Diffuse scattering of decagonal Al70Ni15Co15 measured with synchrotron radiation

Abstract Diffuse scattering of the thermodynamically stable decagonal quasicrystal (QC) Al70Ni15Co15 has been measured at a synchrotron radiation source. Perpendicular to the unique ‘periodic’ direction there is an alternating sequence of ‘Bragg’ and (modulated) diffuse layers. Within the zeroth Bragg layer, strong diffuse streaks and diffuse satellite reflections, as well as very weak and slowly varying diffuse scattering, were measured up to high values of Q. Satellites and diffuse streaks, already known from precession photographs, were explored in the q-scan mode yith a step width of 0.01 in h and k (pseudo-monoclinic setting with a∗ = 0.081 08 A−1, b∗ = 0.081 09 A−1 in the QC plane, c∗ = 0.245 16 A−1 in the periodic direction, y = 72°). The positions, but not the intensities of all registered satellite reflections obey an overall tenfold symqetry around the Bragg reflection. The satellite vector magnitude [sbnd]qs[sbnd] = 3.3 × 10 −2 A−1 corresponds to a translational superperiod of the QC substructu...