Seminars Archive

Ultrafast magnetism probed with x-ray free electron lasers

Abstract
Magnetism is a quantum effect at work in the macroscopic world we live in. As such it has fascinated mankind for millennia and also led to many modern-day applications, very prominently in information processing and storage. Polarized soft x-rays have been used for several decades at synchrotron light sources to obtain fascinating new insights into nanoscale magnetism. The separation of spin and orbital magnetic moments via x-ray magnetic circular dichroism (XMCD), for instance, enabled detailed insights into the interplay of magnetic interactions at the atomic level. The now available polarized soft x-ray pulses from x-ray free electron lasers with sub-100 femtoseconds duration allow us to observe the magnetic interactions at work in real time. I will show how the challenges for performing time-resolved XMCD at XFELs have recently been overcome and give an overview how such studies help to understand the fundamental speed limits for nanoscale spin motion.