Critical Current Problems in Neutrons Irradiated HTc Multilayered Superconductors

In the paper there is given an analysis of the critical current problems in irradiated multilayered high temperature oxide superconductors. Critical current for the direction of current flow inside the layers is investigated basing on analysis of the capturing interaction of pancake vortices with nanodefects, created by fast neutrons irradiation. Analysis of the pinning potential barrier formation is presented. From performed calculations of current-voltage characteristics fitted to measurements the inherent pinning centers concentration and their average dimensions were estimated. The case of perpendicular to layers current has been regarded too, taking into account the intrinsic Josephson junctions formation. The influence of nanodefects concentration on the Josephson penetration depth has been considered, whose length determines the Swihart velocity and current-voltage characteristics of junction.