Interface flux pinning in i n s i t u formed superconducting composites

Detailed flux flow studies of in situ formed wire and tape superconducting composites confirm our earlier findings that the filament-matrix interfaces are effective flux pinning centers. Angular dependence measurements on tape composites, where the ribbon-like filaments are parallel to the rolling plane, reveal a critical current anisotropy which depends on the magnetic field. The flux pinning force is also anisotropic; its complex field dependence, however, cannot be fully described using the existing flux pinning theories.