Eddy current effects in the magnetization dynamics of ferromagnetic metal nanoparticles

TL;DR

This paper presents an analytical model for ferromagnetic metal nanoparticles that incorporates eddy current effects into magnetization dynamics, highlighting their significant influence on phenomena like precessional switching.

Contribution

The authors develop a coupled LLG-Maxwell model that explicitly accounts for conductivity-induced eddy currents in ferromagnetic nanoparticles, advancing understanding of their magnetization behavior.

Findings

Eddy currents significantly alter magnetization dynamics in metallic nanoparticles.

The model predicts differences between metallic and dielectric nanoparticle behavior.

Eddy currents impact the precessional switching process.

Abstract

We develop an analytical model for describing the magnetization dynamics in ferromagnetic metal nanoparticles, which is based on the coupled system of the Landau-Lifshitz-Gilbert (LLG) and Maxwell equations. By solving Maxwell's equations in the quasi-static approximation and finding the magnetic field of eddy currents, we derive the closed LLG equation for the magnetization that fully accounts for the effects of conductivity. We analyze the difference between the LLG equations in metallic and dielectric nanoparticles and show that these effects can strongly influence the magnetization dynamics. As an example illustrating the importance of eddy currents, the phenomenon of precessional switching of magnetization is considered.