Josephson vortices and solitons inside pancake vortex lattice in layered superconductors

Abstract

In very anisotropic layered superconductors a tilted magnetic field generates crossing vortex lattices of pancake and Josephson vortices (JVs). We study the properties of an isolated JV in the lattice of pancake vortices. JV induces deformations in the pancake vortex crystal, which, in turn, substantially modify the JV structure. The phase field of the JV is composed of two types of phase deformations: the regular phase and vortex phase. The phase deformations with smaller stiffness dominate. The contribution from the vortex phase smoothly takes over with increasing magnetic field. We find that the structure of the cores experiences a smooth yet qualitative evolution with decrease of the anisotropy. At large anisotropies pancakes have only small deformations with respect to position of the ideal crystal while at smaller anisotropies the pancake stacks in the central row smoothly transfer between the neighboring lattice positions forming a solitonlike structure. We also find that even at high anisotropies pancake vortices strongly pin JVs and strongly increase their viscous friction.

Parametric amplification of vortex-antivortex pair generation in a Josephson junction

“…Similar effects of Abrikosov vortices on the critical current in layered superconductors have been investigated in the past [44][45][46][47][48][49][50][51][52][53]. In the present study, we focus on the nucleation and evolution of the resistive regime (i.e., at applied currents in the vicinity and above j c ).…”

“…In such a setup, the Abrikosov vortex can be inserted using different experimental techniques (e.g., by field cooling, by passing a large current through the system [44], or by using laser or electron beams [45]) and is trapped by the hole. It is already well known that a small perpendicular magnetic field can strongly affect both the static and the dynamic properties of the Josephson junction, due to the penetration of vortices (also known as pancake vortices in the case of very thin layers) [44][45][46][47][48][49][50][51][52][53]. Their effect is strongly reduced by introducing columnar defects [47], which align the Abrikosov vortices perpendicularly to the junction, thus diminishing the phase and magnetic field variations across the junction.…”

Critical current of layered superconductor with defects in tilted magnetic field

“…According to theoretical studies [4][5][6][7][8][9][10], pancake vortices are generated by c-axis field and Josephson vortices are generated by in-plane component. Josephson vortices are parallel to superconducting layers (ab-plane) and located in the inter-layer spacing.…”

“…Theoretical studies [4][5][6][7][8][9][10] show that layered superconductors have a rich phase diagram in tilted magnetic field. The structure of vortex lattice is defined by the parameter  J , which is the ratio of London, , and Josephson,  J =s, lengths [5].…”

Disorder and thermally driven melting of the flux-line lattice in anisotropic layered superconductors

“…[1][2][3] It has been widely accepted that at low temperatures and low magnetic fields, these vortices, which interact both magnetically and through Josephson coupling, align into a 3D linelike elastic lattice without dislocations, which is called the quasilong-range ordered Bragg glass ͑BG͒ phase. However, undergoing a thermally driven or a disorder driven condition, the FLL may melt into an entangled vortex liquid ͑VL͒ or an entangled vortex solid ͑VG͒ phase.…”