Determination of the chemical valence of atoms at a heterophase interface by x-ray diffraction measurements of crystal truncation rod intensity at an atomic absorption edge

摘要

We report the application of a novel technique for determining the oxidation state of atoms at a buried interface. We have measured the energy dependence of the x-ray diffraction from an interface between an Al(sub 2)O(sub 3) substrate and a 100 nm Cr(sub 2)O(sub 3) film. As the energy of the x-rays is tuned through the Cr K absorption edge, diffracted intensity varies with the scattering power of Cr atoms at the interface. By comparing the near edge structure of the interface scattering with that of standard samples, we have determined that Cr(sup +3) is the predominant state at the interface.