Super-Diffusive Spin-Transport as a Mechanism of Ultrafast Demagnetization

TL;DR

This paper introduces a semi-classical super-diffusive electron transport model that explains ultrafast laser-induced demagnetization in nickel within 200 femtoseconds, without requiring angular momentum dissipation.

Contribution

It presents a novel semi-classical transport model for femtosecond demagnetization that accurately captures experimental results without additional dissipation mechanisms.

Findings

Demagnetization in Ni occurs within 200 fs due to super-diffusive spin-polarized electron transport.

The model accounts for multiple metal layers and exact collision timing.

No angular momentum dissipation needed to explain ultrafast demagnetization.

Abstract

We propose a semi-classical model for femtosecond-laser induced demagnetization due to spin-polarized excited electron diffusion in the super-diffusive regime. Our approach treats the finite elapsed time and transport in space between multiple electronic collisions exactly, as well as the presence of several metal films in the sample. Solving the derived transport equation numerically we show that this mechanism accounts for the experimentally observed demagnetization within 200fs in Ni, without the need to invoke any angular momentum dissipation channel.