Comparison of the icosahedral andαstructures of Al-Mn-Si with the use of soft-x-ray emission spectroscopy

We have measured the soft-x-ray emission spectra of icosahedral-phase (I) Al₇₄{Mn}₂₀Si₆ and {α}-phase Al₁₀₀{Mn}₂₄Si₁₄. In addition, we present measurements of elemental Al and Si and of the solid solution Al₉₇{Si}₃$. All spectra represent emission from single-phase samples. {α}- and I-phase spectra are quite similar in overall structure. Mn is seen to play a central role in determining the local electronic structure associated with Al and Si in the ternary alloys. Analysis of the differences in the lower Al emission band of these alloys supports the idea that there is more than one Mn site in both phases. The electronic structure of Si in the two systems is anomalous. Comparisons of L-emission spectra of Al and Si in various alloys are made, and the validity of the equivalent core approximation is discussed.