Thermal phase transitions in Artificial Spin-Ice

TL;DR

This paper models two-dimensional artificial spin ice using the sixteen vertex model, showing good agreement with experimental data and predicting a thermal phase transition that warrants further investigation of correlations in near-critical samples.

Contribution

It introduces a theoretical framework using the sixteen vertex model to describe artificial spin ice and predicts a second-order phase transition in these systems.

Findings

Excellent agreement between model and experimental vertex densities

Samples are in thermal equilibrium away from criticality

Prediction of a second-order phase transition in artificial spin ice

Abstract

We use the sixteen vertex model to describe bi-dimensional artificial spin ice (ASI). We find excellent agreement between vertex densities in fifteen differently grown samples and the predictions of the model. Our results demonstrate that the samples are in usual thermal equilibrium away from a critical point separating a disordered and an anti-ferromagnetic phase in the model. The second-order phase transition that we predict suggests that the spatial arrangement of vertices in near-critical ASI should be studied in more detail in order to verify whether they show the expected space and time long-range correlations.