Field-enhanced critical parameters in magnetically nanostructured superconductors

Abstract

Within the phenomenological Ginzburg-Landau theory, we demonstrate the enhancement of superconductivity in a superconducting film, when nanostructured by a lattice of magnetic particles. Arrays of out-of-plane magnetized dots (MDs) extend the critical magnetic field and critical current the sample can sustain, due to the interaction of the vortex-antivortex pairs and surrounding supercurrents induced by the dots and the external flux lines. Depending on the stability of the vortex-antivortex lattice, a peak in the Hext-T boundary is found for applied integer and rational matching fields, which agrees with recent experiments [Lange et al., Phys. Rev. Lett. 90, 197006 (2003)]. Due to compensation of MDs- and Hext-induced currents, we predict the field-shifted jc-Hext characteristics, as was actually realized in previous experiment but not commented on [Morgan and Ketterson, Phys. Rev. Lett. 80, 3614 (1998)].

8 pages, 5 figures, to appear in Europhysics Letters

References in corpus (3)

• Nanoengineered magnetic-field-induced superconductivity
• Superconducting Wigner Vortex Molecule near a Magnetic Disk
• Vortex States of a Superconducting Film from a Magnetic Dot Array

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• Effects of chiral helimagnets on vortex states in a superconductor
• Dependence of Vortex States in Superconductors on a Chiral Helimagnet and an Applied Magnetic Field
• Effective penetration length and interstitial vortex pinning in superconducting films with regular arrays of defects