Abstract Dr. Ohldag received his Ph.D. in Experimental Physics from the University of Duesseldorf (Germany) in 2002. He joined SLAC National Accelerator Laboratory in 1999 as a research assistant and became a postdoctoral researcher at SLAC in 2002. In 2005 he joined the lab as a full-time staff scientist until 2018 when he became a staff scientist at the Advanced Light Source at Lawrence Berkeley National Laboratory. His expertise is soft x-ray spectroscopy and microscopy of complex materials and devices. Dr. Ohldag has been awarded the David Shirley prize at LBNL and he is a fellow of the American Vacuum Society and the American Physical Society. In addition, Dr. Ohldag was awarded a Distinguished Lectureship by the IEEE Magnetics Society in 2017.Currently he is an editor for the Nature Partner Journal Spintronics and chair of the lectureship program of the IEEE Magnetics Society.33X-ray based spectroscopy and microscopy has been shown to be a powerful tool for the characterization of complex materials on the nanoscale. Using polarization dependent effects (dichroism) we are able to learn about magnetic, structural and electronic order, with tens of nanometer spatial resolution. In addition, so called photon-in, photon-out techniques are insensitive to the presence of external stimuli or even changes in ambient conditions, which allows us to study devices in-operando in state-of-the-art x-ray microscopes. Altogether, these features have led to the development of a strong international user community with a focus on e.g. battery devices or magnetic and electric devices. However, the feature that synchrotrons are pulsed sources of x-rays is typically less used by experimentalists. Synchrotrons operate at repetition rates up to 500 Mhz producing x-ray pulses that are less than 100 picosecond long with very little temporal jitter (~10ps). By using point detectors, e.g. Avalanche Photodiodes, and fast electronics with bandwidths of 10 Ghz or more it is then possible to follow reversible processes with about 10 picosecond time resolution.In this talk I will layout the scientific motivation of time resolved work at synchrotrons and their impact as compared to complementary dynamic studies at free electron lasers. I will then present examples of picosecond dynamics with a special focus on magnetism, e.g. spin waves in artificial nano-structures compared to spin waves in magnetosomes as produced by magnetotactic bacteria.Complex Materials at Device Relevant Time- and Length-scales- A Soft X-ray Spectromicroscopy Study Hendrik Ohldag Staff Scientist, Lawrence Berkeley National Laboratory (USA)Adjunct Professor, Department of Material Science, Stanford University (USA)Adjunct Professor, Department of Physics, University of California Santa Cruz (USA)Invited Talk: S2-2
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