We have observed dynamical diffraction in the  and reflections of the icosahedral quasicrystal A1PdMn in the back-reflection geometry (θB = 90 ). The x-ray fluorescence from the Al and Pd atoms exhibits strong standing wave behavior, similar to that observed in crystalline materials. The data indicate a long-range order of each species of atoms, with the coherent positions attributable to distributions of the Al and Pd, which we compare to a centrosymmetric model. We observe deviations from the model which imply small departures from inversion symmetry along the twofold symmetry axis and from the expected coherent fractions for Al.
Citation: Physical Review Letters
Pub Type: Journals
Diffraction, dynamical diffraction, icosohedral, quasicrystal, standing waves, x-ray, x-ray diffraction, x-ray standing waves