Dresden 2009 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 27: Superconductivity: Vortex Dynamics, Vortex Phases, Pinning
TT 27.1: Vortrag
Mittwoch, 25. März 2009, 14:00–14:15, HSZ 105
Vortex-vortex interaction in thin superconducting films — •Ernst Helmut Brandt — Max-Planck-Institut für Metallforschung, Stuttgart
The interaction between Pearl vortices in thin superconducting films is revisited. For infinitely extended films this problem was solved by Judea Pearl [1] who obtained the sheet current J(r) around the vortex and the force Φ0 J(r) on a second vortex with magnetic flux Φ0 and at distance r in terms of the two rarely used Bessel functions S1 and N1. It is shown that the interaction potential V(r) and force −V′(r) can be approximated with high precision in the entire range of r by a simple logarithm. This expression directly shows the correct limits V(r)=(Φ02/µ0) ln(2.27 Λ/r)/(2πΛ) for r ≪ Λ and V(r) = Φ02/(µ0 π r) for r ≫ Λ. Here Λ = λ2 /d is the effective penetration depth, λ the London depth, and d < λ the film thickness. The effect of finite film size on the vortex interaction is discussed. The interaction now depends not only on the distance r but on both vortex positions and on the film shape [2]. It is shown how the vortex interaction in finite films of any shape and size can be computed.
[1] J. Pearl, Appl. Phys. Lett. 5, 65 (1964).
[2] E. H. Brandt, Phys. Rev. B 72, 024529, 1-12 (2005).