Defect-modulated Long Josephson Junctions as source of strong pinning in superconducting films

A model based on long Josephson junction (LJJ) modulated by columnar defects shows that the modulated depth of Josephson potential wells, the length scale of disorder, and the defect density, as well as the variance of their sizes are responsible of the plateau-like features in critical current density vs field logarithmic curves. The fitting of the defect structure to the “matching” fields is also discussed. The ordered structure represented by a LJJ with “stripes” alternately penetrated by a quantum flux and not penetrated, is the reference feature for controlled disorder in LJJ. This feature drives the best accommodation of the matching fields in a given detect lattice.