Strongly Enhanced Vortex Pinning In High-Energy, Heavy-Ion-Irradiated, Superconducting Tl-Ba-Ca-Cu-O Films

Lattice damage introduced in high-temperature superconducting Tl2Ba2CaCu2Oy 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 fluence 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 Tesla magnetic field applied along the crystallographic c-axis, at dissipation levels dictated by the SQUID magnetometer, J(cm) is increased by orders of magnitude following irradiation. High-resolution transmission electron microscopy reveals extended, linear defects following irradiation that provide strong vortex pinning sites, allowing much higher J(cm).