Fluctuating pancake vortices revealed by dissipation of the Josephson vortex lattice

Abstract

In strongly anisotropic layered superconductors in tilted magnetic fields, the Josephson vortex lattice coexists with the lattice of pancake vortices. Due to the interaction between them, the dissipation of the Josephson vortex lattice is very sensitive to the presence of the pancake vortices. If the c-axis magnetic field is smaller than the corresponding lower critical field, the pancake stacks are not formed but the individual pancakes may exist in the fluctuational regime either near the surface in large-size samples or in the central region for small-size mesas. We calculate the contribution of such fluctuating pancake vortices to the c-axis conductivity of the Josephson vortex lattice and compare the theoretical results with measurements on small mesas fabricated out of Bi 2 Sr 2 CaCu 2 O 8+δ crystals. A fingerprint of fluctuating pancakes is a characteristic exponential dependence of the c-axis conductivity observed experimentally. Our results provide strong evidence of the existence of the fluctuating pancakes and their influence on the Josephson vortex lattice dissipation.

Negative correlation between enhanced crossover temperature and fluctuation-free critical current of the second switch in Bi2Sr2CaCu2O${}_{8+\delta }$ intrinsic Josephson junction

“…In Bi2212, superconducting CuO 2 layer and insulating BiO layer are alternately stacked at the atomic scale. Couplings between the IJJs due to the thin superconducting CuO 2 layer cause various phenomena peculiar to IJJ stacks [5][6][7][8][9][10]. It is considered that the stacked IJJs are coupled both inductively and capacitively [11,12].…”

“…The origin of the inductive coupling is the penetration of inplane current over neighboring IJJs. A Josephson vortex lattice is a typical example of the result of the inductive coupling [8]. This effect can be embedded into the maximum Josephson current density J c , which gives the Josephson coupling energy E J .…”

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.…”

Terahertz Radiations and Switching Phenomena of Intrinsic Josephson Junctions in High-Temperature Superconductors: Josephson Phase Dynamics in Long- and Short-Ranged Interactions

“…In particular, since bismuth-based superconductors with large anisotropy can extract individual properties of IJJs and have an ideal tunnel barrier for Josephson junctions, researchers around the world, including the author, have been studying IJJs in bismuth-based high-𝑇 𝑐 superconductors. Particularly characteristic phenomena are the multi-branched currentvoltage characteristics, the quasiparticle spectrum directly † Graduate School of Engineering, Kyoto University indicating the superconducting gap [4], [5], electromagnetic absorption called Josephson plasma resonance [6]- [8], and the two-dimensional nature of vortex penetration [9]- [13]. These findings on the fundamental physical properties of IJJ systems provided the basis for terahertz electromagnetic wave emission by coherent oscillation [14]- [20], which was later demonstrated by the authors.…”