Spin torque and charge resistance of ferromagnetic semiconductor $2\pi$ and $\pi$ domain walls

TL;DR

This paper investigates the charge resistance and spin torque in ferromagnetic 360 degree domain walls, revealing unique behaviors and potential for enhanced domain wall velocities compared to 180 degree walls.

Contribution

It provides the first detailed analysis of charge resistance and spin torque in 360 degree domain walls, highlighting their distinct trends and larger effects than 180 degree walls.

Findings

Charge resistance peaks at intermediate wall thickness for 360 degree walls.

Spin torque amplitude is more than twice as large in 360 degree walls.

Larger domain wall velocities are achievable with 360 degree walls.

Abstract

Charge resistance and spin torque are generated by coherent carrier transport through ferromagnetic 360 degree domain walls, although they follow qualitatively different trends than for 180 degree domain walls. The charge resistance of 360 degree domain walls reaches a maximum at an intermediate wall thickness, unlike 180 degree domain walls, whose resistance decreases monotonically with wall thickness. The peak amplitude of the spin torque and the optimal thickness of the domain wall to maximize torque for a 360 degree wall are more than twice as large as found for a 180 degree domain wall in the same material, producing a larger domain wall velocity for the 360 degree wall and suggesting unexpected nonlinearities in magnetoelectronic devices incorporating domain wall motion.