Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 21: Superconductivity: Poster Session

TT 21.7: Poster

Montag, 16. März 2015, 15:00–18:00, Poster B

Reduction of current-crowding effect in bended superconducting structures — •Ilya Charaev, Konstantin Ilin, and Michael Siegel — Institut für Mikro- und Nanoelektronische Systeme, Karlsruhe Institut für Technologie (KIT), Hertzstraße 16, 76187 Karlsruhe, Germany

Suppression of critical current Ic in superconducting structures with defects belongs to one of fundamental problems of superconductivity. One of mechanisms of suppression of Ic is a current-crowding effect, i.e. increase of current density in vicinity of defect. Detailed analysis of current-crowding effect in mesoscopic superconducting structures has been done by Clem in [1]. We demonstrate increase of the critical current of superconducting nanowires by an external magnetic field which is applied normally to the structure surface. The critical current of single-spiral nanowires with sharp bends, which play a role of artificially created defects, is 20% higher in magnetic field B = 25 mT than Ic of the same structure at B = 0 T. In case of single-spiral nanowires without sharp bends, the difference between Ic in magnetic field and Ic at B = 0 T was 5% only in good agreement with theoretical predictions. A detailed analysis of the influence of the magnetic field on transport properties of superconducting mesoscopic structures with artificial defects will be presented and discussed in terms of possible application of this effect for improvement of performance of superconducting nanowire single-photon detector.