Atomic mixing of Ni 2 O 3 /SiO 2 , NiO/SiO 2 , and Ni/SiO 2 interfaces induced by swift heavy ion irradiation

Abstract

We have investigated the interface mixing of Ni2O3/SiO2, NiO/SiO2, and Ni/SiO2 induced by the irradiation with Ar, Kr and Xe ions of energies ranging from 90 MeV to 260 MeV. Since these energies are in the electronic stopping regime, atomic transport processes will not be directly initiated by elastic ion–target collisions, but need to be excited by secondary processes like electron–phonon coupling or Coulomb explosion. Nevertheless, we have observed a strong mixing effect in the ceramic systems if the electronic energy loss exceeds a certain threshold value. Estimation of an effective diffusion constant indicates that diffusion takes place in the molten ion track. In contrast to the ceramics, the metallic Ni layer is still insensitive even for the highest electronic stopping power used (Se=28 keV/nm) and does not exhibit mixing with its SiO2 substrate.