Sculpting the Spin-Wave Response of Artificial Spin Ice via Microstate Selection

TL;DR

This study investigates how the magnetic microstate in artificial spin ice influences its spin-wave spectra, revealing high tunability and potential for reconfigurable magnonic devices through micromagnetic simulations.

Contribution

It provides a detailed analysis of the microstate dependence of spin-wave spectra in honeycomb ASI, highlighting the role of symmetry and defect chirality in spectral tuning.

Findings

Spin-wave spectra are highly tunable via microstate manipulation.

Mode shifting and activation are achieved by reversing nanoislands.

Symmetries and defect chirality significantly influence high-frequency response.

Abstract

The spin-wave dynamics of the ferromagnetic nanoarrays termed artificial spin ice (ASI) are known to vary depending on their magnetic microstate. However, little work has been done to characterise this relationship. Recent advances in control over the magnetic configuration of ASI bring designs harnessing the interplay between spin-wave eigenmodes and the microstate within reach, offering diverse applications including reconfigurable magnonic crystals, microwave filters and microstate read-out probes. These designs hinge on a strong understanding of the underlying spin wave-microstate correspondence. Here, we analyse the effects of the magnetic microstate on spin-wave spectra of honeycomb ASI systems via micromagnetic simulation. We find the spin-wave spectrum to be highly-tunable via the microstate to an enhanced degree relative to existing magnonic crystals, with mode shifting and (de)activation realised by reversing individual nanoislands. Symmetries of ASI systems and the chirality of magnetic defects are found to play important roles in determining the high-frequency response.