Ultrafast magnetization dynamics explored with X-rays

Abstract:

In the BMBF financed DynaMax Project we set up a new endstation at the FemtoSpeX Slicing facility of BESSY II. Here we study ultrafast dynamics in magnetic materials and explore their underlying mechanism with X-rays. X-rays allow for an element- and state-specific probe of magnetic and electronic structure with controlled depth sensitivity. Our In-situ grown 4f and 3d magnets, their multilayers and alloys offer a wide playground to investigate fundamental processes as well as first conceptional approaches for magnetic applications.

Further Details on the Project:

At the FemtoSpex Slicing beamline at the synchrotron facility Bessy II we set up new endstation to explore ultrafast magnetization dynamics. This chamber enables X-ray absorption, reflectivity and diffraction studies with variable polarization and in magnetic fields up to 1.5 Tesla. At the slicing beamline we use intrinsically synchronized 50-fs-laser and 100-fs-X-ray pulses for pump-probe experiments. X-ray magnetic circular dichroism (XMCD) and X-ray magnetic resonant diffraction (XMRD) allow for probing ferro- as well as antiferromagnetic dynamics. Since magnetization dynamics critically depend on the magnetic material, sample composition and morphology, part of the new setup is a combined Molecular Beam Epitaxy (MBE) and Magnetron Sputter deposition chamber, installed at the neighboring PM3 beamline. Here we design and grow high-quality magnetic samples and characterize them statically with X-ray. For special experiments with both, high energy and time resolution our for studies that require X-ray energies not provided by the FemtoSpex Slicing beamline, we apply for beamtimes at the free electron lasers FLASH and European XFEL.

DynaMaX endstation at FemtoSpeX Slicing beamline of BESSYII

The BMBF financed DynaMax endstation

https://www.helmholtz-berlin.de/pubbin/igama_output?modus=einzel&sprache=de&gid=2229&typoid

in combination with the Slicing beamlime

https://www.helmholtz-berlin.de/pubbin/igama_output?modus=einzel&sprache=de&gid=1644&typoid

is a unique setup to study non-equilibrium dynamics in solids. It merges different X-ray techniques using variable polarization, magnetic fields and experimental geometry with fs time-resolution in an energy range of 410‑1330 eV. The magnetic field with variable orientation and with fields up to 1.5 Tesla is realized by a fast vector magnet. With these setting experiments utilizing time-resolved absorption, XMLD, XMCD, NEXAFS, reflection, diffraction and magnetic scattering can be performed. Currently we work on the BMBF financed follow up project of DynaMax. In this project, called MadMaXs, we develop a new time and spatially resolved detector for the DynaMax FemtoSpeX endstation.