Principal Investigator: Andreas Glatz, Ph.D., Department of Physics.
In this project, we study the pinning behavior of thin superconducting films or strips. When applying a magnetic field to a superconductor it can enter in the form of discrete vortices that dissipate energy when they start moving under an applied electric current due to the Lorentz force. However, defects in the superconductor material can offset this effect by 'pinning' vortices, preventing their motion.
In superconducting films, artificial pinning arrays of localized defects can be nanofabricated and represent therefore an ideal testbed to study different mechanisms of pinning, while at the same time being technologically very important systems. Another way of restricting the motion of vortices is by changing the geometry of the sample to, e.g., narrow strips.
Here we study both, nano-patterned films and strips, using large-scale time-dependent Ginzburg-Landau numerical simulations running on GPUs. These simulations allowed to predict optimal pinning arrays for largest critical current or describe a way to use magnetoresistance measurements to analyze the vortex structure in narrow strips. Many simulations were done on Gaea at NIU. Others at ALCF at Argonne National Laboratory.