Effect of current and voltage leads on the superconducting properties of mesoscopic triangles

The superconducting/normal phase boundary of mesoscopic triangles is studied by transport measurements. The presence of voltage and current leads, intrinsic to transport measurements, may produce pronounced resistance peaks close to the normal/superconducting transition. These phenomena are explained by taking into account the presence of charge imbalance around superconducting/normal interfaces. The resistance peaks in the vicinity of Tc can be suppressed by choosing the right shape for the current and voltage contacts. The measured critical temperature Tc(H) is compared with recent theoretical curve obtained in the framework of the linearized Ginzburg–Landau theory. A good agreement between the theory and our experiments is found.