Magnonic band gaps in waveguides with a periodic variation of the saturation magnetization

TL;DR

This paper investigates how periodic variations in saturation magnetization in a permalloy waveguide create magnonic band gaps, with analysis of their origins and control mechanisms for potential spin-wave device applications.

Contribution

It introduces a micromagnetic analysis of spin-wave band gaps in a magnonic crystal with periodic saturation magnetization variation, highlighting control over gap properties.

Findings

Frequency band gaps are observed in spin-wave transmission spectra.

Band gaps result from overlap of fundamental and higher order mode gaps.

Control of gap properties is achieved through magnetization variation and modulation level.

Abstract

We present a micromagnetic analysis of spin-wave propagation in a magnonic crystal realized as a permalloy spin-wave waveguide with a spatial periodical variation of its saturation magnetization. Frequency band gaps were clearly observed in the spin-wave transmission spectra and their origin is traced back to an overlap of individual band gaps of the fundamental and the higher order spin-wave width modes. The control of the depth, width and the position in frequency and space of the rejection band gaps by the width areas with a reduced magnetization and by the modulation level, are discussed in this study.