Supercurrent distribution in high-T-C superconducting YBa2Cu3O7-y thin films by scanning superconducting quantum interference device microscopy

The two-dimensional vector mapping of current distributions in high-T-C sup erconducting YBa2Cu3O7-y thin films obtained by converting magnetic-field d ata measured by scanning superconducting quantum interference device (SQUID ) microscopy is reported. The current distribution contains the contributio ns from both transport supercurrent and vortex current. The transport super current is found to flow mainly along the edge of a stripline, and the nume rical calculation based on the simple London model by taking the specific s ample-detector geometry into account is given. The agreement between the ex perimental data and the calculated results is good, demonstrating that the scanning SQUID microscope provides a useful tool for studying the current d istribution in a superconductor. (C) 2000 American Institute of Physics. [S 0003-6951(00)03145-4].