Current Induced Fingering Instability in Magnetic Domain Walls

TL;DR

This paper investigates how current-induced spin transfer torque causes fingering instabilities in magnetic domain walls, revealing that the instability depends on the domain wall motion direction and is driven by non-adiabatic effects.

Contribution

It demonstrates the role of non-adiabatic spin transfer torque in causing shape instabilities in magnetic domain walls under current.

Findings

Current density gradients can stabilize or destabilize domain walls.

Finger-like patterns form depending on domain wall motion direction.

Non-adiabatic spin transfer torque is key to the instability mechanism.

Abstract

The shape instability of magnetic domain walls under current is investigated in a ferromagnetic (Ga,Mn)(As,P) film with perpendicular anisotropy. Domain wall motion is driven by the spin transfer torque mechanism. A current density gradient is found either to stabilize domains with walls perpendicular to current lines or to produce finger-like patterns, depending on the domain wall motion direction. The instability mechanism is shown to result from the non-adiabatic contribution of the spin transfer torque mechanism.