RBS and ion channelling study of YBCO/STO and YBCO/LSMO/STO structures. Oxygen content estimated by X-ray diffraction

The structure and the elemental depth distributions of Y1Ba2Cu3O7-d (YBCO) and La0.7Sr0.3MnO3 (LSMO) were examined by q-2q XRD, and by 1.7 MeV 4He+ Rutherford Backscattering Spectrometry (RBS) in random and channeling geometry. The YBCO layers were magnetron sputtered, where the only one varying parameters were the oxygen pressure and the annealing time. The layers have high crystalline qualitiy and an almost sharp interface with the substrate as revealed by the analysis. It is shown that the oxygen content influences considerably not only the superconducting behavior, but also the lattice parameters and the cmin parameter (the minimum yield which is the ratio of aligned to random Rutherford backscattering spectra). We have found by high-precision RBS simulation, that independent on the film quality, a disordered interface region of 20 to 30 nm is present in all structures. As a complementary study we have performed also AES depth profiling.