(a) Simulated intensity and (b) the corresponding electron-density profiles for a 3.5 nm-thick LSCF film on NGO at 973 K. The circles in (a) indicate the L0 positions where RAXR spectra were computed (Fig. 5). Model A: constant strontium distribution. Model B: strontium segregations towards the interface and surface, leading to a larger electron density in the center because of a larger amount of lanthanum. Model C: strontium segregation in the center of the film. The electron-density profile of NGO(110) is situated below zero (z = 0 at the NGO bulk surface). Note that no interfacial region is simulated. The AO-plane electron-density peaks are connected by a dashed line to visualize the effect of strontium segregation (low-density regions). Curves are offset for clarity.