Spin wave non-reciprocity and beating in permalloy by time-resolved magneto-optical Kerr effect

TL;DR

This paper investigates spin wave propagation in permalloy stripes using time-resolved magneto-optical Kerr effect, revealing non-reciprocal behavior, beating interference patterns, and localized edge mode differences.

Contribution

It demonstrates the non-reciprocal propagation and interference patterns of spin waves in permalloy stripes with spatial and magnetic field dependence analysis.

Findings

Observation of beating interference patterns in spin waves.

Identification of non-reciprocal propagation behavior.

Localized edge modes have lower frequency than center modes.

Abstract

We have studied the propagation characteristics of spin wave modes in a permalloy stripe by time-resolved magneto-optical Kerr effect techniques. We observe a beating interference pattern in the time domain under the influence of an electrical square pulse excitation at the center of the stripe. We also probe the non-reciprocal behavior of propagating spin waves with a dependence on the external magnetic field. Spatial dependence studies show that localized edge mode spin waves have a lower frequency than spin waves in the center of the stripe, due to the varying magnetization vector across the width of the stripe.