Freitag, 29. Mai 2026 17:00 Uhr X-ray Eyes on Magnetism: Probing Dynamics, Order, and Function in Materials from Molecules to Permanent Magnets
Prof. Dr. Katharina Johanna Ollefs, Kirchhoff-Institut für Physik, Universität Heidelberg X-ray Eyes on Magnetism: Probing Dynamics, Order, and Function in Materials from Molecules to Permanent Magnets Prof. Dr. Katharina Johanna Ollefs Kirchhoff-Institut für Physik, Universität Heidelberg Polarization-dependent x-ray absorption spectroscopy (XAS) has become one of the most versatile probes for magnetism because it combines element, orbital and spin selectivity with the possibility of imaging, ultrafast pump–probe measurements and operation under diverse sample conditions. In this talk I will demonstrate how to employ these capabilities to observe the atomic-scale arrangements that underlie the functional response of magnetic materials and, ultimately leading to learn how to design them. In my talk I am going to illustrate how external stimuli—temperature, static magnetic or electric fields, optical and microwave excitation, or pressure—can drive and modify phase transitions in magnetic systems. In addition, I will present nanoscale imaging of functional magnetic materials. These experiments allow to disentangle intrinsic magnetic parameters from contributions arising from micro- and nanostructure, a prerequisite for rational design of magnetocaloric, spintronic and permanent-magnet alloys.
