The role of individual defects on the magnetic screening of HTSC films

The magnetic flux penetration into thin films of high-temperature superconducting YBCO is visualized with high spatial resolution via x-ray microscopy. Therefore superconductors are coated with soft-magnetic CoFeB layers that reproduce the magnetic flux density distribution in an adjacent superconducting film and exhibit at the same time a large XMCD effect. For the first time we present scanning x-ray microscopy in the total electron yield mode using polarized x-rays providing simultaneously structural and magnetic information of the surface with high spatial resolution. Correlating the images of structural and magnetic information the role of individual defects on the magnetic screening capability of the superconductor can be identified.