Thermally induced magnetic relaxation in square artificial spin ice

TL;DR

This study investigates the thermally induced magnetic relaxation in square artificial spin ice, revealing that relaxation times follow the Vogel-Fulcher law and can be controlled through nano-lithography, offering insights into collective magnetic dynamics.

Contribution

The paper demonstrates control over relaxation dynamics in artificial spin ice and shows that these dynamics follow specific temperature-dependent laws, advancing understanding of mesoscopic magnetic systems.

Findings

Relaxation times follow the Vogel-Fulcher law.

Relaxation process described by Kohlrausch law.

Control over interaction strength via nano-lithography.

Abstract

The properties of natural and artificial assemblies of interacting elements, ranging from Quarks to Galaxies, are at the heart of Physics. The collective response and dynamics of such assemblies are dictated by the intrinsic dynamical properties of the building blocks, the nature of their interactions and topological constraints. Here we report on the relaxation dynamics of the magnetization of artificial assemblies of mesoscopic spins. In our model nano-magnetic system - square artificial spin ice - we are able to control the geometrical arrangement and interaction strength between the magnetically interacting building blocks by means of nano-lithography. Using time resolved magnetometry we show that the relaxation process can be described using the Kohlrausch law and that the extracted temperature dependent relaxation times of the assemblies follow the Vogel-Fulcher law. The results provide insight into the relaxation dynamics of mesoscopic nano-magnetic model systems, with adjustable energy and time scales, and demonstrates that these can serve as an ideal playground for the studies of collective dynamics and relaxations.