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

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