The vortex lattice in conventional and high-Tc superconductors

Brandt, Ernst Helmut

doi:10.1590/s0103-97332002000400002

Cited by 6 publications

(6 citation statements)

References 21 publications

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“…For thin films, the correlated bundle radius is given by, R b = C 66 a/f √ n, where C 66 is the shear elastic modulus, a the mean vortex spacing, f the pinning force and n the areal density of pinning sites [20]. Noting that C 66 ∼ B/λ 2 [21], where B is the average flux density, and assuming that more pinning sites are coming into play at lower temperatures as the characteristic superconducting lengthscales reduce, then the pinning force and the density of pinning sites term, f √ n, can increase faster than 1/λ 2 . Thus, we can expect a decreasing bundle size as the temperature is decreased as observed.…”

Section: Resultsmentioning

confidence: 99%

Mapping the flux penetration profile in a 2G-HTS tape at the microscopic scale: deviations from a classical critical state model

Marchiori¹,

Bending²

2019

Supercond. Sci. Technol.

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Understanding vortex behaviour at microscopic scales is of extreme importance for the development of higher performance coated conductors with larger critical currents.Here, we study and map the critical state in a YBCO-based coated conductor at different temperatures using two distinct operation modes of scanning Hall microscopy. An analytical Bean critical state model for long superconducting strips is compared with our measurements and used to estimate the critical current density. We find several striking deviations from the model; pronounced flux front roughening is observed as the temperature is reduced below 83 K due to vortex-bundle formation when strong broadening of the flux front profile is also seen. In higher magnetic fields at the lower temperature of 65 K, fishtail-like magnetization peaks observed in local magnetization measurements are attributed to flux-locking due to an increase in the critical current density near the edges of the tape, which we tentatively link to vortex pinning matching effects. Our measurements provide valuable insights into the rich vortex phenomena present in coated conductor tapes at the microscopic scale.

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Section: Resultsmentioning

confidence: 99%

Mapping the flux penetration profile in a 2G-HTS tape at the microscopic scale: deviations from a classical critical state model

Marchiori¹,

Bending²

2019

Supercond. Sci. Technol.

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“…To quantitatively understand the magnetic field variation of ∆\/\, we now theoretically compute this quantity within harmonic approximation. The lattice vibration of the 2D vortex lattice is governed by two elastic moduli 25 : compression, C11, and shear C66. However C66 << C11, and therefore for small deformation the elastic energy of the VL is mainly controlled by C66.…”

Section: Ivc Theoretical Analysis Of Vortex Fluctuationmentioning

confidence: 99%

“…s t&, where A is area of rhombus unit cell and d is the thickness of film. In the London limit, the shear modulus of an isotropic superconductor for small magnetic field is given by 25 ,…”

Section: Ivc Theoretical Analysis Of Vortex Fluctuationmentioning

confidence: 99%

Evidence of zero-point fluctuation of vortices in a very weakly pinned a -MoGe thin film

et al. 2021

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In a Type II superconductor, the vortex core behaves like a normal metal. Consequently, the single-particle density of states in the vortex core of a conventional Type II superconductor remains either flat or (for very clean single crystals) exhibits a peak at zero bias due to the formation of Caroli-de Gennes-Matricon bound state inside the core. Here we report an unusual observation from scanning tunneling spectroscopy measurements in a weakly pinned thin film of the conventional s-wave superconductor a-MoGe, namely, that a soft gap in the local density of states continues to exist even at the center of the vortex core. We ascribe this observation to rapid fluctuation of vortices about their mean position that blurs the boundary between the gapless normal core and the gapped superconducting region outside. Analyzing the data as a function of magnetic field we show that the variation of fluctuation amplitude as a function of magnetic field is consistent with quantum zero-point motion of vortices.

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“…In case of a superconducting film on top of the AAO membrane, there is a striking similarity of the hexagonal vortex lattice with the hexagonal lattice of the AAO pores. Thus, one can expect matching effects as the distances in the vortex lattice are tunable on applying magnetic field perpendicular to the template surface according to

with

denoting the magnetic flux quantum, B the external magnetic field, and

the intervortex spacing [ 82 ].…”

Section: Realizationsmentioning

confidence: 99%

“…with Φ 0 denoting the magnetic flux quantum, B the external magnetic field, and a 0 the intervortex spacing [82].…”

Section: Templates To Introduce Defect Structures In Thin Filmsmentioning

confidence: 99%

Fabrication of Superconducting Nanowires Using the Template Method

Koblischka

Koblischka-Veneva

2021

Nanomaterials

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The fabrication and characterization of superconducting nanowires fabricated by the anodic aluminium oxide (AAO) template technique has been reviewed. This templating method was applied to conventional metallic superconductors, as well as to several high-temperature superconductors (HTSc). For filling the templates with superconducting material, several different techniques have been applied in the literature, including electrodeposition, sol-gel techniques, sputtering, and melting. Here, we discuss the various superconducting materials employed and the results obtained. The arising problems in the fabrication process and the difficulties concerning the separation of the nanowires from the templates are pointed out in detail. Furthermore, we compare HTSc nanowires prepared by AAO templating and electrospinning with each other, and give an outlook to further research directions.

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The vortex lattice in conventional and high-Tc superconductors

Cited by 6 publications

References 21 publications

Mapping the flux penetration profile in a 2G-HTS tape at the microscopic scale: deviations from a classical critical state model

Mapping the flux penetration profile in a 2G-HTS tape at the microscopic scale: deviations from a classical critical state model

Evidence of zero-point fluctuation of vortices in a very weakly pinned a -MoGe thin film

Fabrication of Superconducting Nanowires Using the Template Method

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