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Crossing lattices, vortex chains, and angular dependence of melting line in layered superconductors

A. E. Koshelev
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Abstract

We investigate vortex structure and melting transition in very anisotropic layered superconductors at fields tilted with respect to the c-axis. We show that even a small in-plane field does not homogeneously tilt the vortex lattice but, instead, penetrates inside the superconductor in the form of Josephson vortices (JVs) similar to the Meissner state. At high c-axis magnetic field the phase field of the JV is built up from the phase perturbations created by displacements of pancake vortices. The crossing-lattices ground state leads to linear dependencies of the melting field and melting temperature on the in-plane field, in agreement with recent experimental observations. At small fields stacks of JVs accumulate additional pancake strings creating vortex rows with enhanced density. This mechanism explains the mixed chains-lattice state observed by Bitter decorations.

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A. E. Koshelev. 1999-04-08. Crossing lattices, vortex chains, and angular dependence of melting line in layered superconductors. https://doi.org/10.1103/physrevlett.83.187

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