Anisotropic vortex pinning in superconductors with a square array of rectangular submicron holes
L. Van Look, B. Y. Zhu, R. Jonckheere, B. R. Zhao, Z. X. Zhao, V. V. Moshchalkov
Abstract
We investigate vortex pinning in thin superconducting films with a square array of rectangular submicron holes ("antidots"). Two types of antidots are considered: antidots fully perforating the superconducting film, and "blind antidots", holes that perforate the film only up to a certain depth. In both systems, we observe a distinct anisotropy in the pinning properties, reflected in the critical current Ic, depending on the direction of the applied electrical current: parallel to the long side of the antidots or perpendicular to it. Although the mechanism responsible for the effect is very different in the two systems, they both show a higher critical current and a sharper IV-transition when the current is applied along the long side of the rectangular antidots.