ION CHANNELING IN T-PHASE QUASI-CRYSTALS - AN INVESTIGATION BY RUTHERFORD BACKSCATTERING AND PARTICLE INDUCED X-RAY-EMISSION

The channeling properties of a T-phase Al62Cu20Co15Si3 quasicrystal are investigated in a Rutherford backscattering study employing 2 MeV He-ions. Besides axial channeling along the decagonal axis, also planar channeling is observed in planes having the decagonal axis in common and showing the decagonal symmetry of the quasicrystal. Besides a system of main planes, various planes exhibiting only weak channeling properties are observed; they correspond to linear arrangements of vertices in a two-dimensional Penrose grid, demonstrating the close relationship between T-phase quasicrystals and Penrose pattern. Rutherford backscattering (RBS) has also been used to study the decoration of the T-phase structure by Co/Cu- and Al/Si-atoms; in addition, particle induced X-ray emission PIXE served to distinguish between Co- and Cu-atoms. The experimental data are compared with channeling computer simulations on a model T-phase quasicrystal proposed by Steurer and Kuo [6].