Europhys. Lett.
Volume 73, Number 2, January 2006
Page(s) 253 - 259
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 14 December 2005
Europhys. Lett., 73 (2), pp. 253-259 (2006)
DOI: 10.1209/epl/i2005-10390-9

Unzipping flux lines from extended defects in type-II superconductors

Y. Kafri1, 2, 3, D. R. Nelson1, 2 and A. Polkovnikov1, 4

1  Department of Physics, Harvard University - Cambridge, MA 02138, USA
2  Physicochimie Curie (CNRS-UMR168), Institut Curie, Section de Recherche 26 rue d'Ulm, 75248 Paris Cedex 05, France
3  Department of Physics, Technion - Haifa 32000, Israel
4  Department of Physics, Boston University - Boston, MA 02215, USA

received 5 October 2005; accepted 25 November 2005
published online 14 December 2005

With magnetic force microscopy in mind, we study the unbinding transition of individual flux lines from extended defects like columnar pins and twin planes in type-II superconductors. In the presence of point disorder, the transition is universal with an exponent which depends only on the dimensionality of the extended defect. We also consider the unbinding transition of a single vortex line from a twin plane occupied by other vortices. We show that the critical properties of this transition depend strongly on the Luttinger liquid parameter which describes the long-distance physics of the two-dimensional flux line array.

74.25.Qt - Vortex lattices, flux pinning, flux creep.
05.20.-y - Classical statistical mechanics.
74.25.-q - Properties of type I and type II superconductors.

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