AmorphousAl90FexCe10−xalloys: X-ray absorption analysis of the Al, Fe and Ce local atomic and electronic structures

Abstract

X-ray-absorption fine structure (XAFS) above the Fe K edge, the Ce ${L}_{3}$ edge, and the Al K edge in amorphous ${\mathrm{Al}}_{90}{\mathrm{Fe}}_{x}{\mathrm{Ce}}_{10\ensuremath{-}x}$ $(x=3,$ 5, and 7) alloys have been measured and analyzed. Quantitative analyses of the Fe K-edge and Ce ${L}_{3}$-edge extended XAFS spectra are limited to local structure parameters of the first coordination sphere. Comparison of experimental x-ray-absorption near-edge structure (XANES) spectra with theoretical multiple-scattering (MS) XANES spectra for model compounds, such as crystalline ${\mathrm{FeAl}}_{6}$ and ${\mathrm{CeAl}}_{4},$ allows one to determine the local structure around the aluminum, iron, and Ce sites in ternary amorphous alloys. Using the theoretical MS approach, we show that the Fe and Al K-edge XANES are sensitive to the structure of coordination spheres, which extend up to nearly 4.4 and 3.3 \AA{}, respectively. The Ce ${L}_{3}$-edge XANES, on the other hand, is sensitive to the structure that extends up to 3.15 \AA{}.