Dynamical x-ray diffraction from an icosahedral Al-Pd-Mn quasicrystal
Over the past ten years the quality and size of aperiodic crystals has steadily increased. This raises some interesting issues regarding the limitations of structural perfection attainable in non periodic solids. Results from a coherent x-ray diffraction experiment on an icosahedral Al-Pd-Mn quasicrystal, as well as direct evidence of dynamical diffraction of x-rays from quasicrystals are presented. In particular, the anomalous transmission of x-rays (the Borrmann effect), the Borrmann Fan, and Pendellosung fringe patterns have been observed. These measurements show that nearly perfect quasicrystals may be grown to centimeter-size dimensions thus implying the feasibility of performing a large range of measurements based on the study of perfect crystals. In addition, the dynamical theory of diffraction is applicable to the study of aperiodic crystals.