Connecting the timescales in picosecond remagnetization experiments

TL;DR

This paper combines micromagnetic modeling and experiments to connect different timescales in femtosecond magnetization dynamics, revealing the role of nanometer-scale spin-wave packets in remagnetization.

Contribution

It introduces a simple micromagnetic model that links ultrafast demagnetization with slower collective processes, bridging different experimental regimes.

Findings

Identification of spin-wave packets on the nanometer scale.

Connection of elementary relaxation mechanisms across timescales.

Demonstration of the role of spin waves in remagnetization.

Abstract

In femtosecond demagnetization experiments, one gains access to the elementary relaxation mechanisms of a magnetically ordered spin system on a time scale of 100 fs. Following these experiments, we report a combined micromagnetic and experimental study that connects the different regimes known from all-optical pump-probe experiments by employing a simple micromagnetic model. We identify spin-wave packets on the nanometer scale that contribute to the remagnetization process on the intermediate time scale between single-spin relaxation and collective precession.