Correlated Disorder in YBCO and Composite YBCO Films Revealed by Means of Synchrotron X-Ray Diffraction

The presence of lattice correlated disorder in real materials places further demands on the understanding of the structure-function relationship. The study of this disorder is quite challenging, since it can be due to various and interconnected reasons. This requires advanced probes able to measure weak structural features. Thanks to synchrotron radiation features, nowadays, it is possible to visualize structural disorder alongside its spatial distribution and time dynamics. In this context, we aim to characterize thin-film superconducting YBa₂Cu₃O_7-x, whose structure is particularly rich. Indeed, here, the nanogranularity related to superlattices, distribution of dopants, and strain-induced stoichiometry inhomogeneity are coupled with the intrinsic granularity arising from the material island growth mode, which leads to small grains (~200 nm) and a large network of grain boundaries. X-ray Grazing incidence diffraction has been used to visualize low-dimensional lattice disorder in optimally doped YBa₂Cu₃O_7-x with inclusion of BaZrO₃ nanodefects grown on SrTiO₃ single crystals. The results are expected to shade light on interplay of lattice disorder and the electronic quantum coherence in the superconducting state.