Ultrafast dynamics of moments in bulk ferromagnets

TL;DR

This paper introduces a comprehensive model combining Landau-Lifshitz-Bloch equations, a quantum thermostat, and a two-temperature model to study ultrafast magnetic dynamics in ferromagnets, validated on nickel, cobalt, and iron.

Contribution

It presents a novel integrated modeling approach for ultrafast magnetic dynamics, including analysis of susceptibility tensor components under different magnetic field conditions.

Findings

Model accurately describes ultrafast magnetization dynamics in selected materials.

Off-diagonal susceptibility components show distinct features with external magnetic fields.

The approach offers insights into magnetic response at ultrafast timescales.

Abstract

A robust and efficient model for investigating the ultrafast dynamics of magnetic materials excited by laser pulses has been created, integrating dynamic Landau-Lifshitz-Bloch equations with a quantum thermostat and a two-temperature model. The model has been successfully applied to three archetypal materials in the literature: nickel, cobalt, and iron. Additionally, analysis of the ultrafast dynamic susceptibility tensor indicates that off-diagonal components display specific features depending on whether a continuous external magnetic field is present.