DOUBLE STEP BEHAVIOR OF THE CRITICAL CURRENT VERSUS MAGNETIC FIELD IN A BULK JOSEPHSON MEDIUM

This paper discusses the physics of the influence of a strong magnetic field H on the high T c metal ceramic critical current J c . The problem of boundary conditions for a surface current value in hard superconductors is analyzed. It is shown that if Abrikosov vortices in granules are rigidly pinned, the J c vs H dependence has a plateau region of relatively constant critical current. The hysteresis of ceramic critical current is calculated on the basis of the Josephson weak link model.