Phase diagram of a current-carrying superconducting film in absence of the magnetic field

Анотація

It is present the phase diagram for the current states of superconducting films, based on the experimental investigation of the resistive transitions induced by the transport current. It is found that a comparatively narrow film with the width w < 5λ_^ (T) (λ_^ is the penetration depth of the magnetic field) never enters the vortex state, but experiences direct transition from the purely superconducting state to the resistive state with phase-slip centers as soon as the current exceeds the critical Ginzburg–Landau current I_c^GL. The Meissner current state of the films of intermediate width, 5λ_^(T) < w < 10λ_^(T), transforms at I > 0.8I_c^GL to the vortex resistive state which exists within the current interval 0.8I_c^GL < I < I_m, where the value of the upper critical current is in a good agreement with the heory. The vortex state of wide films, w > 10λ_^, is realized within the current region I_c^AL < I < I_m, where I_c^AL is the transition point to the vortex state calculated for the limiting case w >> λ _^. At I > I_m, the films with the width w > 5λ_^(T) enter a vortex-free resistive state with phase-slip lines.