Modeling of ultrafast X-ray induced magnetization dynamics in magnetic multilayer systems

TL;DR

This paper presents a simulation tool to model ultrafast X-ray induced magnetization dynamics in ferromagnetic multilayers, specifically Co/Pt systems, aligning with experimental observations and emphasizing electronic processes in demagnetization.

Contribution

The study introduces a new simulation approach for nanoscopic electronic processes in X-ray irradiated magnetic multilayers, validated against experimental data.

Findings

Magnetic scattering from cobalt decreases within femtoseconds due to electronic effects.

Simulation results match experimental demagnetization trends.

Electronic processes dominate X-ray induced demagnetization below damage threshold.

Abstract

In this work, we report on modelling results obtained with our recently developed simulation tool enabling nanoscopic description of electronic processes in X-ray irradiated ferromagnetic materials. With this tool, we have studied the response of Co/Pt multilayer system irradiated by an ultrafast extreme ultraviolet pulse at the M-edge of Co (photon energy $\sim$ 60 eV). It was previously investigated experimentally at the FERMI free-electron-laser facility, using the magnetic small-angle X-ray scattering technique. Our simulations show that the magnetic scattering signal from cobalt decreases on femtosecond timescales due to electronic excitation, relaxation and transport processes both in the cobalt and in the platinum layers, following the trend observed in the experimental data. The confirmation of the predominant role of electronic processes for X-ray induced demagnetization in the regime below the structural damage threshold is a step towards quantitative control and manipulation of X-ray induced magnetic processes on femtosecond timescales.