Resistive current states in wide superconducting films in zero magnetic field

Abstract

The temperature dependence of the current–voltage characteristics of high-quality thin films of tin from7 to 50 µm thick are investigated in the absence of an external magnetic field. For the first time, wehave experimentally observed phase slip centres (PSCs) and phase slip lines (PSLs) on thesame superconducting tin film with known parameters in the temperature intervalscorresponding to the mechanisms of their formation and existence. We have shown that thestates of a wide film with increasing transport current appear in the following order: thesuperconducting state for current less than critical; the resistive vortex state forcurrent more than critical, but less than maximum current for the uniform fluxflow (instability current); the critical state due to the onset of instability of thesteady pattern of viscous motion of the vortices; a vortex-free resistive state withPSLs for current more than instability current, but less than the upper criticalcurrent; and the normal state at a current higher than the upper critical current.