Critical-current reduction in thin superconducting wires due to current crowding

Critical-current reduction in thin superconducting wires due to current crowding

Transport and magnetic critical current in superconducting MgB2 wires

Direct comparison of the magnetic and transport critical current density (Jc) for the same pieces of copper-sheathed MgB2 wires shows a large discrepancy in magnitude and field dependence of the two. The value of magnetic Jc can differ from the value of transport Jc by a factor of 10 or more. This discrepancy does not occur merely because of the difference in the voltage at which the magnetic a...

Superconducting current in narrow proximity wires

The critical supercurrent in proximty-wires shows a surprising temperature dependence in the experiment [1]. This observation has lead to speculation whether there are new e ects involved and/or the usual criterion for the dirty limit is not valid for this type of systems. We propose a simple SNS-model for this system and show analytically, that this unexpected scaling is already contained in a...

Current dissipation in thin superconducting wires: A numerical evaluation using the string method

Current dissipation in thin superconducting wires is numerically evaluated by using the string method, within the framework of time-dependent Ginzburg-Landau equation with a Langevin noise term. The most probable transition pathway between two neighboring current-carrying metastable states, continuously linking the Langer-Ambegaokar saddle-point state to a state in which the order parameter van...

Critical current densities in superconducting materials

We discuss recent research in the area of critical current densities (JC) in superconductors. This shall cover recent work on newly discovered superconductors, as well as on the magnetic-field dependence of JC .