Vortex Dynamics in Confined Systems Studied by Scanning

We report on a study of vortex arrangements in mesoscopic superconductors using scanning tunneling microscopy and spectroscopy. Using NbSe$_{2}$ single crystals and conventional ion beam lithography we defined different mesoscopic systems that confine vortex motion. The spatial confinement of vortices introduces novel collective behavior that strongly depends on the size of the superconductor, vortex density, and temperature. We will compare the experimental results with existing theoretical models based on Ginzburg-Landau theory.