Changing the Critical Current Density and Magnetic Properties of YBa $_2$Cu$_3$ O$_7$ by Using Large Antidots

The current-carrying ability of type II superconductors can be effectively enhanced by introducing certain intelligent defects within the material. These defects can also give rise to other practically and scientifically appealing effects, such as current rectification, flux quantum filtering, and inhomogeneous response to external magnetic field and applied current. One such intelligent defect, which can be artificially fabricated in a controlled manner, is the removal of the superconductor in periodic regions throughout the sample, known as an antidot. In this paper, large-scale antidots of the order of 2-3 μm were used in different shapes to discover potentially novel effects due to differing pinning potentials. Different shapes had varying responses to the critical current, some of which enhanced the flux pinning capacity. Large-scale antidots were also used to create a ratchet effect by utilizing the orientation of triangles in two different samples to pin vortices in unbalanced fashion depending on applied current/magnetic field direction.