The Landau-Lifshitz equation in atomistic models

TL;DR

This paper discusses the application and limitations of the Landau-Lifshitz equation within atomistic spin dynamic models, which are crucial for understanding ultrafast magnetisation phenomena.

Contribution

It provides an overview of ASD models based on the LL equation and examines their role and limitations in modeling ultrafast magnetisation dynamics.

Findings

ASD models effectively predict thermally induced magnetisation switching.

The LL equation's applicability in atomistic models has specific limitations.

ASD models enhance understanding of ultrafast magnetic phenomena.

Abstract

The Landau-Lifshitz (LL) equation, originally proposed at the macrospin level, is increasingly used in Atomistic Spin Dynamic (ASD) models. The models are based on a spin Hamiltonian featuring atomic spins of fixed length, with the exchange introduced using the Heisenberg formalism. ASD models are proving a powerful approach to the fundamental understanding of ultrafast magnetisation dynamics, including the prediction of the thermally induced magnetisation switching phenomenon in which the magnetisation is reversed using an ultrafast laser pulse in the absence of an externally applied field. The paper outlines the ASD model approach and considers the role and limitations of the LL equation in this context.