Local Structures of Fe<sub>0.08</sub>Co<sub>0.92</sub> Studied by X-ray Fluorescence Holography

At room temperature, pure Co has a hexagonal close-packed (HCP) structure. When several percent of Fe is doped into crystal, it changes to the face-centered cubic (FCC) However, not clear why FCC structure in FexCo1−x system so stable even with small amounts concentration. Therefore, we carried out X-ray fluorescence holography (XFH) on Fe0.08Co0.92 single crystal visualize three-dimensional atomic images around both and atoms. The intensities reconstructed by XFH atoms at 100 300 K are inversely proportional distance from emitter, those were always higher than due suppression thermal vibrations image did increase cooling unlike Fe. In particular, dependence roughly constant up 0.8 nm. This suggests that lattice Co, i.e., matrix Fe0.08Co0.92, more distorted dopant