Direct observation of stronger flux-line pinning of crossed compared to parallel linear defects

Linear defects were introduced in high-temperature superconductors (HTSC’s) by high-energy heavy-ion irradiation. Flux penetration into partly crossed and parallel irradiated HTSC’s was observed by magneto- optics. The obtained flux distributions show that the critical current density ${\mathit{j}}_{\mathit{c}}$ in cross-irradiated HTSC’s is larger by a factor up to 14 than in parallel irradiated HTSC’s. © 1996 The American Physical Society.