Vortex pinning and rectification effect in a nanostructured superconducting film with a square array of antidot triplets

摘要

We study the stability of vortices pinning and dynamics in a superconducting thin strip containing a square array of antidot triplets by using the nonlinear Ginzburg-Landau (GL) theory.Compared with the regular square array of circular holes,the vortices are no longer pinned inside the circular holes,but instead stabilized at the center of the antidot triplets depending on the geometry parameters.Moreover,the influences of the geometry parameters and the polarity of the applied current on the current-voltage (I-V) characteristics are also studied.The critical current for the sample turning into a normal state becomes smaller when the hole diameter D is smaller and the spacing B between the holes is larger.Due to the asymmetric pinning sites,our numerical simulations demonstrate that the positive and negative rectified voltages appear alternately in the resistive state of the sample under an ac current of square pulses.