Probing slow diffusion by nuclear reflectivity of synchrotron radiation

Full text: Up to now, the radio-tracer technique has been used to study mesoscopic and macroscopic diffusion dynamics. The resolution of diffusion depths is limited by the detector efficiencies and sputtering resolving power. On the other hand scattering methods with atomic resolution like QMS, NRS and QNS have very limited range of accessible diffusion coefficients. We used a new method for grazing incidence nuclear resonant scattering of synchrotron radiation for investigations of iron self-diffusion in L10-FePt thin films and B2-FeSi metastable films. The method is highly sensitive. The Investigations are non-destructive and non-contaminating. It is possible to measure very low rates of diffusion of about 10-23m2s-1 to 10-25m2s-1. (author)