Influence of domain wall interactions on nanosecond switching in magnetic tunnel junctions

TL;DR

This study demonstrates how domain wall stray fields in magnetic tunnel junctions influence and can accelerate nanosecond magnetization switching, with evidence from imaging and simulations.

Contribution

It provides microscopic evidence of domain wall stray fields affecting switching speed in magnetic trilayers, highlighting a new internal bias mechanism.

Findings

Stray fields from domain walls lower the nucleation barrier.

Internal bias fields can enhance switching speed.

Micromagnetic simulations confirm experimental observations.

Abstract

We have obtained microscopic evidence of the influence of domain wall stray fields on the nanosecond magnetization switching in magnetic trilayer systems. The nucleation barrier initiating the magnetic switching of the soft magnetic Fe20Ni80 layer in magnetic tunnel junction-like FeNi/Al2O3/Co trilayers is considerably lowered by stray fields generated by domain walls present in the hard magnetic Co layer. This internal bias field can significantly increase the local switching speed of the soft layer. The effect is visualized using nanosecond time- and layer-resolved magnetic domain imaging and confirmed by micromagnetic simulations.