Analytical dispersion relation for forward volume spin waves in ferrimagnets near the angular momentum compensation condition

TL;DR

This paper derives analytical dispersion relations for forward volume spin waves in ferrimagnets near the angular momentum compensation point and validates them with micromagnetic simulations, aiding magnonic device design.

Contribution

It provides the first analytical expressions for spin wave dispersion in ferrimagnets near the compensation point, bridging theory and simulation.

Findings

Two branches of spin waves merge at the compensation point

Analytical results agree with micromagnetic simulations

Predictions can guide ferrimagnetic magnonic device development

Abstract

Antiferromagnetic magnonics has become the focus of intense scientific research because of the advantages of these materials compared to ferromagnets. However, ferrimagnetic materials have received much less attention despite exhibiting similar dynamical features at the angular momentum compensation point. In this paper, we present analytical expressions describing the dispersion relation of forward volume spin waves in ferrimagnetic materials near the angular momentum compensation point. Besides, we benchmark the derived dispersion relations with full micromagnetic simulations showing a complete agreement between both approaches. This work predicts two different branches for forward volume spin waves in ferrimagnetic materials merging into a single branch at the angular momentum compensation point. Our results can assist in the design of magnonic devices built on ferrimagnetic materials.