Josephson vortex lattice melting in Bi-2212 probed by commensurate oscillations of Josephson flux-flow

Abstract

We studied the commensurate semi-fluxon oscillations of Josephson flux-flow (JFF) in a Bi-2212 stacked structures near $T_c$ as a probe of melting of Josephson vortex lattice (JVL). We found that oscillations exist above 0.5T. The amplitude of oscillations is found to decrease gradually with temperature and to turn to zero without any jump at $T=T_0$, 3.5K below the resistive transition temperature $T_c$ indicating the phase transition of the second order. This characteristic temperature $T_0$ is identified as the Berezinskii-Kosterlitz-Thouless (BKT) transition temperature, $T_{BKT}$, in elementary superconducting layers of Bi-2212 at zero magnetic field. On the base of these facts we infer that melting of triangular Josephson vortex lattice occurs via the BKT phase with formation of characteristic flux loops containing pancake vortices and anti-vortices. The $B-T$ phase diagram of the BKT phase found out from our experiment is consistent with theoretical predictions.

arXiv comment5 pages including 5 figures, accepted to JETP letters

References in corpus (5)

• Periodic Oscillations of Josephson-Vortex Flow Resistance in Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+y}$
• Possible critical point in phase diagrams of interlayer Josephson-vortex systems in high-Tc superconductors
• Probing quasiparticle dynamics in Bi2Sr2CaCu2O(8+delta) with a driven Josephson vortex lattice
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• Novel features of Josephson flux-flow in Bi-2212: contribution of in-plane dissipation, coherent response to mm-wave radiation, size effect

Cited by in corpus (4)

• Magnetic oscillations of critical current in intrinsic Josephson-junction stacks
• Josephson vortex lattice in layered superconductors
• Density functional theory for freezing transition of vortex-line liquid with periodic layer pinning
• Collective Josephson vortex dynamics in a finite number of intrinsic Josephson junctions