Vortex Confinement in Planar S/F Hybrid Structures

ORAL

Abstract

We have investigated the effect of periodic stray fields of the ferromagnet on the vortex dynamics in superconductor/ferromagnet (S/F) systems. Magnetization measurements were performed using SQUID magnetometry for Permalloy/Niobium (Py/Nb) samples of varying Py domain widths and Nb thicknesses. The hysteresis loops show an increase of the critical current for some values of magnetic domain width and superconductor thickness in some portion of the H-T phase diagram. However, below a threshold temperature sudden jumps in magnetization are observed during a slow sweep of the external magnetic field, which indicate the occurrence of vortex avalanches. These avalanches have been confirmed by scanning probe microscopy and they can cause a collapse of the critical state below a threshold temperature. Static and dynamics of these systems will be discussed.

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Authors

  • Steven Moore

    Physics Department, Temple University, Philadelphia, PA 19122 USA, Physics Department, Temple University, Philadelphia, PA 19122, USA

  • Valentyn Novosad

    Materials Science Division, Argonne National Laboratory, Argonne, IL 60439 USA, Argonne National Laboratory, Argonne National Laboratory, Materials Science Division

  • V. Yefremenko

    Materials Science Division, Argonne National Laboratory, Argonne, IL 60439 USA, Argonne National Laboratory

  • Goran Karapetrov

    Physics Department, Drexel University, Philadelphia, PA 19104 USA, Physics Department, Drexel University, Drexel University, Physics Department, Drexel University, Philadelphia PA 19104, USA, Department of Physics, Drexel University and Institute of Electrical Engineering, Slovak Academy of Sciences

  • Maria Iavarone

    Physics Department, Temple University, Philadelphia, PA 19122 USA, Temple University, Physics Department, Temple University, Philadelphia, PA 19122, USA