Suppression of Standing Spin Waves in Low-Dimensional Ferromagnets

TL;DR

This study uses atomistic spin dynamics simulations to explain why standing spin wave modes are absent in thin ferromagnetic films, showing that increasing layers suppress optical branches and that a dynamical Heisenberg model captures the damping effects.

Contribution

The paper demonstrates that dynamical analysis of the Heisenberg model explains the suppression of standing spin waves in multilayer ferromagnetic films, aligning with experimental observations.

Findings

Suppression of optical spin wave branches with increasing layers.

Agreement between simulations and electron energy loss spectroscopy measurements.

Damping of standing modes explained by dynamical Heisenberg model.

Abstract

We examine the experimental absence of standing spin wave modes in thin magnetic films, by means of atomistic spin dynamics simulations. Using Co on Cu(001) as a model system, we demonstrate that by increasing the number of layers, the "optical" branches predicted from adiabatic first-principles calculations are strongly suppressed, in agreement with spin-polarized electron energy loss spectroscopy measurements reported in the literature. Our results suggest that a dynamical analysis of the Heisenberg model is sufficient in order to capture the strong damping of the standing modes.