Enhanced Flux Pinning in YBa2Cu3O7–delta Films by Nanoscaled Substrate Surface Roughness

by Zu-Xin Ye et al. Applied Physics Letters, 19 Sep 2005 Nanoscaled substrate surface roughness is shown to strongly influence the critical current density (J_c) in YBa₂Cu₃O_7– (YBCO) films made by pulsed-laser deposition on the crystalline LaAlO₃ substrates consisting of two separate twin-free and twin-rich regions. The nanoscaled corrugated substrate surface was created in the twin-rich region during the deposition process. Using magneto-optical imaging techniques coupled with optical and atomic force microscopy, we observed an enhanced flux pinning in the YBCO films in the twin-rich region, resulting in a ~30% increase in J_c, which was unambiguously confirmed by the direct transport measurement. Read more