Imaging Nonlinear Spin Waves in Magnetoacoustic Devices

TL;DR

This study uses NV centers in diamond to spatially map and analyze nonlinear spin wave processes in magnetoacoustic devices, revealing heterogeneous noise generation and threshold behaviors that impact sensor performance.

Contribution

It introduces a novel application of NV centers for high-resolution mapping of nonlinear magnon dynamics in magnetoacoustic systems.

Findings

Heterogeneous magnetic noise observed at micron scales.

NV center relaxation rates increase with drive power.

Identification of noise sources limiting sensor performance.

Abstract

Magnetoacoustic systems offer promising platforms for next-generation sensors and computing applications, but understanding their nonlinear dynamics remains challenging. Here, we use nitrogen vacancy (NV) centers in diamond to spatially map nonlinear magnon scattering processes in FeGaB/LiNbO3 magnetoacoustic devices with sub-micron resolution. We observe highly heterogeneous magnetic noise generation under acoustic driving at 1425 MHz, with responses varying dramatically across micron length scales. Time-domain measurements reveal threshold-like nonlinear behavior where NV center spin relaxation rates increase over two orders of magnitude as drive power is increased. These findings reveal microscopic noise sources that limit magnetoacoustic sensor performance while simultaneously demonstrating how acoustic mode engineering could enable selective control of nonlinear magnon processes.