STRONGLY ENHANCED VORTEX PINNING IN HIGH-ENERGY, HEAVY-ION-IRRADIATED, SUPERCONDUCTING TL-BA-CA-CU-O FILMS

Lattice damage introduced in high-temperature superconducting Tl2Ba2Ca Cu2Oy thin films by irradiation with 60 MeV Cu9+ ions produces a large enhancement in both the critical current density J(cm) and the vortex volume pinning force. These promising effects are observed for a flue nce of 2 x 10(11) ions/cm(2) that causes a small decrease (similar to 4%) in the superconducting transition temperature. At 40 K in a one Te sla magnetic field applied along the crystallographic c-axis, at dissi pation levels dictated by the SQUID magnetometer, J(cm) is increased b y orders of magnitude following irradiation. High-resolution transmiss ion electron microscopy reveals extended, linear defects following irr adiation that provide strong vortex pinning sites, allowing much highe r J(cm).