Temporal Behavior of the Breakdown of Superconductivity

Abstract

On a very short time scale, breakdown of superconductivity with increasing transport current turns out to be a highly dynamical process, called “current-induced resistive state”. Magnetic flux domains rapidly move perpendicular to the direction of the transport current applied, with increasing velocity as the current is further increased. At sufficiently high currents, superconductivity is completely destroyed, and the sample ends up in the normal state. In this paper, the first timeresolved measurements of voltage signals induced by the motion of single flux domains are reported. A stability analysis of the superconducting state based on the “Gibbs free energy barrier model” describes the temporal voltage profile generated by a single flux domain, which is solitarily moving across the sample cross-section, as well as the superimposed signals of a series of competing domains, existing simultaneously in the sample. In the latter case, the interaction among the flux domains is taken into account by a monopole ansatz. Studying the onset of the breakdown of superconductivity in type I materials, an oscillatory behavior of the domain size was found. After a few periods, these transients change into a stationary number of flux quanta per domain.