Spin wave spectrum of a magnonic crystal with an isolated defect

TL;DR

This paper presents a theoretical analysis of spin wave spectra in a one-dimensional magnonic crystal with an isolated defect, demonstrating how defect modes emerge within band gaps and can be tuned by adjusting layer parameters.

Contribution

It introduces a model for defect layers in magnonic crystals and analyzes how these defects create localized modes within the band gaps, offering tunability of these modes.

Findings

Localized defect modes appear within magnonic band gaps.

The number and frequency of defect modes can be controlled by layer parameters.

Defect layers induce multiple localized modes depending on their properties.

Abstract

Real magnonic crystals - periodic magnetic media for spin wave (magnon) propagation - may contain some defects. We report theoretical spin wave spectra of a one dimensional magnonic crystal with an isolated defect. The latter is modeled by insertion of an additional layer with thickness and magnetic anisotropy values different from those of the magnonic crystal constituent layers. The defect layer leads to appearance of several localized defect modes within the magnonic band gaps. The frequency and the number of the defect modes may be controlled by varying parameters of the constituent layers of the magnonic crystal.