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

Superconducting thin films of YBaCuO have been deposited by laser ablation at 750 degrees C on MgO (001) single crystals. X-ray pole figures indicate a high crystalline quality of c-axis oriented films. A four-circle X-ray go niometer has been used for the measurements of the internal stress in the f ilms 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 su perimposition 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. (C) 1999 Elsevier Science B.V. All righ ts reserved.