Thermal excitations within and among mesospins in artificial spin ice

TL;DR

This study combines experimental and numerical methods to investigate thermal excitations in artificial spin ice, revealing temperature-dependent magnetic fluctuations and their tunability by interaction strength.

Contribution

It provides new insights into thermal behaviors within and among mesospins in artificial spin ice, highlighting the tunability of fluctuations by interaction strength.

Findings

Decrease in magnetization with temperature

Susceptibility peak indicating spin flipping

Thermal fluctuations are tunable by interaction strength

Abstract

We provide experimental and numerical evidence for thermal excitations within and among magnetic mesospins, forming artificial spin ice structures. At low temperatures, a decrease in magnetization and increase in susceptibility is observed with increasing temperature, interpreted as an onset of thermal fluctuations of the magnetic texture within the mesospins. At elevated temperatures a pronounced susceptibility peak is observed, related to thermally induced flipping of the mesospins and a collapse of the remanent state. The fluctuations, while occurring at distinct length- and energy-scales, are shown to be tunable by the interaction strength of the mesospins.