Current driven transition from Abrikosov-Josephson to Josephson-like vortex in mesoscopic lateral S/S’/S superconducting weak links

Abstract

Vortices are topological defects accounting for many important effects in superconductivity, superfluidity, and magnetism. Here we address the stability of a small number of such excitations driven by strong external forces. We focus on Abrikosov-Josephson vortex that appears in lateral superconducting S/S’/S weak links with suppressed superconductivity in S’. In such a system the vortex is nucleated and confined in the narrow S’ region by means of a small magnetic field and moves under the effect of a force proportional to an applied electrical current with a velocity proportional to the measured voltage. Our numerical simulations show that when a slow moving Abrikosov-Josephson vortex is driven by a strong constant current it becomes unstable with respect to a faster moving excitation: the Josephon-like vortex. Such a current-driven transition explains the structured dissipative branches that we observe in the voltage-current curve of the weak link. When vortex matter is strongly confined phenomena as magnetoresistance oscillations and reentrance of superconductivity can possibly occur. We experimentally observe these phenomena in our weak links.

Dynamic transition of vortices into phase slips and generation of vortex-antivortex pairs in thin film Josephson junctions under dc and ac currents

“…For instance, radiation by AJ vortices can be enhanced as they move in a periodic magnetic potential of A vortices along grain boundaries 28,55 , whereas A vortices trapped perpendicular to the junction can result in generation of V-AV pairs in the presence of the applied electric current 56 . The result of this work may also pertain to the transition of A vortices driven by strong currents into chains of weakly coupled J vortices or phase slips in wide thin films [57][58][59][60][61][62][63] . In this case vortices moving along a self-induced channel of reduced order parameter behave as overdamped AJ vortices considered here.…”

Formation and Rearragement of Vortex Tubes in a 3D Mesoscopic Superconductor with a Central Weak Link

“…Theoretically, it has been shown that many different kinds of superconducting states can exist in mesoscopic samples [2,[5][6][7][8][9][10][11]. Vortices also show very rich static and dynamic behavior in the presence of a weak link [7,10,14]. It is well known properties of both superconducting and normal metals are modified due to the proximity effect [15] when they are in contact with each other.…”

Finite Element Treatment of Vortex States in 3D Mesoscopic Cylindrical Superconductors in a Tilted Magnetic Field

“…Recent theoretical studies have shown that vortex-antivortex states can also be stabilized in submicron superconductors even in a homogeneous magnetic field [17]. Vortices show very rich static and dynamic behavior in the presence of a weak link [9,12,18]. A weak link is commonly achieved by two superconducting layers separated by a normal metallic layer, or a weak superconducting region.…”

“…Since recently, such superconducting samples (cylindrical wires and tubes) were experimentally realized [22]. In this paper, we investigate the 3D time-dependent Ginzburg-Landau (TDGL) equations in the order parameter ψ of the Cooper-pair condensate for fully 3D cylindrical samples in the basis of finite-element method (FEM) [12,23], which is proved to be an effective method for the mesoscopic superconductors with a complex geometry [23].…”

“…Due to the interaction between vortices and sample boundaries, vortex configurations strongly dependent on the size and geometry of mesoscopic samples whose dimensions are of the order of the penetration depth λ or the coherence length ξ. For example, strong confinement leads to the formation of the giant vortex state [3][4][5][6][7] and multivortex state [8][9][10][11][12][13][14], which are energetically less favorable in bulk type-II superconductors [15]. The vortex-antivortex states are easily stabilized in an inhomogeneous magnetic field [16].…”