Anisotropic strain in YBa₂Cu₃O_7−δ films analysed by deconvolution of two-dimensional intensity data

The influence of the instrumental resolution on two-dimensional reflection profiles of epitaxic YBa₂Cu₃O_7−δ films on SrTiO₃ (001) has been studied in order to investigate the strain in the superconducting films. The X-ray diffraction intensity data were obtained by two-dimensional scans in reciprocal space (q-scan). Since the reflection broadening caused by the apparatus differs for each position in reciprocal space, a highly crystalline substrate was used as a standard. Thus it was possible to measure a standard very close to the YBa₂Cu₃O_7−δ reflections in reciprocal space. The two-dimensional deconvolution of reflections by a new computer program revealed an anisotropic strain of the two twinning systems of the film.