Predicted field-dependent increase of critical currents in asymmetric superconducting nanocircuits

TitlePredicted field-dependent increase of critical currents in asymmetric superconducting nanocircuits
Publication TypeJournal Article
Year of Publication2012
AuthorsClem JR, Mawatari Y, Berdiyorov GR, Peeters FM
Journal TitlePhysical Review B
Volume85
Pages144511
Date Published04
Type of ArticleArticle
ISBN Number1098-0121
Accession NumberWOS:000302611100004
Keywordsbarriers, EDGE, filaments, films, flux-flow noise, ii, state, superconductors, surface-defects, type-2 superconductors, vortex entry
Abstract

The critical current of a thin superconducting strip of width W much larger than the Ginzburg-Landau coherence length xi but much smaller than the Pearl length Lambda = 2 lambda(2)/d is maximized when the strip is straight with defect-free edges. When a perpendicular magnetic field is applied to a long straight strip, the critical current initially decreases linearly with H but then decreases more slowly with H when vortices or antivortices are forced into the strip. However, in a superconducting strip containing sharp 90 degrees or 180 degrees turns, the zero-field critical current at H = 0 is reduced because vortices or antivortices are preferentially nucleated at the inner corners of the turns, where current crowding occurs. Using both analytic London-model calculations and time-dependent Ginzburg-Landau simulations, we predict that in such asymmetric strips the resulting critical current can be increased by applying a perpendicular magnetic field that induces a current-density contribution opposing the applied current density at the inner corners. This effect should apply to all turns that bend in the same direction.

URL<Go to ISI>://WOS:000302611100004
DOI10.1103/PhysRevB.85.144511
Alternate JournalPhys. Rev. B