Mapping the current distribution in YBa2Cu3O7−x thin films with striations

We have studied the transport current distributions in striated YBa2Cu3O7−x (YBCO) films and coated conductors using variable temperature scanning laser microscopy (VTSLM). VTSLM images reveal the location of incomplete separation between filaments due to un-optimized sample processing parameters. When the current flows parallel to the completely separated striations, the current seems to flow within a strip without inter-mixing via the substrate. Initial resistivity measurements on metallic inter-filamentary connections (gold dots) exhibit a semiconducting behavior. VTSLM images clearly show that the current flows between filaments via the metallic inter-connect, indicating the semiconducting resistive behavior is due to the interface between YBCO and metallic layer. The results demonstrate the potential of VTSLM technique in investigating current sharing and normal metal inter-connect issues for the coated conductor development for ac applications.