Interface modification by swift heavy ions

The modification of thin layer interfaces by ion irradiation (ion beam mixing) is the most elegant way to learn about the atomic transport processes induced by the energy deposited along the ions path. Ion beam mixing in the nuclear stopping regime has been intensively studied for about 30 years, while ion beam mixing by electronic energy deposition became a matter of interest only after about 1993. In this paper an attempt will be made to briefly summarise the present knowledge on atomic transport processes induced by the electronic energy loss of swift heavy ions on the basis of our recent ion beam mixing experiments with layered systems. Swift heavy ion beam mixing is strongly related to nuclear track formation and therefore a short introduction into the present ideas of the ion's energy deposition and the track formation processes will be given. Afterwards the few experiments on high-energy ion beam mixing performed until recently will be shortly reviewed. Finally we will discuss in detail our mixing data in ceramic systems and show that swift heavy ion beam mixing is a threshold process and results from transient interdiffusion in the molten ion track. (C) 2003 Elsevier Ltd. All rights reserved.