Unidirectional spin wave emission by travelling pair of magnetic field profiles

TL;DR

This paper introduces a method to generate unidirectional, tunable spin wave emission using traveling magnetic field profiles, leveraging the spin wave Cherenkov effect for potential applications in magnonic devices.

Contribution

It proposes a novel approach using a pair of moving magnetic field profiles to control spin wave direction and frequency, with potential for experimental realization in hybrid systems.

Findings

Unidirectional spin wave emission achieved with traveling magnetic profiles.

Control over emission direction and frequency via velocity tuning.

Potential for confinement of spin waves between moving profiles.

Abstract

We demonstrate that the spin wave Cherenkov effect can be used to design the unidirectional spin wave emitter with tunable frequency and switchable direction of emission. In our numerical studies, we propose to use a pair of traveling profiles of the magnetic field which generate the spin waves, for sufficiently large velocity of their motion. In the considered system, the spin waves of shorter (longer) wavelengths are induced at the front (back) of the moving profiles and interfere constructively or destructively, depending on the velocity of the profiles. Moreover, we showed that the spin waves can be confined between the pair of traveling profiles of the magnetic field. This work opens the perspectives for the experimental studies in hybrid magnonic-superconducting systems where the magnetic vortices in a superconductor can be used as moving sources of the magnetic field driving the spin waves in the ferromagnetic subsystem.