Investigation of ‘‘connectivity’’ in silver-ceramic superconductor composites by their field screening property

In this paper we outline an experimental method and a theoretical framework by which the strength of weak superconducting links in granular ceramic systems is compared and measured. This new method is based on dc measurement of screening properties of superconducting materials and renders a simultaneous determination of the critical magnetic field and the penetration length. In particular, the method is applied to a series of newly developed nonrandom silver-YBa2Cu3O7−δ composites. By measuring the field screening property in these materials, the effectiveness of various sintering processes can be judged.