Contact solitons as spin pistons in one-dimensional ferromagnetic channels

TL;DR

This paper explores how contact solitons in ferromagnetic channels can act as spin pistons, enabling controlled magnon injection and modulation of dissipative exchange flows through varying injection currents.

Contribution

It introduces the concept of modulating contact soliton DEFs as a novel mechanism for magnon injection and control in ferromagnetic channels.

Findings

Injected magnons follow the DEF dispersion relation.

Varying injection current modulates the DEF parameters.

Contact solitons can pump magnons along ferromagnetic channels.

Abstract

Ferromagnetic channels subject to spin injection have been theoretically shown to sustain dissipative exchange flows (DEFs). In the strong injection regime, a soliton is stabilized at the injection site, which has been termed a contact soliton DEF or CS-DEF. Here, we investigate the modulation of CS-DEFs as a mechanism to inject magnons into a DEF. By varying the injection current, the parameters connecting the soliton with the DEF via a boundary layer are varied. These lead to a modification in the DEF which is interpreted as a spin piston. The injected magnons follow the expected dispersion relation of DEFs, akin to the Bogoliubov - de Gennes dispersion relation. This work demonstrates that changes in the injected current can pumping magnons along a ferromagnetic channel via dissipative exchange flows.