AN INVESTIGATION ON POLYCRYSTALLINE BORON AND BORON-CONTAINING METALLIC GLASSES BY SEELFS

The slow electron energy-loss spectra in a reflection mode recorded above a core-level, known as the surface extended energy-loss fine structure (SEELFS), can give detailed local surface structural information of solids. This work reports for the first time the investigation of the role the boron atoms play in polycrystalline boron, Fe80B20 and Fe78.5 Si5B16.5 samples by using this technique. The oscillating structures were up to 300 eV above the boron K-edge. With the program daveloped in this laboratory, the radial distribution functions around the excited site were obtained by analyzing the SEELFS data. After phase-shift correction, the nearest-neighbor bondlengths of surface atoms were found: 1.57 ? for polycrystalline boron, 2.14 ? for Fe80B20 and 2.12 ? for Fe78.5Si5B16.5</sub. Factors influencing the calculations are discussed and the total error has been estimated as 0.05-0.08 ? for central atoms with low atomic number. For the SEELFS spectra in the derivative mode, it is difficult to obtain other structural parameters, e.g. coordination number, factor of atom disorder, etc. Therefore, other mode must be considered.