Enhanced depth-resolution in multilayer nanostructures from standing-wave excited photoemission

The depth resolution for studying buried layers and interfaces in multilayer structures with photoemission can be enhanced by exciting with a standing-wave field created by reflection from a multilayer mirror substrate. Combining experiment with x-ray optical simulations can provide information on depth profiles of different chemical species and their magnetic properties. We have applied this method, using both rocking curves and sample scans over a wedge profile, to several types of samples: bare multilayers of Si/Mo and epitaxial SrTiO$_{3}$/La$_{0.7}$Sr$_{0.3}$MnO$_{3}$, and epitaxial MgO on a wedge of Fe on top of a GaAs/AlAs multilayer. Both soft x-ray excitation at the TU Dortmund DELTA facility and hard x-ray excitation at BESSY II in Berlin have been utilized, with the hard x-rays for the first time permitting the study of deeper layers and interfaces.