Figure 4

MEIS data in random mode.

Incident particles : 100 keV He⁺ ions. (a,b) MEIS random maps (E₁, θ_sc, N) of the samples with a film thicknesses of (a) 3 u.c. (b) 5 u.c. Top (-bottom) layers of highest (-lowest) energies correspond to He⁺ particles backscattered on La (-Sr) respectively. Red lines locate the position (at a fixed scattering angle) of the profiles extracted. (c,d) Random MEIS experimental and simulated spectra of the (c) 3 u.c. sample with a backscattering angle of 115,4° (d) 5 u.c. sample with a backscattering angle of 114,5°. The blue curves simulate MEIS theoretical spectra for non-intermixed and fully stoichiometric LAO/STO heterostructures. Experimental spectra are plotted with red dots, whereas the best simulated hetero-structures are represented by a green curve. (e) La/(La+Sr) profile throughout the first atomic layers. The x coordinates locate the cations by the number of unit cells to the interface (+1 = first u.c. in STO, −1 = first u.c. in ). The film contains a cumulative amount of 0.9 +/− 0.05 Sr in the 5 u.c. sample (thus 4.1 +/− 0.05 La) and 0.5 +/− 0.05 Sr in the 3 u.c. one (thus 2.5 +/− 0.05 La). The La counter-diffusion depths were similar for the two samples, with 0.8 La for 5 u.c. and 0.7 La for 3 u.c. films.