Neutron diffraction determination of the bulk magnetic structure of antiferromagnetic Nd2FeSr2O7 combined with x-ray microscopy

The layered perovskite Nd2SrFe2O7 (NSFO) is an antiferromagnetic (AF) material whose magnetic structure was determined using neutron powder diffraction (NPD). Recent x-ray based magnetic imaging has shown a rich network of AF domains and AF domain walls, whose analysis has led to a re-interpretation of the existing NPD results. Magnetic imaging on NSFO cleaved surfaces with X-ray Photoemission Electron Microscope (PEEM) revealed for the first time the intricate structure of the magnetic domain and domain walls (featuring loops and vortex structures) which is not compatible with the proposed interpretation of NPD data, suggesting the existence of a more intricate magnetic order than previously envisaged. The proposed WISH experiment will complement the ongoing NSFO magnetic imaging project with a deeper understanding of the AF magnetic order of the crystal, whose knowledge is key for the interpretation of the AF domain structure.