Stacked Josephson Junctions

Abstract

The topic of fluxons in Josephson junctions appears often and in many contexts within superconductivity. The potential applications and the appearance of high-T _c superconductivity are some of the reasons for this recently increased interest. Several comprehensive reviews of fluxons (solitons) in long Josephson junctions [8], [2], [10], [9] exist, of which particularly the most recent [9] gives an excellent overview of the state of the art for low- T _c niobium-type long Josephson junctions. In recent years the properties of long Josephson junctions stacked on top of each other has been studied quite intensively. This is because such systems model existing low-T _c superconducting multilayers. In addition these models have revealed surprising dynamical properties. The appearance of high-T _c ceramic superconductors has also had quite an impact on the topic of fluxons in superconductors, in particular stacked long Josephson junctions. Here the fluxons play a very important role, for example, in the BSCCO type of material with a layered structure and big anisotropy. Dynamic properties of fluxons are also relevant for the material properties such as the bulk current density and the behaviour near the transition temperature. Some of these high-T _c phenomena we will try to include in our description below.