

Contribution

It introduces a new technique using traveling surface acoustic waves to perform detailed spin-wave spectroscopy on ferromagnetic films.

Findings

Successfully measured spin-wave properties of Ni thin film across a broad wave vector range.

Showed the technique can determine both isotropic and anisotropic contributions to dispersion and damping.

Validated the method's effectiveness for analyzing dipolar interactions in ferromagnetic materials.

Abstract

Coherent gigahertz-frequency surface acoustic waves (SAWs) traveling on the surface of a piezoelectric crystal can, via the magnetoelastic interaction, resonantly excite traveling spin waves in an adjacent thin-film ferromagnet. These excited spin waves, traveling with a definite in-plane wave-vector q enforced by the SAW, can be detected by measuring changes in the electro-acoustical transmission of a SAW delay line. Here, we provide a first demonstration that such measurements constitute a precise and quantitative technique for spin-wave spectroscopy, providing a means to determine both isotropic and anisotropic contributions to the spin-wave dispersion and damping. We demonstrate the effectiveness of this spectroscopic technique by measuring the spin-wave properties of a Ni thin film for a large range of wave vectors,q = 2.5 x 10^4 - 8 x 10^4 cm^(-1), over which anisotropic dipolar interactions vary from being negligible to quite significant.