Magnetic Domain Wall Floating on a Spin Superfluid

TL;DR

This paper explores how a spin superfluid can transfer angular momentum to move a magnetic domain wall, enabling potential applications in low-dissipation spintronic devices.

Contribution

It introduces a theoretical framework for superfluid-mediated domain wall motion and proposes a reconfigurable spin transistor based on this phenomenon.

Findings

Analytical expressions for domain wall motion derived

Micromagnetic simulations support the theory

Potential for low-dissipation spintronic applications

Abstract

We theoretically investigate the transfer of angular momentum between a spin superfluid and a domain wall in an exchange coupled easy-axis and easy-plane magnetic insulator system. A domain wall in the easy-axis magnet absorbs spin angular momentum via disrupting the flow of a superfluid spin current in the easy-plane magnet. Focusing on an open geometry, where the spin current is injected electrically via a nonequilibrium spin accumulation, we derive analytical expressions for the resultant superfluid-mediated motion of the domain wall. The analytical results are supported by micromagnetic simulations. The proposed phenomenon extends the regime of magnon-driven domain-wall motion to the case when the magnons are condensed and exhibit superfluidity. Furthermore, by controlling the pinning of the domain wall, we propose a realization of a reconfigurable spin transistor. The long-distance dissipationless character of spin superfluids can thus be exploited for manipulating soliton-based memory and logic devices.