Supercurrent unbalance due to in-plane asymmetry of defected regions with respect to the sample geometry

A modulation of the supercurrent distribution in superconductors results in a long-range disturbance due to the strong nonlinearity of the constitutive relation between electric field and current density in the superconducting state. Here we present the relevant cases of local modulations of the superconducting properties in thin specimens, with asymmetric positioning of the modulated region with respect to the sample geometry, but retaining the same shape of the sample itself. The local modulation, that induces the long-range disturbance of the superconducting condensate, is produced, in our case, either by a vanishing order parameter, a void, or by nanostructured defects, with finite values of the order parameter. In the latter case, local structural modulation on the nanometric scale were produced in microscopic areas by confined high-energy irradiation with heavy ions. The quantitative magneto-optical analysis directly reveals the local supercurrent distribution and thus the features of the long-range disturbance. A novel phenomenology in presence of these asymmetric supercurrent modulations is observed, such as supercurrent unbalance effects (in dependence on the incidence angle of the current density, with respect to the defect interface, and on the external magnetic field), and a pattern transition in the vortex state of the modulated region.