Spin wave damping in periodic and quasiperiodic magnonic structures

TL;DR

This study explores how the arrangement of different magnetic materials in periodic and quasiperiodic structures affects the lifetime of spin wave modes, revealing that mode localization and material distribution can extend collective excitation lifetimes.

Contribution

It introduces a detailed analysis of spin wave lifetime dependence on mode distribution and structural complexity in magnonic structures, including quasiperiodic arrangements.

Findings

Lower frequency modes concentrate in Py wires due to lower FMR frequency.

Inhomogeneous mode distribution can extend spin wave lifetimes beyond volume averages.

Quasiperiodic structures show enhanced localization affecting spin wave lifetime.

Abstract

We investigated the lifetime of spin wave eigenmodes in periodic and quasiperiodic sequences of Py and Co wires. Those materials differ significantly in damping coefficients, therefore, the spatial distribution of the mode amplitude within the structure is important for the lifetime of collective spin wave excitations. Modes of the lower frequencies prefer to concentrate in Py wires, because of the lower FMR frequency for this material. This inhomogeneous distribution of amplitude of modes (with lower amplitude in material of higher damping and with higher amplitude in material of lower damping) is preferable for extending the lifetime of the collective excitations beyond the volume average of lifetimes for solid materials. We established the relation between the profile of the mode and its lifetime for periodic and quasiperiodic structures. We performed also the comparative studies in order to find the differences resulting from complexity of the structure and enhancement of localization in quasiperiodic system on the lifetime of spin waves.