Joachim Stohr

My early scientific research focused on the development of the surface EXAFS and NEXAFS techniques for the determination of the geometric arrangement of atoms, molecules and thin organic films on surfaces. I have also been working on the development of X-ray emission spectroscopy for the atom-specific investigation of the surface chemical bond. My surface science interests then shifted to the study of orientation and relaxation phenomena at polymer surfaces, in particular, the alignment of liquid crystals on such surfaces. Today the major part of my research is concerned with magnetic materials and phenomena, in particular the study of magnetic thin films, interfaces and nanostructures. The studies are carried out with polarized synchrotron radiation which offers unique capabilities. Among them are the imaging of magnetic nanostructures with elemental, chemical and magnetic specificity, both by direct X-ray microscopy and holographic techniques. A particular exciting area are the direct observation of ultrafast (less than 1 nanosecond) magnetic processes by use of ultra-short X-ray pulses. My group is performing research at both the Stanford Synchrotron Radiation Lightsource (SSRL) and the Linac Coherent Light Source (LCLS), both located at SLAC.