High resolution dynamic imaging of the delay- and tilt-free motion of N\'eel domain walls in perpendicularly magnetized superlattices

TL;DR

This study uses high-resolution, time-resolved imaging to investigate the rapid, tilt-free motion of Neel domain walls in magnetic superlattices, revealing negligible inertia and no incubation times.

Contribution

It provides the first direct observation of tilt-free, inertia-negligible domain wall motion at high temporal resolution in perpendicularly magnetized superlattices.

Findings

Domain walls move at 50-100 m/s under current and field.

No incubation time or inertia observed in domain wall motion.

Domain walls do not tilt during short pulse motion.

Abstract

We report on the time-resolved investigation of current- and field-induced domain wall motion in perpendicularly magnetized microwires exhibiting asymmetric exchange interaction by means of scanning transmission x-ray microscopy using a time step of 200 ps. Dynamical domain wall velocities on the order of 50-100 m s$^{-1}$ were observed. The improvement in the temporal resolution allowed us to observe the absence of incubation times for the motion of the domain wall, together with indications for a negligible inertia. Furthermore, we observed that, for short current and magnetic field pulses, the magnetic domain walls do not exhibit a tilting during its motion, providing a mechanism for the fast, tilt-free, motion of magnetic domain walls.