Abstract

The Josephson effects [1] are very important to many areas of modern superconductivity research. Their most obvious and direct relevance is to the study and development of active superconducting electronic devices. Here, Josephson junctions form the basic elements of superconducting quantum interference devices (SQUIDs) [2], single flux quantum (SFQ) logic [3], junction arrays for the voltage standard [4] and for high-frequency radiation sources [5]. However, for most high-temperature superconductors (HTS), they govern the transport of supercurrent in a significant number of situations. For example, a number of HTS materials appear to be Josephson coupled perpendicular to the copper oxide planes [6]. In addition, the Josephson effect often limits the flow of current in poorly aligned polycrystalline material [7].