Search

A comparative study of the Fiske steps and zero-field steps of Josephson tunnel junctions having lateral and longitudinal idle regions and those of naked tunnels helps assess the influence of these idle regions, which are insulating regions, on electromagnetic wave phase velocity. An idle region, which occurs parallel to the perimeter of the junction and does not carry any dc current, is a superconductor-insulator-superconductor structure. The lateral idle region in long junctions enhance the phase velocity of the electromagnetic waves and the fluxon rest mass, while the longitudinal idle region reduces phase velocity.

We experimentally demonstrate that in the presence of an in-plane magnetic field the voltage-current curve of a Nb thin strip having plano-convex cross section exhibits considerable asymmetry of the critical current. The observed behavior can be accounted for by the magnetic field component normal to the top convex surface of the strip. Such a component is inhomogeneous, changes sign in the middle of the strip and affects the three-dimensional vortices that in this system have sections locally perpendicular to the top convex surface, though the magnetic field is applied parallel to the bottom flat surface. These sections play the most significant role in the generation of the observed asymmetry. A maximum asymmetry ratio of about 300% at 4.2 K is observed when the strip is in the mixed state and can be ascribed to the balance of the magnetic force due to the inhomogeneous field component and the polarity dependent Lorentz force associated to the transport current. [ABSTRACT FROM AUTHOR]

Presents a study which reported the behavior of the rf-induced steps in unidimensional Josephson-tunnel junctions. Equation for the dynamics of a unidimensional Josephson junction having overlap geometry; Procedure for testing niobium-niobium, oxygen and lead junctions; Results of the study.

Presents a study that tested a device based on a series array of highly hysteric Josephson junctions coupled to a microstrip resonator. Possibility of connecting more junctions in series to get a higher Josephson voltage; Difficulty of optimizing the junction areas to get higher critical currents; Problems encountered in the experiment.