Spontaneous Magnetic Superdomain Wall Fluctuations in an Artificial Antiferromagnet

TL;DR

This study investigates the temperature-dependent dynamics of superdomain walls in an artificial antiferromagnet, revealing a transition from ballistic to diffusive motion and an exponential slowdown below the antiferromagnetic onset temperature.

Contribution

It provides the first detailed analysis of superdomain wall fluctuations in artificial antiferromagnets using soft x-ray photon correlation spectroscopy.

Findings

Superdomain wall motion slows exponentially below the AF onset temperature.

Superdomain walls exhibit ballistic motion at low temperatures and diffusive motion at high temperatures.

The dynamics are modeled successfully with a continuous time random walk approach.

Abstract

Collective dynamics often play an important role in determining the stability of ground states for both naturally occurring materials and metamaterials. We studied the temperature dependent dynamics of antiferromagnetically ordered superdomains in a square artificial spin lattice using soft x-ray photon correlation spectroscopy. We observed an exponential slowing down of superdomain wall motion below the AF onset temperature, similar to the behavior of typical bulk antiferromagnets. Using a continuous time random walk model we show that these superdomain walls undergo low-temperature ballistic and high-temperature diffusive motions.