Laser deposition of YBaCuO thin films: stress measurements and microstructure investigations

Superconducting thin films of YBaCuO have been deposited by laser ablation at 7508C on MgO 001.single crystals. X-ray pole figures indicate a high crystalline quality of c-axis oriented films. A four-circle X-ray goniometer has been used for the measurements of the internal stress in the films by means of the fundamental metric tensor method generally used in the field of continuum mechanics. Microstructural investigation has been done by HRTEM on plan-view samples in order to study the film–substrate epitaxy relations from the observation of the moire´ pattern brought about by the superimposition of both YBaCuO and MgO lattices 9% misfit.. The results are discussed in terms of crystallographic accommodation and stress relaxation between the film and the substrate. q1999 Elsevier Science B.V. All rights reserved