Restoration of the superconducting order parameter after a supercritical current pulse

Abstract Superconducting filaments submitted to larger-than-critical current steps switch, after an appreciable delay t d , into a non-uniform state where dissipation concerns only a limited length (phase-slip region). We have studied this transition and the corresponding relaxation in c-axis textured YBa 2 Cu 3 O x films grown on MgO substrates. A two-pulse method is used to probe the restoration of the order parameter in the absence of any current. A clearly non-thermal memory effect is observed for not too long a pulse separation. In the presence of a superimposed dc current, we found the resistive state to evolve according to one of the scenarii: (a) be sustained by self-heating; return (b) slowly or (c) suddenly into a zero resistance state. These investigations are intended to help describing the non-equilibrium state of the superconducting filament