Melting artificial spin ice

TL;DR

This paper demonstrates a method to induce thermal dynamics in artificial spin ice arrays by using a material with a near-room-temperature ordering point, enabling the study of thermally active spin ice behavior.

Contribution

The authors introduce a new artificial spin ice system with real thermal dynamics by selecting a material with a low ordering temperature, allowing for temperature-dependent studies.

Findings

Confirmation of a 'pre-melting' transition below the material's intrinsic ordering temperature

Observation of temperature-dependent magnetization in different directions

Simulation agreement with experimental magnetization data

Abstract

Artificial spin ice arrays of micromagnetic islands are a means of engineering additional energy scales and frustration into magnetic materials. Despite much progress in elucidating the properties of such arrays, the `spins' in the systems studied so far have no thermal dynamics as the kinetic constraints are too high. Here we address this problem by using a material with an ordering temperature near room temperature. By measuring the temperature dependent magnetization in different principal directions, and comparing with simulations of idealized statistical mechanical models, we confirm a dynamical `pre-melting' of the artificial spin ice structure at a temperature well below the intrinsic ordering temperature of the island material. We thus create a spin ice array that has real thermal dynamics of the artificial spins over an extended temperature range.