Molecular dynamics simulations of non-equilibrium systems

Peer reviewe

Atomic mixing of Ni2O3 SiO2, NiO SiO2, and Ni SiO2 interfaces induced by swift heavy ion irradiation

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 S e 28 keV nm and does not exhibit mixing with its SiO2 substrate. In addition, NiO SiO2 and Ni SiO2 were irradiated in the nuclear stopping regime with 600 keV Kr and 900 keV Xe ions. Here the intermixing effect is in good agreement with the assumption of ballistic atomic transpor