Role of Bound Magnon in Magnetic Domain Wall Motion

TL;DR

This paper presents a quantum model showing that bound magnons significantly influence magnetic domain wall motion under spin currents, revealing new insights into DW dynamics and spin transfer mechanisms.

Contribution

It introduces the concept that bound magnons act as free particles with inertia, enabling full spin transfer and unique DW motion characteristics.

Findings

Bound magnons are zero modes that dominate DW dynamics.

Full spin transfer occurs via bound magnons, leading to adiabatic DW velocity.

Spin waves decouple from DW, with no Doppler shift observed.

Abstract

We report on a quantum description of the domain wall (DW) motion under a spin current. A bound magnon, which is the zero mode of DW, is found to play a dominant role in DW dynamics. The bound magnon acquires its inertia by the hard axis anisotropy and is a free particle even under the spin current. The full transfer of spin angular momentum from the spin current to DW via the bound magnon leads to the DW motion with the adiabatic velocity, decoupling of spin waves from DW, and no Doppler shift in spin waves.