Size dependence of the vortex states in mesoscopic superconductors

We investigated the sample size dependence of the types of vortex states, i.e., multivortex states or giant vortex states, in mesoscopic superconducting squares by using the temperature dependence of vortex expulsion fields. The giant vortex states are stable in small samples and at high magnetic fields. The experimental results are compared with theoretical simulations based on the nonlinear Ginzburg-Landau theory.