RESONANT X-RAY REFLECTIVITY STUDY OF FE CR SUPERLATTICES/

We have measured the composition profile on an Fe/Cr superlattice usin g glancing incidence X-ray reflectivity. Resonant reflectivity measure ments were carried out by tuning the X-ray energy around the respectiv e K-edge of Fe and Cr. We were able to obtain excellent fits to the da ta and get consistent geometry and composition parameters from the ref lectivity measurements at six different X-ray energies. We obtained va luable information on the interface composition of the superlattice an d observed also a slight variation in composition at the bottom and to p interfaces. The information obtained using this method allows a dete rmination of not only the electron density but also the composition pr ofiles of the multilayers. This non-destructive technique is a promisi ng tool for the determination of the chemical composition of thin film .