Standing-wave-assisted extended x-ray absorption fine-structure study of a Ni-Ti multilayer

Abstract
Extended x-ray absorption fine structure (EXAFS) measurements have been made while simultaneously exciting x-ray standing waves in a multilayer structure. This allows the EXAFS signal from selected regions within the multilayer unit cell to be enhanced. The technique is applied to a Ni-Ti multilayer in which it is verified that strong standing-wave fields can be excited in the presence of substantial interfacial roughness. The measurements reveal little Ni-Ti intermixing and a strong low-Z impurity signal in the Ti layers. The standing-wave analysis indicates that the low-Z impurity is distributed throughout the Ti layers.