Two-dimensional vortex-pinning phenomena in y Ba2 Cu3 Oy films

Anomalous superconducting properties were demonstrated in anisotropic high-critical-temperature superconductors (HTSCs) by simultaneously introducing two different planar types of vortex-pinning centers. The nanostructure, magnetic field, and field-angle dependency of critical current properties for an a -axis-grown multilayered film consisting of superconducting and semiconducting layers were characterized. Semiconductive layers running perpendicular to Cu O2 superconducting layers behave as novel two-dimensional vortex-pinning centers that reverse the typical magnetic response in the superconducting state observed for conventional HTSCs. The results indicate that the vortex behavior in nanostructured HTSCs can be controlled; therefore, significant potential exists for further improvement of the critical current properties.