Intergranular critical state in uniform Josephson junction arrays

Abstract

Static intergranular magnetization curves of uniform slab-like Josephson junction arrays with a large junction-critical-current, I max, and/or a large void area, A V, are calculated as the fully relaxed solutions of a set of DC and AC Josephson equations with gauge-invariant phase differences. The curves always have an oscillatory component. When μ 0 A V I max/ φ 0 > 0.5, they are very similar to those calculated from the critical-state model of constant J c. In this case, there are many possible static states under each given field, the intergranular critical state is the most effective static shielding state with a regional feature selected by dynamic shielding during previous field change. The implications of the results for the mechanism of the intergranular critical state in high- T c superconductors are discussed.