Atomic mixing induced in metallic bilayers by high electronic excitations

It has been recently established that high levels of energy deposition in electronic excitations can induce damage creation in a few metallic targets as soon as the linear rate of energy deposition in electronic excitation is of the order of a few 10 keV/nm. The present study is aimed at determining whether high electronic excitations can induce interdiffusion at the interface of metallic bilayers. Ni Ti bilayers were irradiated at 80 K with GeV Ta ions up to a few 10¹³ ions/cm². Damage creation and mixing were followed using various methods: X-ray and neutron reflectometry, X-ray diffraction, electron microscopy and electron energy loss on transverse cuts. A very strong mixing is observed at the Ni Ti interface as a result of high electronic excitations.