Fluxons in thin-film superconductor-insulator superlattices

Abstract

In a system of thin alternating layers of superconductors and insulators the equations describing static and dynamic fluxon solutions are derived. The approach, represented by a useful compact matrix form, is intended to describe systems fabricated for example of niobium or niobium-nitride thin films; in the limit of ultrathin superconductor films it may give a model for describing fluxon motion in layered high-T, superconductors. Numerical examples of current versus voltage curves to be expected in such an experiment are presented.

Dynamic structure selection and instabilities of driven Josephson lattice in high-temperature superconductors

“…Usually, only dissipation due to the tunneling of quasiparticles between the layers is taken into account in consideration of the dynamics of the Josephson vortices. 22,19 However, in high-T c superconductors the in-plane component of the quasiparticle conductivity σ ab is strongly enhanced in the superconducting state as compared to the normal conductivity due to the reduction of the phase space for scattering. This enhancement was observed in Y Ba 2 Cu 3 O 7 23 and in BSCCO 24 .…”

“…18 The phase dynamics in layered superconductors is described by the coupled sine-Gordon equations. 19,12,20,21,8,9 Two equivalent approaches have been used to derive these equations. In the first approach 19,12,20 the layered superconductor is modeled as a multilayered S-I-S-I-.…”

Terahertz wave emission from intrinsic Josephson junctions in high-Tcsuperconductors

“…Many theoretical models have been proposed to explain the IJJ effect [15,16] and the mechanism of THz wave generation from Bi2212 mesas [17][18][19][20][21][22][23][24][25][26]. One model is based on the modulation of the Josephson critical current density along the width of the mesa, which allows for the efficient excitation of the cavity resonance under zero magnetic fields [17].…”

Plasma resonance in anisotropic layeredhigh−Tcsuperconductors

“…II, the stacked junction system is described by the inductive coupling model by introducing a compact vector-matrix formalism. The description follows the previously published theory with respect to the inductive coupling model, 3 except that a more general expression for the external current bias terms is introduced. Next, the analytic form for plasma oscillations is presented, also using the compact vector-matrix notation and the results for some special cases are discussed.…”

“…2 An interesting case occurs when the thickness t of the superconducting ͑S͒ layer is comparable to or less than the magnetic penetration depth L , of the S layer. In such cases strong inductive coupling 3,4 can be expected among the Josephson junctions making the stack. In the case of a (Nb/AlO x /) n Nb stack, L is about 90 nm, and thus the condition of tϽ L can be realized easily.…”