The local atomic and electronic structure of quasicrystal i-Al65Cu23Fe12 powder

Abstract

This work presents an experimental and theoretical study of the atomic and electronic structures of the icosahedral Al65Cu23Fe12 quasicrystalline (QС) powder. The i-Al65Cu23Fe12 QС powder was investigated using X-ray diffraction, scanning electron microscopy, Mössbauer spectroscopy, X-ray absorption spectroscopy (XANES and EXAFS) and X-ray photoelectron spectroscopy. It was found that the i-Al65Cu23Fe12 quasicrystal surface consisted of an oxidized shell of Al2O3 and Cu2O, whereas the bulk fraction consisted of icosahedral Al65Cu23Fe12 quasicrystal and cubic β-Al(Cu0.5Fe0.5) phases. The proposed theoretical model of the structure of i-Al65Cu23Fe12 QC, based on the transformation of the crystalline analogue of Al7Cu2Fe, has good agreement with the experimental structural data obtained from EXAFS and XANES analysis. The electronic structure of the top of the valence band and the bottom of the conduction band of the i-Al65Cu23Fe12 QC was investigated using X-ray photoelectron spectroscopy, analysis of XANES, and ab initio calculations.