Regensburg 2002 – scientific programme

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M: Metallphysik

M 26: Postersitzung

M 26.1: Poster

Thursday, March 14, 2002, 14:30–16:30, Saal C

Quasicrystals and related compounds in the Zn-Mg-RE system — •Roland Sterzel, Eckhard Uhrig, Stefan Brühne, and Wolf Assmus — Physikalisches Institut, J.W. Goethe-Universitaet Frankfurt, Robert-Mayer-Str. 2-4, D-60054 Frankfurt

We report on our work on Zn-Mg-RE (RE = Y, Er, Ho, Dy) alloys. A simple icosahedral (si) quasicrystalline Zn-Mg-Er phase with a composition far from hitherto known si Zn-Mg-RE quasicrystals is presented. A single phase sample enabled us to investigate the structure by means of X-ray and electron diffraction. Sharp reflections and only poor diffuse scattering in the diffraction patterns show that the structure of this si phase has less defects compared to other si Zn-Mg-RE quasicrystals. The structure will be discussed with respect to known icosahedral phases in these systems. Latest results on complex crystalline structures related to the Zn-Mg-RE quasicrystals (cubic R-phase, rhombohedral M-phase) are also presented.

In order to obtain high quality samples of the phases discussed, further thermoanalytical investigations in combination with scanning electron microscopy will be performed on melt-spun and annealed samples in the future.

Subsequently, structure solutions with particular focus on the reversible phase transition icosahedral to hexagonal phase will be tackled via the atomic pair distribution function (PDF) from diffraction intensities including diffuse scattering.

Based on our results, we plan to expand our investigations on other complex intermetallic compounds.