Goos-Hanchen shift of a spin-wave beam transmitted through anisotropic interface between two ferromagnets

TL;DR

This paper investigates the Goos-Hanchen shift of spin-wave beams transmitted through an anisotropic interface between ferromagnets, providing analytical formulas and micromagnetic simulations to understand the influence of interface properties on wave transmission.

Contribution

It introduces the first analytical formulas for the refracted spin-wave beam's properties, including the Goos-Hanchen shift, considering anisotropic interfaces in ferromagnetic materials.

Findings

Analytical formulas for reflectance, transmittance, phase shift, and GH shift.

Confirmation of GH shifts via micromagnetic simulations.

Dependence of wave properties on interface anisotropy, incidence angle, and frequency.

Abstract

The main object of investigation in magnonics, spin waves (SWs) are promising information carriers. Presently the most commonly studied are plane wave-like SWs and SWs propagating in confined structures, such as waveguides. Here we consider a Gaussian SW beam obliquely incident on an ultra-narrow interface between two identical ferromagnetic materials. We use an analytical model and micromagnetic simulations for an in-depth analysis of the influence of the interface properties, in particular the magnetic anisotropy, on the transmission of the SW beam. We derive analytical formulas for the reflectance, transmittance, phase shift and Goos-Hanchen (GH) shift for beams reflected and refracted by an interface between two semi-infinite ferromagnetic media; the results for the refracted beam are the first to be reported to date. The GH shifts in SW beam reflection and transmission are confirmed by micromagnetic simulations in the thin-film geometry. We demonstrate the dependence of the characteristic properties on the magnetic anisotropy at the interface, the angle of incidence and the frequency of the SWs. We also propose a method for the excitation of high-quality SW beams in micromagnetic simulations.