Influence of artificial pinning on vortex lattice instability in superconducting films

Silhanek, Alejandro; Leo, Antonio; Grimaldi, Gaia; Berdiyorov, Golibjon; Miloševıć, M. V.; Nigro, A.; Pace, S.; Verellen, Niels; Gillijns, Werner; Metlushko, V.; Ilić, B.; Zhu, Xiaobin; Moshchalkov, Victor

doi:10.1088/1367-2630/14/5/053006

Cited by 54 publications

(79 citation statements)

References 28 publications

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“…In addition, while in Ref. [19] we demonstrated how pinning can give rise to an unexpected field dependence of a well-defined critical vortex velocity, in the present work we unveil experimentally and theoretically the origin of the observed multiple voltage jumps occuring at different critical vortex velocities. In particular, we find that a LO instability as manifested by a unique jump to the normal state at (J * ,V * ), can only occur at low fields where the effective pinning is stronger.…”

supporting

confidence: 57%

“…This prediction has been indeed observed in many different superconducting materials, [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] thus demonstrating the universal character of this phenomenon. According to the LO model, the current density J * and the voltage V * at the point where the instability is triggered, are uniquely defined.…”

Section: Introductionmentioning

confidence: 52%

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Onset, evolution, and magnetic braking of vortex lattice instabilities in nanostructured superconducting films

et al. 2015

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In 1976 Larkin and Ovchinnikov [Sov. Phys. JETP 41, 960 (1976)] predicted that vortex matter in superconductors driven by an electrical current can undergo an abrupt dynamic transition from a flux-flow regime to a more dissipative state at sufficiently high vortex velocities. Typically this transition manifests itself as a large voltage jump at a particular current density, so-called instability current density J * , which is smaller than the depairing current. By tuning the effective pinning strength in Al films, using an artificial periodic pinning array of triangular holes, we show that a unique and well defined instability current density exists if the pinning is strong, whereas a series of multiple voltage transitions appear in the relatively weaker pinning regime. This behavior is consistent with time-dependent Ginzburg-Landau simulations, where the multiple-step transition can be unambiguously attributed to the progressive development of vortex chains and subsequently phase-slip lines. In addition, we explore experimentally the magnetic braking effects, caused by a thick Cu layer deposited on top of the superconductor, on the instabilities and the vortex ratchet effect.

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confidence: 57%

Section: Introductionmentioning

confidence: 52%

Onset, evolution, and magnetic braking of vortex lattice instabilities in nanostructured superconducting films

et al. 2015

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“…In that case of Al superconducting film with underneath magnetic pinning, we observed a different behavior of I *( H ) and V *( H ). In particular, despite the fact that I c was affected by pinning influence, I * resulted practically insensitive to changes in pinning strength 42 , but not V *( H ) that followed the expected trend as a function of pinning strength. In the absence of a complete theoretical description of flux flow instability, able to take into account not only the material pinning influence but also the multiband peculiar nature of this material, we cannot exclude that the multiband character of Fe(Se,Te), rather different from BSCCO, may influence the electronic mechanism at the base of such instability.…”

Section: Discussionmentioning

confidence: 84%

“…In fact, the macroscopic quantity of I * plays the role of the energy supplied to the vortices in the flux flow motion just before the instability takes place, so that any distribution of pinning centers as well as their interactions with the moving vortices can influence such an instability point. In fact, we have previously reported on a tunable pinning strength effect, for example, on I *( H ) behavior 42 . In that case of Al superconducting film with underneath magnetic pinning, we observed a different behavior of I *( H ) and V *( H ).…”

Section: Discussionmentioning

confidence: 94%

Angular dependence of vortex instability in a layered superconductor: the case study of Fe(Se,Te) material

Grimaldi

Leo

Nigro

et al. 2018

Sci Rep

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Anisotropy effects on flux pinning and flux flow are strongly effective in cuprate as well as iron-based superconductors due to their intrinsically layered crystallographic structure. However Fe(Se,Te) thin films grown on CaF2 substrate result less anisotropic with respect to all the other iron based superconductors. We present the first study on the angular dependence of the flux flow instability, which occurs in the flux flow regime as a current driven transition to the normal state at the instability point (I*, V*) in the current-voltage characteristics. The voltage jumps are systematically investigated as a function of the temperature, the external magnetic field, and the angle between the field and the Fe(Se,Te) film. The scaling procedure based on the anisotropic Ginzburg-Landau approach is successfully applied to the observed angular dependence of the critical voltage V*. Anyway, we find out that Fe(Se,Te) represents the case study of a layered material characterized by a weak anisotropy of its static superconducting properties, but with an increased anisotropy in its vortex dynamics due to the predominant perpendicular component of the external applied magnetic field. Indeed, I* shows less sensitivity to angle variations, thus being promising for high field applications.

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“…At 35 and 36 K, the V (I) curve jumps from SC (V =0) to normal state (V = 0) directly at a critical value of current (I c ), with absence of any gradual dissipation process. After slightly increasing temperature to 37 K, a small resistance appears when the bias current is applied close to I c , which, probably, corresponds to the nonlinear flux-flow regime [18]. Note that for T ≤37 K, when the current returns along a resistive branch back to the SC state at a return current I r , a pronounced hysteresis of IVCs demonstrates a Josephson-junction-like behavior [9].…”

Section: Fig 2 (Color Online)mentioning

confidence: 95%

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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Influence of artificial pinning on vortex lattice instability in superconducting films

Cited by 54 publications

References 28 publications

Onset, evolution, and magnetic braking of vortex lattice instabilities in nanostructured superconducting films

Onset, evolution, and magnetic braking of vortex lattice instabilities in nanostructured superconducting films

Angular dependence of vortex instability in a layered superconductor: the case study of Fe(Se,Te) material

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

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