Accessing low-energy magnetic microstates in symmetry-broken isolated square artificial spin ice vertices with magnetic field

TL;DR

This study explores how varying magnetic field angles in defective square artificial spin ice vertices enables access to low-energy magnetic states, revealing the influence of symmetry breaking and defects on magnetic configurations.

Contribution

It demonstrates the control of magnetic states in artificial spin ice through angle variation and defect engineering, supported by experimental and micromagnetic simulation data.

Findings

Changing the field angle stabilizes different magnetic states.

Defects break symmetry and influence energy landscape.

Experimental results align with micromagnetic simulations.

Abstract

In artificial spin ice systems, an interplay of defects and dipolar interactions is expected to play important roles in stabilizing different collective magnetic states. In this work, we investigated the magnetization reversal of individual defective square artificial spin ice vertices where defects break four-fold rotational symmetry of the system. By varying the angle between the applied field and the geometrical axis of the vertices, we observe a change in energy landscape of the system resulting into the stabilization of collective low-energy magnetic states. We also observe that by changing the angle, it is possible to access different vertex configurations. Micromagnetic simulations are performed for varying angle as well as external field, the results of which are consistent with the experimental data.