Effect of sputtering gas on the surface composition of an Al-Pd-Mn quasicrystal

We demonstrate the effects of different inert sputtering gases on the surfa ce composition of icosahedral (i-) Al-Pd-Mn. The sputtering gases used incl ude He, Ne, Ar, Xe, and Kr. We demonstrate that the steady-state compositio n is independent of the inert gas chosen. This steady-state composition fal ls outside of the quasicrystalline region of the Al-Pd-Mn phase diagram. Ho wever, the fluence (ions/cm(2)) to achieve steady-state depends on the iner t gas. Helium requires a much higher fluence than the other gases. Because of this, He can be used to clean the surface, if the time (fluence) for spu ttering is kept to a minimum, without causing the large compositional shift induced with a relatively small fluence by the most common sputtering gas, Ar. (C) 2000 Elsevier Science B.V. All rights reserved.