Tunable magnon-magnon coupling in synthetic antiferromagnets

TL;DR

This paper investigates tunable magnon-magnon coupling in synthetic antiferromagnets using microwave spectroscopy, revealing controllable hybridization of spin-wave modes influenced by tilt angle, exchange field, and damping effects.

Contribution

It introduces a phenomenological model for magnon-magnon coupling in SyAFs and demonstrates how coupling strength can be tuned by structural and magnetic parameters.

Findings

Coupling strength is controlled by out-of-plane tilt angle.

Hybridization of spin-wave modes observed at degeneracy points.

Spin-current mediated damping influences the coupling.

Abstract

In this work, we study magnon-magnon coupling in synthetic antiferromagnets (SyAFs) using microwave spectroscopy at room temperature. Two distinct spin-wave modes are clearly observed and are hybridised at degeneracy points. We provide a phenomenological model that captures the coupling phenomena and experimentally demonstrate that the coupling strength is controlled by the out-of-plane tilt angle as well as the interlayer exchange field. We numerically show that a spin-current mediated damping in SyAFs plays a role in influencing the coupling strength.