Interstitial flux phases in a superconducting niobium film with a square lattice of artificial pinning centers

Metlushko, V.; Welp, U.; Crabtree, G. W.; Osgood, Richard M.; Bader, S. D.; DeLong, L. E.; Zhao, Ziran; Brueck, S. R. J.; Ilić, B.; Chung, Kee‐Choo; Hesketh, Peter J.

doi:10.1103/physrevb.60.r12585

Cited by 131 publications

(97 citation statements)

References 24 publications

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“…It is now well established that these artificial pinning centers (i) hold great potential for enhancing the critical parameters of the sample and (ii) give rise to different kinds of vortex behavior that is not observed in the presence of random pinning. In this respect, arrays of microholes (antidots) 1,2,3,4,5,6,7,8,9,10,11,12 and submicron magnetic dots, 13,14,15 have been studied, as their presence in the SC film strongly modifies the vortex structure compared to the one in non-patterned films. 16,17 Direct imaging experiments, 1 magnetization and transport measurements, 2,3,4,5 and theoretical simulations 18,19,20,21,22 of vortex structures in samples with periodic pinning centers have shown that the vortices form highly ordered configurations at integer H n = nΦ 0 /S and at some fractional H p/q = p q Φ 0 /S (n,p,q being integers) matching fields, where Φ 0 = hc/2e = 2.07 · 10 −7 Gcm 2 is the flux quantum, and S is the area of the primitive cell of the artificial lattice.…”

Section: Introductionmentioning

confidence: 99%

Vortex configurations and critical parameters in superconducting thin films containing antidot arrays: Nonlinear Ginzburg-Landau theory

Berdiyorov

Miloševıć²,

Peeters³

2006

Phys. Rev. B

110

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Using the non-linear Ginzburg-Landau (GL) theory, we obtain the possible vortex configurations in superconducting thin films containing a square lattice of antidots. The equilibrium structural phase diagram is constructed which gives the different ground-state vortex configurations as function of the size and periodicity of the antidots for a given effective GL parameter κ * . Giant-vortex states, combination of giant-and multi-vortex states, as well as symmetry imposed vortex-antivortex states are found to be the ground state for particular geometrical parameters of the sample. The antidot occupation number no is calculated as a function of related parameters and comparison with existing expressions for the saturation number ns and with experimental results is given. For a small radius of antidots a triangular vortex lattice is obtained, where some of the vortices are pinned by the antidots and some of them are located between them. Transition between the square pinned and triangular vortex lattices is given for different values of the applied field. The enhanced critical current at integer and rational matching fields is found, where the level of enhancement at given magnetic field directly depends on the vortex-occupation number of the antidots. For certain parameters of the antidot lattice and/or temperature the critical current is found to be larger for higher magnetic fields. Superconducting/normal H − T phase boundary exhibits different regimes as antidots are made larger, and we transit from a plain superconducting film to a thin-wire superconducting network. Presented results are in good agreement with available experiments and suggest possible new experiments.

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Section: Introductionmentioning

confidence: 99%

Vortex configurations and critical parameters in superconducting thin films containing antidot arrays: Nonlinear Ginzburg-Landau theory

Berdiyorov

Miloševıć²,

Peeters³

2006

Phys. Rev. B

110

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“…Superconducting films with a lattice of artificial pinning centers (APCs) have been investigated for several years 1,2,3,4,5 . It is found that the vortex lattice is highly ordered at certain matching fields, H n , where the number of flux lines equals an integer multiple n of the number of APCs.…”

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confidence: 99%

“…Technical details of the patterning procedure can be found in Ref. [3]. Figure 2 shows the differential resistance of the Nb film as a function of magnetic field normal to the film with different dc bias currents (I dc ) through the sample.…”

mentioning

confidence: 99%

Pinning phenomena in a superconducting film with a square lattice of artificial pinning centers

Jiang

Dikin

Chandrasekhar

et al. 2004

Applied Physics Letters

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We study the transport properties of a superconducting Nb film with a square lattice of artificial pinning centers (APCs) as a function of dc current, at a temperature close to the superconducting transition temperature of the film. We find that, at low dc currents, the differential resistance of the film shows the standard matching field anomaly, that is, the differential resistance has a local minimum at magnetic fields corresponding to an integer number of flux lines per APC. However, at higher dc currents, the differential resistance at each matching field turns to a local maximum, which is exactly opposite to the low current behavior. This novel effect might indicate that the flux lines in the APC system change their flow mode as the dc current is increased.

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“…For that reason, much attention has been given in the past to hampering vortex motion by introducing arrays of artificial pinning centers in superconductors, nanoengineered in size and geometry for optimal vortex pinning and enhancement of maximal sustainable magnetic field and electric current in the superconducting state [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] . Pinning is also of importance in type-I superconductors, for example in defining the structure of the intermediate state (IS) 18,19 , which is a very rich study object and has received a revival of interest in recent years [20][21][22][23][24][25][26][27][28][29][30][31][32] .…”

mentioning

confidence: 99%

Microfluidic manipulation of magnetic flux domains in type-I superconductors: droplet formation, fusion and fission

Berdiyorov

Miloševıć

Hernández-Nieves

et al. 2017

Sci Rep

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The magnetic flux domains in the intermediate state of type-I superconductors are known to resemble fluid droplets, and their dynamics in applied electric current is often cartooned as a "dripping faucet". Here we show, using the time-depended Ginzburg-Landau simulations, that microfluidic principles hold also for the determination of the size of the magnetic flux-droplet as a function of the applied current, as well as for the merger or splitting of those droplets in the presence of the nanoengineered obstacles for droplet motion. Differently from fluids, the flux-droplets in superconductors are quantized and dissipative objects, and their pinning/depinning, nucleation, and splitting occur in a discretized form, all traceable in the voltage measured across the sample. At larger applied currents, we demonstrate how obstacles can cause branching of laminar flux streams or their transformation into mobile droplets, as readily observed in experiments.Moving superconducting vortices are known to be the main source for energy dissipation in current-carrying type-II superconductors, limiting their large scale energy-related applications. For that reason, much attention has been given in the past to hampering vortex motion by introducing arrays of artificial pinning centers in superconductors, nanoengineered in size and geometry for optimal vortex pinning and enhancement of maximal sustainable magnetic field and electric current in the superconducting state [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] . Pinning is also of importance in type-I superconductors, for example in defining the structure of the intermediate state (IS) 18,19 , which is a very rich study object and has received a revival of interest in recent years [20][21][22][23][24][25][26][27][28][29][30][31][32] . Contrary to type-II superconductors, the competition between the interface energy (that favors the formation of large normal domains) and the magnetic energy (that tends to form small normal domains) results in the formation of different spatially modulated IS structures in type-I superconductors 23,30 . There, flux tubes and lamellae are the most encountered shapes [18][19][20] , formation of which strongly depends on the size and shape of the samples [22][23][24] , as well as on the magnetic history of the system 18,19 .Unlike Abrikosov vortices in type-II superconductors, each carrying a single flux quantum Φ 0 = hc/2e 33,34 , flux droplets in type-I superconductors may contain hundreds of flux quanta and are considered as building blocks for the IS flux patterns 35,36 . When driven by applied current, these flux structures can undergo different dynamic phases, where the motion of droplets can be periodic (with single or multiple periods) as well as chaotic 21 . Recent numerical simulations revealed that type-I flux droplets are always decomposed into singly-quantized fluxoids during dynamic interactions, reaffirming that one flux quantum is the smallest and fundamental building block of the IS in type-I superconductors 25 . Stat...

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Interstitial flux phases in a superconducting niobium film with a square lattice of artificial pinning centers

Cited by 131 publications

References 24 publications

Vortex configurations and critical parameters in superconducting thin films containing antidot arrays: Nonlinear Ginzburg-Landau theory

Vortex configurations and critical parameters in superconducting thin films containing antidot arrays: Nonlinear Ginzburg-Landau theory

Pinning phenomena in a superconducting film with a square lattice of artificial pinning centers

Microfluidic manipulation of magnetic flux domains in type-I superconductors: droplet formation, fusion and fission

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