Ferromagnetic resonance response in square artificial spin ice: roles of geometry in vertex dynamics and magnetic configurations

Abstract

Artificial spin ice (ASI) represents a class of uniquely structured superlattices comprising geometrically arranged interacting nanomagnets. This arrangement facilitates the exploration of magnetic frustration phenomena and related spin wave dynamics, contributing to the field of magnonics. In this work, we present a compressive study of spin wave dynamics in square ASI lattices using micromagnetic simulations, explicitly focusing on ferromagnetic resonance (FMR) and oscillation modes. We investigate how variations in the aspect ratio of nanomagnets dimensions influence magnetic excitations in both saturated and remanent states. We analyze the frequency variations of FMR peaks corresponding to edges and bulk oscillation modes in relation to both magnetic configuration and nanomagnets dimensions. We emphasize the remanent state of square ASI vertex configurations, particularly focusing on their characteristic energy states (Type I, Type II, Type III, and Type IV), while detailing how symmetries influence oscillation modes. We observe distinct FMR responses originating from vertices, exhibiting unique characteristics for each energy state. Our results offer a potential method of utilizing the FMR technique to identify energy states in ASI systems.