Reference : Pinning centers produced by magnetic microstructures
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Physics
Pinning centers produced by magnetic microstructures
Silhanek, Alejandro mailto [Katholieke Universiteit Leuven - KUL > > > >]
Van de Vondel, J. [> > > >]
Leo, A. [> > > >]
Ataklti, G. W. [> > > >]
Gillijns, W. [> > > >]
Moshchalkov, V. V. [ > > ]
Superconductor Science and Technology
Institute of Physics
Yes (verified by ORBi)
United Kingdom
[en] superconductivity
[en] We investigate the flux pinning and dynamic properties of superconducting vortices in an Al film with an array of magnetic bars deposited on top. The dimensions of each bar are chosen in such a way that they host a single magnetic domain. These micromagnets are distributed periodically in a rectangular array with 0.5 mu m separation parallel to the longest side of the bars and displaced laterally by a distance w. We show that, for w > Lambda, where Lambda is the effective field penetration depth, the pinning strength is almost independent of w whereas the critical temperature at zero field, T(c)(0), decreases as similar to w(-1). For w < Lambda the opposite behavior is observed, i.e. T(c)(0) seems to saturate to a nearly w-independent value and the transition from large to small w is accompanied by a large suppression of the critical current j(c) together with a clear change in the shape of the current-voltage characteristics. In particular, the substantial weakening of the pinning potential for w < Lambda gives rise to an unexpected flux flow response. The field evolution of this regime allows us to determine whether the magnetic bars induce vortex-antivortex pairs in the system. The present findings suggest that practical application of magnetic pinning centers are restricted to low field values.

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