Structural dynamics during laser-induced ultrafast demagnetization

Abstract

Despite two decades of intense research, the origin of ultrafast demagnetization remains disputed. Here, the authors employ resonant magnetic x-ray reflectivity to follow simultaneously magnetization and structural dynamics at the BESSY femtoslicing source. They find that significant changes in nonmagnetic x-ray reflectivity accompany the subpicosecond demagnetization, which can be modeled as a variation of film thickness. Their simulations further show that the higher photon flux and energy resolution provided by x-ray free electron lasers will yield decisive data to differentiate between different mechanisms proposed to govern ultrafast demagnetization dynamics.