Extended x-ray characteristic fluorescence fine structure above the K-edges of Ni, Cu, NiCu, and NiO by fast electron excitation

The extended x-ray fluorescence fine structure (EXFLUFS) above the Ni and Cu K-edge of Ni, Cu, NiCu and NiO using the appearance potential regime by fast electron excitation was measured by means of scanning electron microscope with Si (Li) crystal detector and multichannel analyzer in the raster or single mode. The conventional extended x-ray absorption fine structure (EXAFS) type analysis was made in order to obtain the structural information. The Fourier filtered peak fitting with the phase shift correction from Teo & Lee gives the interatomic distances, which agree well with crystallographic and EXAFS data. The fitting results of experimental data suggest that conventional EXAFS phase shift correction can be safely used for EXFLUFS analysis with a little correction, if needed. The intensities of EXFLUFS peaks differ from that of EXAFS case, probably, because of non-dipole excitation, as well as the elastic scattering of primary electron before and after the inelastic scattering event. The EXFLUFS method is a bulk sensitive method which ensures several orders higher spatial resolution than in the synchrotron x-ray radiation case, as well as allows the deep core excitation in the wide energy range.