Experimental and theoretical evidences for the ice regime in planar artificial spin ices

TL;DR

This study investigates how geometric effects influence the thermodynamics of artificial spin ices, revealing that certain lattice geometries enable richer magnetic behaviors and thermal excitations, especially near the ice regime.

Contribution

It demonstrates that geometric design in artificial spin ices can induce thermally driven magnetic monopole excitations and ground state diversity, expanding understanding of their thermodynamic properties.

Findings

Rhombic lattice with aspect ratio √3 enhances thermally driven spin flips.

Thermal effects vary significantly with lattice geometry in RASI.

Certain geometries approach the ice regime, enabling new magnetic phenomena.

Abstract

In this work, we explore a kind of geometrical effect in the thermodynamics of artificial spin ices (ASI). In general, such artificial materials are athermal. Here, We demonstrate that geometrically driven dynamics in ASI can open up the panorama of exploring distinct ground states and thermally magnetic monopole excitations. It is shown that a particular ASI lattice will provide a richer thermodynamics with nanomagnet spins experiencing less restriction to flip precisely in a kind of rhombic lattice. This can be observed by analysis of only three types of rectangular artificial spin ices (RASI). Denoting the horizontal and vertical lattice spacings by a and b, respectively, then, a RASI material can be described by its aspect ratio $\gamma$=a/b. The rhombic lattice emerges when $\gamma$=$\sqrt{3}$. So, by comparing the impact of thermal effects on the spin flips in these three appropriate different RASI arrays, it is possible to find a system very close to the ice regime.