Refractive index and Snell's Law for Dipolar-Exchange Spin-Waves in a Confined Planar Structure

TL;DR

This paper derives analytical expressions for the refractive index and Snell's law for dipolar-exchange spin waves at magnetic interfaces, revealing novel total reflection phenomena in confined planar structures.

Contribution

It introduces a microscopic scattering approach to derive optical properties of spin waves at magnetic interfaces, including the prediction of total reflection in specific material combinations.

Findings

Analytical forms of refractive index and Snell's law for spin waves.

Demonstration of optical total reflection at YIG/Permalloy interface.

Validation through micromagnetic numerical calculations.

Abstract

We derived the analytical forms of refractive index and Snell law for dipolar-exchange spin waves of reflection and refraction at a magnetically heterogeneous interface in a geometrically confined planer structure composed of different magnetic thin films from a microscopic scattering approach. A novel behavior, the optical total reflection, was demonstrated for spin waves with a specific interface between Yttrium iron garnet (Y3Fe5O12) and Permalloy (Ni80Fe20), by analytical and micromagnetic numerical calculations.