Resonant X-ray diffraction study of frustrated germanium ferrite thin films

Frustrated magnetic materials can show unconventional spin configurations such as quantum spin liquid states and monopole excitations in spin ices. These phenomena are observed on uniformly frustrated lattices such as triangular, kagome or pyrochlore types, where all nearest neighbor interactions are equivalent. GeFe2O4 crystallizes in a direct spinel structure for which the magnetic 3d6 Fe2+ are located in the Oh sites and thus form a pyrochlore sublattice. If these phases are relatively well understood in bulk, their structure in thin films (cationic distribution, positions of the atoms, and oxidation states) is still completely unknown. X-ray resonant diffraction is the best adapted technique for this aim, if not the only available one, for it allows discrimination between the involved cations and necessitates small amounts of matter.