The evolution of the Ni/Al(111) interface was studied in situ by means of X-ray absorption spectroscopy at the Ni-K edge. Films of Ni were deposited onto bulk Al(111) to thicknesses ranging from 2 to 30 monolayers. The object was to determine the diffusion length of Ni. The Ni diffused spontaneously, at room temperature, to a depth that was estimated to be of the order of 11 monolayers. The structure of the Ni/Al(111) mixed interface was characterized by using X-ray absorption spectroscopy. The first phase formed on Al(111) was Al3Ni2-like, instead of AlNi-like. Accordingly to previous observations, an AlNi3 phase formed on top of Al3Ni2 after deposition of the first few monolayers. It was proposed that the pure Ni growth, observed after deposition of 11 monolayers, was due to the presence of AlNi3; which acted as a diffusion barrier that prevented deeper Ni penetration into the Al at room temperature.

Structural Characterization of Ni/Al (111) Interface by Surface X-Ray Absorption Spectroscopy. L.Damoc, E.Fonda, P.Le Fevre, A.Traverse: Journal of Applied Physics, 2002, 92[4], 1862-7