Hysteresis and Return Point Memory in Artificial Spin Ice Systems

TL;DR

This study explores hysteresis and return point memory in artificial spin ice systems, revealing how defects and disorder influence memory effects and their recovery in different lattice geometries.

Contribution

It provides new insights into how microscopic defects and disorder affect hysteresis and memory in artificial spin ice, with comparative analysis of square and kagome lattices.

Findings

Defects cause loss of return point memory in both systems.

Memory recovers rapidly in kagome ice but more gradually in square ice.

Increasing disorder enhances defect trapping and memory retention.

Abstract

We investigate hysteresis loops and return point memory for artificial square and kagome spin ice systems by cycling an applied bias force and comparing microscopic effective spin configurations throughout the hysteresis cycle. Return point memory loss is caused by motion of individual defects in kagome ice or of grain boundaries in square ice. In successive cycles, return point memory is recovered rapidly in kagome ice. Memory is recovered more gradually in square ice due to the extended nature of the grain boundaries. Increasing the amount of quenched disorder increases the defect density but also enhances the return point memory since the defects become trapped more easily.