Resonant X-ray scattering studies of epitaxial complex oxide thin films

Resonant anomalous X-ray reflectivity (RAXR) is a powerful technique for measuring element-specific distribution profiles across surfaces and buried interfaces. Here, the RAXR technique is applied to characterize a complex oxide heterostructure, La0.6Sr0.4Co0.2Fe0.8O3-delta, on NdGaO3, and the effects of data sampling and model-dependent fitting procedures on the extracted elemental distribution profile are evaluated. The strontium profile through a 3.5 nm-thick film at 973 K and at an oxygen partial pressure of 150 Torr (1 Torr = 133.32 Pa) was determined from the measured RAXR spectra. The results demonstrate that in situ RAXR measurements can provide key insights into temperature-and environment-dependent elemental segregation processes, relevant, for example, in assessing the cathode performance of solid oxide fuel cells.