Spatial distribution of spin-wave modes in cylindrical nanowires of finite aspect ratio

TL;DR

This paper investigates the spatial structure of spin-wave modes in cylindrical nanowires with finite aspect ratios using simulations and analytical models, revealing discrete spectra and edge-localized modes.

Contribution

It provides a combined simulation and analytical approach to characterize spin-wave modes and their dispersion in finite aspect ratio nanowires, including edge effects.

Findings

Discrete spectrum of standing and localized edge modes identified

Extended dispersion relation for spin waves in cylinders derived

Localized dipole-exchange modes at edges are always present

Abstract

The spin wave modes of cylindrical nanowires of moderate diameter-to-length ratio are investigated in this article. Based on three dimensional simulations and analytical calculations we determine the spatial structure of the modes. We show that standing spin waves and localized edge modes form the discrete spectrum of the nanowires. Using a simple analytical model we infer an extended dispersion relation for spin waves in cylinders. Considering the variation of the demagnetizing (internal) field we show that the localized dipole-exchange modes at the edges are always present.