Enhanced critical current densities in (Bi,Pb)/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 2/O/sub 10/ silver-sheathed tapes by splayed columnar defects after 600 MeV proton irradiation
Splayed columnar defects are efficient pinning centers for magnetic vortices in high-T/sub c/ superconductors. Irradiation with 600 MeV protons as primary projectiles generates heavy fission fragments in (Bi, Pb)/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 3/O/sub 10/ via a p-Bi nuclear reaction. The high-Z secondary projectiles are sufficiently energetic to create randomly oriented columnar defects with important effects on the magnetic and transport critical current densities of (Bi,Pb)/sub 2/Sr/sub 2/Ca/sub 2/Cu/sub 3/O/sub 10/ Ag-sheathed tapes. These effects are discussed on the basis of the splayed defect topology.