Electric currents and resistive states in thin superconductors Article uri icon

abstract

  • Properties of thin superconducting filaments carrying a d.c. electric current are considered. We study first the stability of the normal state in the current-carrying filament. It is shown that the phase transition from the normal into the superconducting or into the resistive state in the presence of a current is a first-order transition. The mechanism of the transition changes when the filament has a non-uniform structure; the normal state of a filament becomes unstable in this case below some critical current dependent on the type of inhomogeneity. We study then the resistive state in thin superconducting filaments. As is well known the usual superconducting state becomes impossible when the current exceeds the so-called Ginzburg-Landau critical current. Instead, either the normal or the so-called resistive state appears in the superconductor. In the resistive state, the mean electric field is non-zero in the superconductor. Nevertheless superconductivity is destroyed only in some separate points in the filament and at some moments of time. These points are known as phase-slip centres. Different physical mechanisms of the resistive state are reviewed. The main attention is paid to the microscopic theory and the dynamics of the resistive state. The current-voltage characteristics of the current-carrying superconducting filaments are calculated on the basis of the non-stationary microscopic theory considered. The voltage steps in current-voltage characteristics due to formation of new phase-slip centres in the superconductor are discussed. The possibility of low-frequency oscillations in the resistive state is briefly discussed. Moreover, we consider a rather simple model which demonstrates that the principle of minimum entropy production can be applied to determine otherwise unknown parameters of the system. © Taylor %26 Francis Group, LLC.

publication date

  • 1984-01-01