Experimental study on giant vortex and multivortex states in mesoscopic superconductors

Two experimental methods for distinguishing between giant vortex and multivortex states in mesoscopic superconductors are described: the multiple-small-tunnel-junction method and the temperature dependence of vortex expulsion fields. The former provides a direct evidence for the existence of the giant vortex state in disks, while the latter might be applicable to mesoscopic superconductors with various shapes such as squares and triangles. The experimental results are well reproduced in numerical results based on the nonlinear Ginzburg–Landau theory.