Energetic analysis of disorder effects in an artificial spin ice with dipolar interactions

TL;DR

This study investigates how quenched disorder in island length affects the magnetic ordering in artificial spin ice, revealing that disorder can induce mixed states and ferromagnetic dominance even in regimes favoring antiferromagnetism.

Contribution

It introduces a numerical analysis of disorder effects in artificial spin ice, focusing on how length disorder influences magnetic orderings near the ice regime.

Findings

Weak disorder leads to intermediate or mixed magnetic states.

Strong disorder causes ferromagnetic plaquettes to dominate.

Disorder impacts the system's ability to thermalize and order.

Abstract

We study the effect of quenched disorder in square artificial spin ice by means of numerical simulations. We introduce disorder in the length of magnetic islands using two kinds of distributions: Gaussian and uniform. As the system behavior depends on its geometrical parameters, we focus on studying it in the proximity of the ice regime which is quite difficult to thermalize both in experiments and simulations. We show how length disorder affect the antiferromagnetic and (locally) ferromagnetic ordering, by inducing the system, in the case of weak disorder, to intermediate or mix states. Moreover, in the case of strong disorder, ferromagnetic plaquettes prevail regardless of whether the mean length of the islands corresponds to an antiferromagnetic ordering.