Ni atomic environment in epitaxial NiO layers on Ag(001)

This paper reports a structural study of 3 and 10 ML thick NiO films grown on Ag(0 0 1). Polarization-dependent Xray absorption spectroscopy at the Ni K-edge allowed us to obtain an accurate description of the local atomic environment of the Ni atoms, including the determination of the in-plane and out-of-plane strains for the NiO films. Multi-shell multiple scattering calculations have been used to fit the data. The local structure of Ni is always very similar to that of bulk NiO, with no detectable interdiffusion of Ag from the substrate. A compressive in-plane epitaxial strain has been found at 3 and 10 ML, indicating that the relaxation is not complete at 10 ML. (C) 2002 Elsevier Science B.V. All rights reserved.