Variability residual stresses of thick superconductor films during orthorhombic to tetragonal transformation

摘要

YBa(sub 2)Cu(sub 3)O(sub x) thick films have been deposited by spray pyrolysis of a sol-gel on 10 cm diameter polycrystalline MgO wafers. The film thickness was built up in layers of approximately 1 (mu)m thick. The in-plane residual stresses were measured by an optical interferometry (shadow moire) method as a function of film structure. In-plane residual stress maps over the area of the wafer have been obtained. The average stress of the 5 (mu)m orthorhombic phase was 0.84 GPa. As the film transforms from the orthorhombic to the tetragonal structure, the tensile stresses decreased by 0.5 GPa.