Ultra-fast kinematic vortices in mesoscopic superconductors: the effect of the self-field

Abstract

Within the framework of the generalized time-dependent Ginzburg–Landau equations, we studied the influence of the magnetic self-field induced by the currents inside a superconducting sample driven by an applied transport current. The numerical simulations of the resistive state of the system show that neither material inhomogeneity nor a normal contact smaller than the sample width are required to produce an inhomogeneous current distribution inside the sample, which leads to the emergence of a kinematic vortex–antivortex pair (vortex street) solution. Further, we discuss the behaviors of the kinematic vortex velocity, the annihilation rates of the supercurrent, and the superconducting order parameters alongside the vortex street solution. We prove that these two latter points explain the characteristics of the resistive state of the system. They are the fundamental basis to describe the peak of the current–resistance characteristic curve and the location where the vortex–antivortex pair is formed.

Causes and Consequences of Ordering and Dynamic Phases of Confined Vortex Rows in Superconducting Nanostripes

“…When J reaches roughly 0.65J DP , the SN transitions to a fully normal state with a linear ohmic behaviour. Similar V-I curves have been observed both numerically [52] and experimentally for Nb-C microstrips that were fabricated using focused-ion-beam-induced deposition [38]. In real materials, the presence of disorder and defects changes the behaviour described in this work.…”

“…The results of our simulations of the vortex velocity as a function of the sourced current density are shown in Figure 12a. They evidence a linear dependence at lower values of J for both of the narrow SNs considered above (which is similar to the behaviour seen in [52,55]). However, when J is increased to intermediate values, we find a deviation from the linear dependence, which is due to the increasingly facilitated vortex tailgating.…”

Diagramas de fase J1(τ) y J1(γ) de un filme superconductor

“…La muestra está en presencia de una corriente continua Ja que se aplica uniformemente a través de los electrodos metálicos de ancho a = W (vea figura 1). La forma general de las ecuaciones Ginzburg-Landau dependientes del tiempo para sistemas en presencia de corrientes para el parámetro de orden 𝜓 y el potencial vectorial A, en su forma adimensional es [11], [12], [21], [22]: Figura 1. Esquema de la muestra estudiada.…”

“…L. Rodrigues y colaboradores estudiaron el papel del campo magnético propio inducido por las corrientes dentro de una muestra superconductora en presencia de una corriente externa aplicada. Encontraron que no se requiere inhomogeneidad del material para producir la aparición de un par cinemático vórtice-antivórtice [11].…”

Memristor-like behavior and negative resistance in a superconductor/insulator/ferromagnet device with a pinholes-governed interface

“…PSLs are considered the two-dimensional analogue to phase-slip centers [8], describing time-periodic suppressed superconductivity along a line perpendicular to the current direction that generates non-equilibrium quasiparticles [3]. Vortex streets are spontaneously nucleated pairs of vortices that move perpendicular to the current direction [3,9,10]. These pairs are generated by the current-induced magnetic field, nucleate at the edges of the superconductor and annihilate at its center its center [4,6].…”