Strong vortex pinning by elongated, discontinuous defects in Tl-Ba-Ca-Cu-Ofilms

Elongated, discontinuous defects provide strong vortex pinning and a corres ponding large increase in critical current density in highly anisotropic Tl 2Ba2CaCu2Ox (Tl-2212) thin films. We generate controlled, amorphous damage regions in Tl-2212 thin films ranging from short, discontinuous defects to continuous linear tracks using Au ion irradiation with incident energies of 30, 60 and 88 MeV. High-resolution TEM images and magnetization data allow correlation of microstructural damage with changes in the superconducting properties. Furnace annealing of an irradiated film shows that the enhanced pinning is stable to above 600 degrees C.