Magnetic Domain Wall Pumping by Spin Transfer Torque

TL;DR

This paper demonstrates that spin transfer torque can induce unidirectional magnetic domain wall motion, enabling long-range displacement driven by alternating current, with potential for resonant amplification via internal DW excitations.

Contribution

It introduces the concept of domain wall pumping driven by spin transfer torque and shows how internal degrees of freedom can be resonantly excited to amplify this effect.

Findings

DW moves unidirectionally under spin torque regardless of current polarity

Alternating current can induce long-range DW displacement

Resonant amplification occurs through excitation of DW internal modes

Abstract

We show that spin transfer torque from direct spin-polarized current applied parallel to a magnetic domain wall (DW) induces DW motion in a direction independent of the current polarity. This unidirectional response of the DW to spin torque enables DW pumping: long-range DW displacement driven by alternating current. Our numerical simulations reveal that DW pumping can be resonantly amplified through excitation of internal degrees of freedom of the DW by the current.