Adiabatic Control of Spin-Wave Propagation using Magnetisation Gradients

TL;DR

This paper introduces a method to control spin-wave propagation in magnetic films using laser-induced magnetisation gradients, enabling efficient two-dimensional information transport by locally modifying dispersion relations.

Contribution

It presents a novel approach employing reconfigurable magnetisation gradients to manipulate spin-wave modes and directions, overcoming previous anisotropic dispersion limitations.

Findings

Achieved controlled spin-wave refraction and adiabatic modification.

Demonstrated broad frequency range control with high efficiency.

Enabled two-dimensional spin-wave information transport.

Abstract

Spin waves are of large interest as data carriers for future logic devices. However, due to the strong anisotropic dispersion relation of dipolar spin-waves in in-plane magnetised films the realisation of two-dimensional information transport remains a challenge. Bending of the energy flow is prohibited since energy and momentum of spin waves cannot be conserved while changing the direction of wave propagation. Thus, non-linear or non-stationary mechanisms are usually employed. Here, we propose to use reconfigurable laser-induced magnetisation gradients to break the system's translational symmetry. The resulting changes in the magnetisation shift the dispersion relations locally and allow for operating with different spin-wave modes at the same frequency. Spin-wave momentum is first transformed via refraction at the edge of the magnetisation gradient region and then adiabatically modified inside it. Along these lines the spin-wave propagation direction can be controlled in a broad frequency range with high efficiency.