On the Decoupling of Layered Superconducting Films in Parallel Magnetic Field

Abstract

The issue of the decoupling of extreme type-II superconducting thin films (${\lambda }_L\to \infty$) with weakly Josephson-coupled layers in magnetic field parallel to the layers is considered via the corresponding frustrated $XY$ model used to describe the mixed phase in the critical regime. For the general case of arbitrary field orientations such that the perpendicular magnetic field component is larger than the decoupling cross-over scale characteristic of layered superconductors, we obtain independent parallel and perpendicular vortex lattices. Specializing to the double-layer case, we compute the parallel lower-critical field with entropic effects included, and find that it vanishes exponentially as temperature approaches the layer decoupling transition in zero-field. The parallel reversible magnetization is also calculated in this case, where we find that it shows a cross-over phenomenon as a function of parallel field in the intermediate regime of the mixed phase in lieu of a true layer-decoupling transition. It is argued that such is the case for any finite number of layers, since the isolated double layer represents the weakest link.

29 pages of plain TeX, 2 postscript figures, improved discussion

References in corpus (1)

• Critical Behavior of the Flux-line Tension in Extreme Type-II Superconductors

Cited by in corpus (8)

• Deconfinement of Vortices with Continuously Variable Fractions of the Unit Flux Quanta in Two-Gap Superconductors
• Collective pinning of the vortex lattice by columnar defects in layered superconductors
• Fermion Analogy for Layered Superconducting Films in Parallel Magnetic Field
• Theory for Decoupling in High-T_c Superconductors from an Analysis of the Layered XY Model with Frustration
• Long-Range Order of Vortex Lattices Pinned by Point Defects in Layered Superconductors
• Nature of Decoupling in the Mixed Phase of Extremely Type-II Layered Superconductors
• Spin-density Wave in Ising-coupled Antiferromagnetic Chains
• Defective Vortex Lattices in Layered Superconductors with Both Point and Correlated Pins