Soft x-ray full-field lens-less imaging of magnetic materials: comparison between coherent resonant experiments and source to detector photon simulations

Abstract

Over the last few years, the beam coherence produced by modern synchrotrons remarkably pushed the limits of imaging. In the soft x-ray regime, full-field lens-less resonant Bragg diffraction was proved, naturally offering new opportunities in the investigation of correlated electron materials. On antiferromagnetic materials, antiphase domain walls were proposed to explain the characteristic dark lines (destructive interference) ubiquitously present. Recently, we showed that under zone plate illumination the accompanying characteristic intensity oscillations measured at the detector can be modeled by a Fresnel based approach. Here we further support our interpretations by showing how source to detector simulations perfectly match our full-field lens-less data when controlled sharp synthetic objects are used as samples. Additionally, by analytical calculations we model the expected oscillations generated at the detector as a function of the distance between the sample and the x-ray beam waist. Our results are relevant for future ptychographic experiments to beat current resolution limitations, in particular when using structured x-ray beams, or if other sources of scattering are involved.