Observation of nonreciprocal diffraction of surface acoustic wave

TL;DR

This paper reports the first observation of nonreciprocal diffraction of surface acoustic waves using a magnetoelastic grating, revealing asymmetric diffraction intensities linked to ferromagnetic resonance, with potential applications in advanced SAW devices.

Contribution

It demonstrates nonreciprocal diffraction of surface acoustic waves, extending the phenomenon beyond photons and providing a theoretical explanation based on ferromagnetic resonance.

Findings

Asymmetric diffraction intensities observed in SAW with ferromagnetic resonance.

Resonant scattering involving ferromagnetic excitations explains the phenomenon.

Potential applications in microwave communications and quantum engineering.

Abstract

Rectification phenomenon caused by the simultaneous breaking of time reversal and spatial inversion symmetries has been extended to a wide range of (quasi)particles and waves; however, the nonreciprocal diffraction, which is the imbalance of upward and downward deflections, was previously observed only for photons and remained to be extended to other (quasi)particles. In this study, we present evidence of the nonreciprocal diffraction of surface acoustic wave (SAW) utilizing a magnetoelastic grating on a SAW device. Asymmetric diffraction intensities were observed when the ferromagnetic resonance was acoustically excited. Based on a theoretical model, we attribute the microscopic origin of this phenomenon to the resonant scattering involving ferromagnetic resonance excitations. The novel property may pave an avenue to further development of SAW devices for various purposes, including microwave communications and quantum engineering applications.