Dipole-exchange spin waves in Fibonacci magnetic multilayers

TL;DR

This paper investigates the complex spin wave spectra in Fibonacci quasiperiodic magnetic multilayers, revealing band splitting, mode mixing, and fractal spectral features due to dipolar interactions and non-periodic structure.

Contribution

It introduces a microscopic model to analyze dipole-exchange spin waves in Fibonacci multilayers, extending previous magnetostatic studies with detailed spectral predictions.

Findings

Frequency band splitting observed

Mode mixing influenced by spacer thickness

Fractal spectrum characteristics identified

Abstract

A microscopic model is employed to calculate the spectrum of spin waves in quasiperiodic magnetic multilayers in the dipole-exchange regime. Results are presented for structures in which thin ferromagnetic films are separated by non-magnetic spacers following a Fibonacci sequence and extend previous magnetostatic calculations. The results show the splitting of the frequency bands and the mode mixing caused by the dipolar interaction between the films as a function of spacer thickness, as well as the fractal aspect of the spectrum induced by the non-periodic aspect of the structure.