Ion Channeling in Quasicrystals

Summary

It is the aim of this chapter to outline the principles of ion chapter in quasicrystals and to give an overview of the potential applications of this technique. We will see that in quasicrystals there exist rows and planes of atoms which are the prerequisite for channeling in ordered structures. In contrast to periodic lattices in quasicrystals these rows and planes exhibit a wide distribution of densities. This causes problems, in part, but does not render channeling impossible.

While the first ion channeling investigations in quasicrystals were almost exclusively concerned with proving its existence, it was subsequently found that ion channeling is particularly useful for the investigation of the decoration of the quasicrystalline lattice by the different atom species present in these materials. Examples are shown for d-AlCuCoSi and i-AlPdMn. According to this work there still exist considerable discrepancies between the results of these experiments and of channeling calculations performed for the presently available structure models. The discrepancies are particularly strong for i-AlPdMn and indicate that Boudard’s model and related models still require major changes. Suggestions for solving this problem are given.

In the final section it is shown how ion channeling may be used to determine the interstitial positions of small amounts of impurities in quasicrystals. It is a powerful technique and has been frequently used in the case of periodic crystals.