Evidence for weak-link and strong-link couplings in high Tc granular superconductors, detected from the geometric influence on Jc-H behavior

The Jc vs H characteristics of several samples were studied in connection with their geometry. The onset decoupling field was compared and correlated with a characteristic field of the weak‐link array already introduced in a previously developed model. It is concluded that this characteristic field coincides with the decoupling field H0 defined by the junction area, not dependent on the geometry but on the microstructure of the sample. The role of weak‐link and strong‐link junctions in the critical current density was established from the dependence of the Jc vs H curves on geometry.