Valence-selective local atomic structures in inorganic materials by X-ray fluorescence holography

摘要

X-ray fluorescence holography (XFH) can be used to conduct atom-resolved structural characterization of materials around a specific element, and has been applied to various functional materials. Recently, a valence-selective function has been found by this technique by employing incident X-ray energies near an absorption edge of a specified element. In this article, the principle and experimental procedure of a valence-selective XFH and subsequent data analysis procedure using the sparse modeling approach of L-1 regression are introduced. Then, the excellent XFH results with valence-selective studies are reviewed, such as Y oxide thin film, YbInCu4 valence transition material, and Fe3O4 mixed valence material.