Current-Driven Motion of Magnetic Domain Wall with Many Bloch Lines

TL;DR

This paper theoretically investigates how the presence of many Bloch lines affects the current-driven motion of magnetic domain walls, revealing a significant reduction in the critical current needed for motion due to Bloch lines.

Contribution

It introduces a theoretical analysis showing that Bloch lines dramatically alter the current-velocity behavior of domain walls, reducing the critical current density compared to skyrmions.

Findings

Critical current density is reduced by the Gilbert damping coefficient ven compared to skyrmions.

Bloch lines significantly change the current-velocity characteristic of domain wall motion.

Contrasts with magnetic field-driven motion where Bloch lines decrease mobility.

Abstract

The current-driven motion of a domain wall (DW) in a ferromagnet with many Bloch lines (BLs) via the spin transfer torque is studied theoretically. It is found that the motion of BLs changes the current-velocity ($j$-$v$) characteristic dramatically. Especially, the critical current density to overcome the pinning force is reduced by the factor of the Gilbert damping coefficient $\alpha$ even compared with that of a skyrmion. This is in sharp contrast to the case of magnetic field driven motion, where the existence of BLs reduces the mobility of the DW.