Transport properties and flux pinning by self-organization in YBa₂Cu₃O_7-δ films on vicinal SrTiO₃(001)

We have observed anisotropic flux pinning and resistivity in the substrate plane of YBa₂Cu₃O_7-δ (YBCO) thin films grown on vicinal SrTiO₃(001) with the c axis oriented along the SrTiO₃ [001] direction. Using UHV scanning tunneling microscopy and transmission electron microscopy we demonstrate the influence of a periodic nanoscale step structure of the clean substrate surface on the morphology and defect microstructure of subsequently deposited YBCO films. A linear array of dislocations generated via self-organization of the YBCO leads to an exceptionally large critical current density up to 8×10¹¹A/m² at 4.2 K. The findings indicate that the critical current density of high-temperature superconductors can be enhanced in a controlled way growing thin films on tailored substrate surfaces.