Chiral Pumping of Spin Waves

TL;DR

This paper presents a theoretical study of chiral pumping of spin waves in magnetic films via dipolar coupling, revealing a unidirectional magnon flow driven by temperature gradients, with implications for spintronic devices.

Contribution

It introduces a theory for chiral spin wave pumping and the chiral spin Seebeck effect in magnetic films, highlighting unidirectional magnon flow due to dipolar interactions and temperature gradients.

Findings

Unidirectional spin wave injection broadens ferromagnetic resonance.

Temperature gradients induce a chiral spin Seebeck effect.

The theory explains coherent and incoherent magnon flows in magnetic films.

Abstract

We report a theory for the coherent and incoherent chiral pumping of spin waves into thin magnetic films through the dipolar coupling with a local magnetic transducer, such as a nanowire. The ferromagnetic resonance of the nanowire is broadened by the injection of unidirectional spin waves that generate a non-equilibrium magnetization in only half of the film. A temperature gradient between the local magnet and film leads to a unidirectional flow of incoherent magnons, i.e., a chiral spin Seebeck effect.