Temperature dependence of the critical current of the superconducting microladder in zero magnetic field: Theory and experiment

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Abstract
The largest supercurrent which can be injected into a superconducting microladder was calculated as a function of nodal spacing scrL and temperature for zero magnetic flux using (i) exact solutions of the Ginzburg-Landau equation in terms of Jacobian elliptic functions and (ii) approximate solutions in terms of hyperbolic functions. The agreement is good for scrL/ξ(T)T) is the temperature-dependent coherence length. Since solution (ii) is much simpler than solution (i), it is of considerable value when calculating critical currents of micronets with nodal spacings comparable to ξ(T). We find that the temperature-dependent critical current deviates significantly from the classical 3/2 power law of the Ginzburg-Landau theory. Preliminary experiments on a submicrometer ladder confirm such deviations.