Vortex Entry and Nucleation of Antivortices in a Mesoscopic Superconducting Triangle

Chibotaru, Liviu F.; Ceulemans, Arnout; Bruyndoncx, V.; Moshchalkov, Victor

doi:10.1103/physrevlett.86.1323

Cited by 139 publications

(103 citation statements)

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“…Theoretical studies [14][15][16][17][18][19] showed that different types of vortex states can appear in such samples: giant vortex states, multivortex states, combinations of giant and multivortex states, and even states where vortices and antivortices coexist. 14 In addition, it became clear that the stability of the different vortex states strongly depends on the sample shape.…”

Section: Introductionmentioning

confidence: 99%

Multivortex and giant vortex states near the expulsion and penetration fields in thin mesoscopic superconducting squares

et al. 2006

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The temperature dependence of the vortex penetration and expulsion magnetic fields are investigated, both theoretically and experimentally, for mesoscopic superconducting squares. The small-tunnel-junction method is used to determine the transition fields between the different vortex states. We found that the penetration fields decrease with increasing temperature, while the expulsion fields for a particular vorticity may increase, decrease or be independent of temperature. Using the Ginzburg-Landau theory we link the different temperature dependencies to the configuration of the vortex state, i.e. giant vortex state versus multivortex state. The vortex state consisting of four vortices has a larger stability region which is most pronounced in a certain hightemperature range.

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Section: Introductionmentioning

confidence: 99%

Multivortex and giant vortex states near the expulsion and penetration fields in thin mesoscopic superconducting squares

et al. 2006

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“…For superconductors expectations are even more spectacular. In macroscopic type-II superconductors a triangular lattice of single flux quanta is formed, whereas two kinds of fundamentally new vortex states have theoretically been predicted in mesoscopic superconductors where the sample size approaches the size of Cooper-pairs [2,3,4,5]; (i) multivortex states (MVSs) with a unique spatial arrangement of singly quantized vortices, and (ii) multiply quantized or giant vortex states (GVSs) with a single core in the center [6,7].Although several experimental techniques have been developed for observing these novel states [7,8,9,10,11,12,13], none of them has been able to make a clear distinction between MVSs and GVSs. In this Letter, we present the first experimental evidence for the existence of GVSs and MVSs in a circular disk, and demonstrate magnetic-field induced MVS-GVS and MVS-MVS transitions.…”

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confidence: 99%

“…Finally, we want to remark that our method can be applied to other geometries such as squares and triangles, in which antivortices might be stabilized for some vorticities [11,12,23,24].…”

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confidence: 99%

“…Although several experimental techniques have been developed for observing these novel states [7,8,9,10,11,12,13], none of them has been able to make a clear distinction between MVSs and GVSs. In this Letter, we present the first experimental evidence for the existence of GVSs and MVSs in a circular disk, and demonstrate magnetic-field induced MVS-GVS and MVS-MVS transitions.…”

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confidence: 99%

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Experimental Evidence for Giant Vortex States in a Mesoscopic Superconducting Disk

et al. 2004

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Response of a mesoscopic superconducting disk to perpendicular magnetic fields is studied by using the multiple-small-tunnel-junction method, in which transport properties of several small tunnel junctions attached to the disk are measured simultaneously. This allows us for the first experimental distinction between the giant vortex states and multivortex states. Moreover, we experimentally find magnetic field induced rearrangement and combination of vortices. The experimental results are well reproduced in numerical results based on the nonlinear Ginzburg-Landau theory.The appearance of vortices in various quantum systems, such as superconductors, superfluids and BoseEinstein condensates, is an intriguing phenomenon in nature. A conventional quantum vortex is singly quantized, having a core where the value of the order parameter decreases to zero, while its phase changes by 2π when encircling the core. Recently, an important breakthrough was established by the observation of doubly quantized vortex lines in superfluid 3 He-A[1]. For superconductors expectations are even more spectacular. In macroscopic type-II superconductors a triangular lattice of single flux quanta is formed, whereas two kinds of fundamentally new vortex states have theoretically been predicted in mesoscopic superconductors where the sample size approaches the size of Cooper-pairs [2,3,4,5]; (i) multivortex states (MVSs) with a unique spatial arrangement of singly quantized vortices, and (ii) multiply quantized or giant vortex states (GVSs) with a single core in the center [6,7].Although several experimental techniques have been developed for observing these novel states [7,8,9,10,11,12,13], none of them has been able to make a clear distinction between MVSs and GVSs. In this Letter, we present the first experimental evidence for the existence of GVSs and MVSs in a circular disk, and demonstrate magnetic-field induced MVS-GVS and MVS-MVS transitions. Our results are in good agreement with the theoretical prediction based on the nonlinear GinzburgLandau (G-L) theory.Here we used the multiple-small-tunnel-junction (MSTJ) method, in which several small tunnel junctions with high tunnel resistance are attached to a mesoscopic superconductor to simultaneously detect small changes in the local density of states (LDOS) under the junctions [14,15]. Since the LDOS depends on the local supercurrent density, the MSTJ method gives us information on the distribution of the supercurrent, which reflects the detailed vortex structure inside the disk. Figure 1 shows a schematic drawing and a scanning electron microscopy (SEM) image of the sample. Four normal-metal (Cu) leads are connected to the periphery of the superconducting Al disk through highly resistive small tunnel junctions, A, B, C, and D. The sample is designed to be symmetrical with respect to the central axis SS ′ . The angles AOD and BOC are 120 and 32 degrees, respectively. Although junctions A and D and junctions B and C ideally have the same area and tunnel resistance, small differences actu...

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“…Typically, Abrikosov lattice is the most stable configuration of voltices with repulsive force interaction to each other. However, when the system size is small, shape of superconductors, such as boundary condition, affects penetration and arrangement of vortices [1]. Similarly, topology of systems has a potential of affecting the superconducting properties.…”

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confidence: 99%

Cylinder vortex of superconductor in TaSe₃topological ring crystals

Kumagai

Matsuura

Ichimura

et al. 2009

J. Phys.: Conf. Ser.

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Abstract. Topology has many applications in modern condensed matter physics. We report that superconducting properties are changed by topology. We have measured the magnetic torque of the ring-shaped crystals of TaSe3 by using piezoresistive cantilevers in order to investigate the superconducting topological properties. We measured two ring samples. The outer radius of sample A was 37.9 µm and that of sample B was 24.5 µm. We found that the magnetic torque of the ring crystals changes periodically by increasing of the external magnetic field. The periodicity of sample A was 1.85 Gauss and that of sample B was 4.75 Gauss, respectively. We found that the period is proportional to the circumference of the ring crystal rather than the area enclosed by the outer circumference. In that case, it is natural that vortices in the ring crystal were placed along the circumference. From these results, we suggest that vortices exist as cylinder vortices in the rings at the results of topological effects of superconductive ring-shaped crystals, and this matter give a new experimental evidence of topological effect in superconductor. IntroductionWhat kind of effects on the superconducting state, such as a mixed state of type II superconductors, are caused by topology?At the mixed state vortices penetrate the superconductor when the applied magnetic field increases beyond H c1 . Typically, Abrikosov lattice is the most stable configuration of voltices with repulsive force interaction to each other. However, when the system size is small, shape of superconductors, such as boundary condition, affects penetration and arrangement of vortices [1]. Similarly, topology of systems has a potential of affecting the superconducting properties. For example, closed systems like ring crystals [2], vortices may not relocate to become stable like bulk superconductors, because they are trapped globally in the hole of the crystals. Furthermore, systems like Möbius ring crystals [3], there is the possibility that vortices cannot penetrate crystals. These speculations suggest that topology of systems plays an important role in physical properties.The purpose of this research is to investigate the effects of topology on superconducting properties. The ring-shaped crystals of quasi-one-dimensional superconductor TaSe 3 are suitable to investigate these topological effects, because it is expected that TaSe 3 causes topological effects for its filamentary structure. Besides that, a measurement without electrode is appropriate to investigate those effects, because this method conserves topology of systems. Therefore, we adopted magnetic torque measurement without electrode by using micro cantilevers [4]. As a result, we found a phenomenon that the magnetic torque of the ring crystals oscillates

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Vortex Entry and Nucleation of Antivortices in a Mesoscopic Superconducting Triangle

Cited by 139 publications

References 20 publications

Multivortex and giant vortex states near the expulsion and penetration fields in thin mesoscopic superconducting squares

Multivortex and giant vortex states near the expulsion and penetration fields in thin mesoscopic superconducting squares

Experimental Evidence for Giant Vortex States in a Mesoscopic Superconducting Disk

Cylinder vortex of superconductor in TaSe₃topological ring crystals

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Vortex Entry and Nucleation of Antivortices in a Mesoscopic Superconducting Triangle

Cited by 139 publications

References 20 publications

Multivortex and giant vortex states near the expulsion and penetration fields in thin mesoscopic superconducting squares

Multivortex and giant vortex states near the expulsion and penetration fields in thin mesoscopic superconducting squares

Experimental Evidence for Giant Vortex States in a Mesoscopic Superconducting Disk

Cylinder vortex of superconductor in TaSe3topological ring crystals

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Product

Resources

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Cylinder vortex of superconductor in TaSe₃topological ring crystals