Identification of spin wave modes strongly coupled to a co-axial cavity

TL;DR

This study demonstrates strong room-temperature coupling between specific magnetostatic modes of a YIG sphere and a co-axial cavity's electromagnetic modes, enabling mode identification through measured coupling strengths.

Contribution

It introduces a method to identify magnetostatic modes via their coupling strengths with a co-axial cavity at room temperature.

Findings

Strong coupling observed at room temperature.

Coupling strengths enable mode identification.

Specific modes have distinct coupling profiles.

Abstract

We demonstrate, at room temperature, the strong coupling of the fundamental and non-uniform magnetostatic modes of an yttrium iron garnet (YIG) ferrimagnetic sphere to the electromagnetic modes of a co-axial cavity. The well-defined field profile within the cavity yields a specific coupling strength for each magnetostatic mode. We experimentally measure the coupling strength for the different magnetostatic modes and, by calculating the expected coupling strengths, are able to identify the modes themselves.