Josephson Behavior of Phase-Slip Lines in Wide Superconducting Strips

Sivakov, A. G.; Glukhov, A. M.; Omelyanchouk, A. N.; Koval, Y.; Müller, Paul; Ustinov, A. V.

doi:10.1103/physrevlett.91.267001

Cited by 177 publications

(176 citation statements)

References 16 publications

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“…The oscillations of the order parameter connected by these two singularities are usually called kinematic vortices and it was proposed in Ref. 21 and experimentally observed by Sivakov et al 22 In this last reference it was estimated that a kinematic vortex can achieve a velocity v kv Ϸ 10 5 m / s which is two orders of magnitude higher than the velocity of an Abrikosov vortex v Av Ϸ 10 3 m / s. On the other hand, the velocity of a kinematic vortex is two orders of magnitude smaller than that of a Josephson vortex v Jv Ϸ 10 7 m / s. For the sample S 1 , the window during which the antivortex remains visible is ⌬t = 0.5517t 0 and the distance it travels is ⌬y = 2.875 ͑0͒; inserting T c = 3.72 K and ͑0͒ = 230 nm ͑the relevant parameters for Sn, which were used by Sivakov et al 22 ͒, the average velocity is v AV = 1.5ϫ 10 5 m / s. On the other hand, for the vortex exiting the antidot we obtain ⌬t = 0.2135t 0 and ⌬y = 1.625 ͑0͒; which gives v Vs = 2.2ϫ 10 5 m / s. Thus, the velocities involved in the annihilation process are very similar to those of kinematic vortices. It is worth noticing that the large velocities anticipated for the V-AV pair along the collision process, are similar to those developed during the early stage of a vortex avalanche, as observed by the authors of Ref.…”

Section: ͑2͒mentioning

confidence: 99%

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: ͑2͒mentioning

confidence: 99%

Vortex-antivortex annihilation dynamics in a square mesoscopic superconducting cylinder

et al. 2009

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“…This behavior is characteristic of phase-slip centers and has been extensively explored in the past. 12,13,16 Most likely, in our particular case, the steps in E coincide with the generation of phase-slip lines at the incommensurate moving vortex rows where vortices have a higher average mobility. 14 Interestingly, these phase-slip lines may coexist with slow moving vortex rows ͑commensurate rows͒.…”

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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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“…However, the R ab (T ) curves are very similar to those observed in the low-T c nanowires [16] or high-T c micro-bridges such as YBaCu 3 O 7−δ [17], for which the steps appeared due to the existence of the phase-slip centers or phase-slip lines. Hence, the sharp R ab (T ) drop can be interpreted as the SC transition, while the smooth R ab (T ) decrease could be associated with thermally activated phase slips.…”

Section: Fig 2 (Color Online)mentioning

confidence: 49%

“…Such steps can also be found on the return branches at relatively low temperatures 35 -37 K, where the Joule heating may affect the resistance. The successive steps on IVCs and the smooth decrease of R(T ) demonstrate characteristics typical for the phase slips as studied on the low-T c nanowires, high-T c quasi-1D and quasi-2D superconductors [16,17]. We will further discuss the phase-slip behavior in details in a forthcoming work.…”

Section: Fig 2 (Color Online)mentioning

confidence: 99%

Direct observation of the depairing current density in single-crystalline Ba0.5K0.5Fe2As2 microbridge with nanoscale thickness

Yuan

et al. 2013

Applied Physics Letters

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We investigated the critical current density (Jc) of Ba0.5K0.5Fe2As2 single-crystalline microbridges with thicknesses ranging from 276 to 18 nm. The J c of the microbridge with thickness down to 91 nm is 10.8 MA/cm 2 at 35 K, and reaches 944.4 MA/cm 2 by extrapolating Jc(T ) to T = 0 K using a two-gap s-wave Ginzburg-Landau model, well in accordance with the depairing current limit. The temperature, magnetic field, and angular-dependence of Jc(T, H, θ) indicated weaker field dependence and weakly anisotropic factor of 1.15 (1 T) and 1.26 (5 T), which also yielded the validity of the anisotropic Ginzburg-Landau scaling.The newly discovered Fe-based superconductors caused increasing attention due to their potential for applications, owing to high superconducting (SC) transition temperature (T c ), high upper critical fields (H c2 ), and a low critical current (J c ) anisotropy [1]. Compared with the layered cuprate family, although Fe-based superconductors have lower T c , they demonstrate nearly isotropic transport behavior [1]. Investigation of anisotropic J c is essential, from the view point of basic physics parameters and potential applications [2][3][4]. Generally, there are two main methods to explore the J c . The first one is to study patterned thin film micro-devices. The thin films have been fabricated successfully for several systems, including Fe(Se,Te) [2], Ba(Fe,Co) 2 As 2 [3], and LaFeAsO 1−x F x [4]. However, one can hardly obtain an ideal single-crystalline film, due to the presence of twins and low-angle grain boundaries resulting from the island-like growth process [5]. Although the existence of grain boundaries can enhance the J c by increasing pinning, the critical current exhibits exponential decay in the weak-link regime which poses a serious obstacle for practical applications. Up to now, the J c of Fe-based thin films was reported at the level of a few MA/cm 2 at 4.3 K [3][4][5]. The other method is to measure the J c indirectly from magnetization hysteresis loop (MHL) of single crystals. By using the Bean's model the J c can be evaluated from the vortex penetration profile [6], which is determined by pining force owing to the defects, grain boundary, and geometry of the materials. The J c value estimated from MHL remains as well of the order of a few MA/cm 2 at 4.3 K [7]. * Author to whom correspondence should be addressed. Electronic mail: Jun.Li@fys.kuleuven.beWe emphasize that both methods for J c determination are limited by the vortex motion in presence of a finite pining force, but not the intrinsic transport capability of the material, for which an exploration of the GinzburgLandau (GL) depairing current density (J GL dp ) is of great importance for understanding the existing limits for increasing J c [8][9][10]. The J GL dp corresponds to the critical pair-breaking current, which was theoretically estimated to be as high as 200 MA/cm 2 at 0 K for (Ba,K)Fe 2 As 2 [11]. This value is two orders of magnitude larger than previously reported J c 's. Generally, it is rather difficult t...

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Josephson Behavior of Phase-Slip Lines in Wide Superconducting Strips

Cited by 177 publications

References 16 publications

Vortex-antivortex annihilation dynamics in a square mesoscopic superconducting cylinder

Vortex-antivortex annihilation dynamics in a square mesoscopic superconducting cylinder

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

Direct observation of the depairing current density in single-crystalline Ba0.5K0.5Fe2As2 microbridge with nanoscale thickness

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