Kinematic vortex-antivortex lines in strongly driven superconducting stripes

Berdiyorov, Golibjon; Miloševıć, M. V.; Peeters, F. M.

doi:10.1103/physrevb.79.184506

Cited by 95 publications

(160 citation statements)

References 27 publications

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“…6, who reported velocities as large as 1.8ϫ 10 5 m / s for avalanches in YBCO films. Very recently, Berdiyorov et al 23 have investigated the activation of a kinematic vortex by using a transport current along a superconducting stripe, obtaining experimental results very close to our estimates.…”

Section: ͑2͒supporting

confidence: 56%

Vortex-antivortex annihilation dynamics in a square mesoscopic superconducting cylinder

et al. 2009

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The dynamics of the annihilation of a vortex-antivortex pair is investigated. The pair is activated magnetically during the run of a simulated hysteresis loop on a square mesoscopic superconducting cylinder with an antidot inserted at its center. We study the nucleation of vortices and antivortices by first increasing the magnetic field, applied parallel to the axis of the sample, from zero until the first vortex is created. A further increase in the field pulls the vortex in, until it reaches the antidot. As the polarity of the field is reversed, an antivortex enters the scene, travels toward the center of the sample, and eventually the pair is annihilated. Depending on the sample size, its temperature, and Ginzburg-Landau parameter, the vortex-antivortex encounter takes place at the antidot or at the superconducting sea around it. The position and velocity of the vortex and antivortex singularities were evaluated as a function of time. The current density, magnetization, and orderparameter topology were also calculated. Achieving a deep understanding of the nucleation and propagation of vortices in real superconductors is a truly complex task, since these entities interact with almost everything: first, with the surface of the specimen, to surpass it; upon entrance, with other vortices that might have already penetrated, and also with defects, which might attract them and even act as pinning centers. Additional difficulties to emulate the problem arise from the fact that vortices generate heat while propagating, what can be harmful to the robustness of the superconducting properties, if not catastrophic, as is the case of vortex avalanches observed in some superconducting films. [1][2][3][4][5][6] It is quite common, however, that the existence of pinning potentials represent a beneficial feature, since vortices can thus be prevented from undergoing dissipative motion. An interesting approach to the problem, which enables one to address most specificities without excessive complexity, is to work in the small universe of mesoscopic samples. In such an ambient, one can accommodate the essential ingredients: relatively important surface-tovolume ratio, only a few vortices on scene, and a number of defects-the so-called antidots-usually arranged in a regular pattern. Furthermore, one can study the interaction of an individual vortex-antivortex ͑V-AV͒ pair and, eventually, witness their mutual annihilation.Recently, there have been many studies about V-AV configurations in mesoscopic superconductors ͑see for instance Refs. 7-11͒. The authors of these references have found that vortices and antivortices may coexist in equilibrium in configurations which look like a V-AV molecule. A somewhat common approach is to assume an a priori configuration and minimize the free energy in terms of some relevant parameter for which the V-AV molecule is a stable configuration. Here, we will focus in a rather different approach concerning more with the dynamics of a V-AV encounter. The aim of the present work is to elucidate the de...

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Section: ͑2͒supporting

confidence: 56%

Vortex-antivortex annihilation dynamics in a square mesoscopic superconducting cylinder

et al. 2009

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“…The Lorentz force drives the nucleated vortex towards the outer corner of the sample where it leaves the sample (panel 2), but this motion is slow and weakly dissipative. The nucleation rate of vortices in the inner corner increases with further increasing the applied current, and at sufficiently large current (labeled j cd ) the system transits to a higher dissipative state with a larger voltage jump, characterized by fast-moving (kinematic) vortices (see panel 3) [13,20]. We point out that the critical current j c decreases considerably with increasing width of the sample, while j cd only moderately decreases (see dashed curve in Fig.…”

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confidence: 93%

Spatially dependent sensitivity of superconducting meanders as single-photon detectors

Berdiyorov

Miloševıć

Peeters

2012

Applied Physics Letters

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The photo-response of a thin current-carrying superconducting stripe with a 90-degree turn is studied within the time-dependent Ginzburg-Landau theory. We show that the photon acting near the inner corner (where the current density is maximal due to the current crowding [J. R. Clem and K. K. Berggren, Phys. Rev. B 84, 174510 (2011)]) triggers the nucleation of superconducting vortices at currents much smaller than the expected critical one, but does not bring the system to a higher resistive state and thus remains undetected. The transition to the resistive state occurs only when the photon hits the stripe away from the corner due to there uniform current distribution across the sample, and dissipation is due to the nucleation of a kinematic vortex-antivortex pair near the photon incidence. We propose strategies to account for this problem in the measurements.PACS numbers: 74.78. Na, 74.25.Fy Superconducting current-carrying thin-film stripes have recently received a revival of interest due to their promising application for single-photon detection [1] with a high maximum count rate, broadband sensitivity, fast response time and low dark counts [2][3][4]. The singlephoton absorption event leads to the formation of a nonequilibrium "hotspot" with suppressed superconductivity, the area of which grows in time, forming a normal belt across the strip [5]. The latter leads to redistribution of the current between the now resistive superconductor and a parallel shunt resistor, where a voltage pulse is detected, before a hotspot region cools down (on a timescale of few hundred picoseconds [6]) and the system returns to its initial superconducting state. Although the hotspot mechanism nicely explains the photon detection in the visible and near UV range, the detection mechanism in the near-infrared range is still debated (see e.g. Ref. [7] and references therein). Superconducting fluctuations, e.g., excitation of superconducting vortices [8][9][10][11][12], have been put forward as an explanation. Dissipative crossing of such vortices, which hop over the edge barrier, or are created due to the unbinding of thermally activated vortex-antivortex pairs, provides a good description of the experiment [10]. This vortex-based mechanism was also shown to be the dominating origin for dark counts [11,12,14], which leads to decoherence in the photon detection process.To increase the efficiency of the photon counting, detectors are usually fabricated as a meandering superconducting wire [3]. However, these structures are vulnerable to edge imperfections [3], which significantly reduce the photon counting rate. Moreover, the critical current in these systems is mostly determined by sharp inner corners where the supercurrent density is maximal due to current crowding [15,16]. While the appearance of edge imperfections can be reduced by present day technology [3], the effect of current crowding in such meandering geometries still demands further investigations.In this work we therefore study the effect of the turns of a meandering s...

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“…Clearly, both regimes, V and N, cannot be properly described by molecular dynamics approximations and the incorporation of the GinzburgLandau formalism is needed. 14,15 In order to investigate the region of stability of all these regimes we have performed measurements at different magnetic fields and temperatures. Figure 2 summarizes the different possible responses obtained in our particular system.…”

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confidence: 99%

Transition from turbulent to nearly laminar vortex flow in superconductors with periodic pinning

et al. 2009

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We revisit the vortex dynamics in Al thin films containing an artificial periodic array of antidots by means of electrical transport measurements. We clearly identify a turbulent to laminarlike vortex flow transition which manifests itself as a negative differential resistivity. This transition is accompanied by a strong irreversibility in the voltage-current characteristics. The dynamical phase diagrams obtained as a function of commensurability, temperature, and driving force are in good agreement with the early predictions by Reichhardt et al. ͓Phys. Rev. Lett. 78, 2648 ͑1997͔͒ based on molecular dynamic simulations. DOI: 10.1103/PhysRevB.80.140514 PACS number͑s͒: 74.25.Qt, 74.25.Dw, 74.40.ϩk, 74.78.Na The pioneering work of Giaever 1 provided the first experimental evidence that dc electrical resistance in type-II superconductors is a direct consequence of the motion of Abrikosov vortices.Extensive molecular dynamics ͑MD͒ simulations of array of vortices treated as overdamped objects interacting repulsively with each other and moving over a predefined potential landscape have proven to be a remarkably successful tool to describe the vortex dynamics in all sort of superconductors. 2 Superconductors with a periodic array of pinning centers represent a unique playground to investigate the interaction between vortices and pinning sites. [3][4][5] Early MD simulations for this particular system by Reichhardt et al. 6,7 predicted a remarkable property, namely, the existence of a dynamic transition from a highly dissipative disordered vortex flow at low driving forces to a less dissipative state of ordered flow where pinned vortices coexist with fast solitonlike excitations at higher currents. The sequence in which these dynamical phases appear is highly nontrivial and even counterintuitive since it implies a reduction of the average vortex mobility by increasing the driving force.In spite of the great deal of attention that this fascinating discovery has received in the superconducting community, so far there has been no experimental confirmation of it. A possible cause, recently pointed out by Misko et al.,8,9 is that strong heating or disorder effects can mask this effect. In this Rapid Communication we provide unambiguous experimental evidence that a superconducting film with a periodic array of antidots exhibits a clear turbulent to laminarlike vortex flow transition provided that heat removal is efficient. This transition appears as a negative differential resistivity in the current-voltage characteristics. We demonstrate that the loci of the dynamic transitions in a magnetic field-temperature phase diagram are highly sensitive to the pinning strength and commensurability of the system. At high bias currents the simplified model of a vortex as a pointlike classical particle which ignores the internal structure of the vortex and its elastic nature seems to fail and more realistic approaches, such as time dependent Ginzburg-Landau formalism, become necessary.The investigated sample consists of an Al film of...

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Kinematic vortex-antivortex lines in strongly driven superconducting stripes

Cited by 95 publications

References 27 publications

Vortex-antivortex annihilation dynamics in a square mesoscopic superconducting cylinder

Vortex-antivortex annihilation dynamics in a square mesoscopic superconducting cylinder

Spatially dependent sensitivity of superconducting meanders as single-photon detectors

Transition from turbulent to nearly laminar vortex flow in superconductors with periodic pinning

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