Investigation of defects in functional layer of high temperature superconducting tapes

(RE)BCO-based superconducting tapes were studied to clarify the correlation between structure of the (RE)BCO layer and the critical current density. For this purpose, both etched and cross-sectioned samples of (RE)BCO tapes were investigated by means of SEM and EBSD techniques. The outgrowths penetrating deeply into the (RE)BCO layer were found. Their non-uniform distribution density profile across a tape width was closely related to the profile of critical current density. Grains in (RE)BCO outgrowth-free regions, outgrowths themselves and neighboring regions of outgrowths were found to differ from each other in crystal orientation. It was shown that the presence of outgrowths may cause localized changes in crystal orientation of superconducting layer and in this way it may affect the critical current density.