Mesh Size and Damped Edge Effects in Micromagnetic Spin Wave Simulation

TL;DR

This paper investigates how mesh size affects spin wave dispersion in micromagnetic simulations and proposes damping profiles to minimize reflections at device edges.

Contribution

It introduces a method to predict dispersion cutoff frequencies based on mesh size and compares damping profiles to reduce edge reflections.

Findings

Dispersion cutoff frequency depends on average mesh length.

Exponential damping profiles significantly reduce reflections.

A practical recipe for obtaining accurate dispersion relations is provided.

Abstract

We have studied the dependence of spin wave dispersion on the characteristics of the mesh used in a finite element micromagnetic simulation. It is shown that the dispersion curve has a cut off at a frequency which is analytically predictable. The frequency depends on the average mesh length used for the simulation. Based on this, a recipe to effectively obtain the dispersion relation has been suggested. In a separate study, spin wave reflections are absorbed by introducing highly damped edges in the device. However, an abrupt change in the damping parameter causes reflections. We compare damping profiles and identify an exponential damping profile as causing significantly less reflections.