Interfacial structure in (111) Au:Ni multilayers investigated by anomalous x-ray diffraction

We have investigated the structure of buried interfaces in (111) Au:Ni multilayers. Conventional x-ray diffraction at constant energy as well as anomalous x-ray scattering across the Ni absorption K edge have been used. Whereas the fitting of the spectra at a single energy leads to two different possible interfacial structures, the anomalous diffracted intensity variation unambiguously favors a model with an interfacial concentration gradient at one interface. The multilayer presents an intermixed region extending on six atomic planes around the Ni/Au interface, whereas the Au/Ni interface is chemically abrupt. This structure can explain the unusual stress-strain relation previously reported on this system.