Spin Waves in a Periodically Layered Magnetic Nanowire

TL;DR

This paper presents a theoretical approach to determine the spectrum and damping of spin waves in cylindrical layered magnetic nanowires, aiding the design of magnonic crystals with specific band-gap properties.

Contribution

It introduces a simple theoretical derivation for spin wave spectra in cylindrical magnonic crystals using an effective medium approximation, highlighting differences from volume-averaged parameters.

Findings

Derived formulae for spin wave dispersion in the first allowed band.

Showed how effective magnetic parameters depend on individual layer properties.

Provided a method for designing magnonic crystals with targeted band-gaps.

Abstract

We report a simple theoretical derivation of the spectrum and damping of spin waves in a cylindrical periodically structured magnetic nanowire (cylindrical magnonic crystal) in the "effective medium" approximation. The dependence of the "effective" magnetic parameters upon the individual layer parameters is shown to be different from the arithmetic average over the volume of the superlattice. The formulae that are obtained can be applied firstly in the description of spin wave dispersion in the first allowed band of the structure; and secondly in the design of a magnonic crystal with band-gaps in an arbitrary part of the spin wave spectrum.