Influence of sample geometry on vortex matter in superconducting microstructures

Morelle, Mathieu; Bekaert, Joost; Moshchalkov, Victor

doi:10.1103/physrevb.70.094503

Cited by 38 publications

(23 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In Ref. 21 peaks were found at L = 4 in a square and one at L = 3 in a triangle. Now, we will study the temperature dependence of this enhanced stability at L = 4 in a square sample with W =10 in more detail.…”

Section: Stability Of the Different Vortex Statesmentioning

confidence: 99%

“…Experimentally, Morelle et al 21 performed Hall magnetometry measurements on a Al square and triangle and discussed the stability of the different vortex patterns at two temperatures close to T c . But no systematic study of the temperature dependence of the vortex state stability was presented.…”

Section: Stability Of the Different Vortex Statesmentioning

confidence: 99%

“…14 In addition, it became clear that the stability of the different vortex states strongly depends on the sample shape. Experimentally, both resistivity measurements 7,20 and Hall magnetometry 21 have been performed on mesoscopic superconducting squares and triangles. H-T phase diagrams were constructed and the stability of the different vortex states were studied.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

et al. 2006

View full text Add to dashboard Cite

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.

show abstract

Section: Stability Of the Different Vortex Statesmentioning

confidence: 99%

Section: Stability Of the Different Vortex Statesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

et al. 2006

View full text Add to dashboard Cite

show abstract

“…On the other hand, little work has been done on the manipulation and detection of vortex motion in mesoscopic superconductors, which are more relevant for technological applications than planar films. Static few vortex states in mesoscopic superconductors have been studied previously both theoretically [12][13][14][15][16] and experimentally [17][18][19][20][21][22][23][24][25], with an impressive accumulation of detailed understanding. Studies of vortex motion have also been carried out [26][27][28][29][30] and have led to interesting findings such as vortex-crossing-induced magnetoresistance oscillations [27,29,30] with an amplitude much larger than that of the traditional Little-Parks effect [31].…”

mentioning

confidence: 99%

Vortex crossing and trapping in doubly connected mesoscopic loops of a single-crystal type-II superconductor

Mills

Shen

et al. 2015

Phys. Rev. B

View full text Add to dashboard Cite

Numerical calculations on a mesoscopic ring of a type II superconductor in the London limit suggest that an Abrikosov vortex can be trapped in such a structure above a critical magnetic field and generate a phase shift in the magnetoresistance oscillations. We prepared submicron-sized superconducting loops of single-crystal, type II superconductor NbSe2 and measured magnetoresistance oscillations resulting from vortices crossing the loops. The free energy barrier for vortex crossing determines the crossing rate and is periodically modulated by the external magnetic flux threading the loop. We demonstrated experimentally that the crossing of vortices can be directed at a pair of constrictions in the loop, leading to more pronounced magnetoresistance oscillations than those in a uniform ring. The vortex trapping in both a simple ring and a ring featuring two constrictions was found to result in a phase shift in the magnetoresistance oscillations as predicted in the numerical calculations. The controlled crossing and trapping of vortices demonstrated in our NbSe2 devices provide a starting point for the manipulation of individual Abrikosov vortices, which is useful for future technologies.

show abstract

“…Moreover, a different approach is needed to explore the condensate in the nondissipative (zero voltage) state. In order to tackle these issues a second set of experiments probes the magnetic field profiles, generated by the superconducting currents, by using magnetic field sensitive probes (e.g., Hall probe [7,8], scanning Hall probe microscopy [9], Bitter decoration [10], and scanning SQUID microscopy [11]). These techniques indeed visualized the symmetry-induced vortex configurations in superconducting nanostructures within the low confinement regime (i.e., nanostructure size ∼λ ξ ).…”

mentioning

confidence: 99%

Direct observation of condensate and vortex confinement in nanostructured superconductors

et al. 2016

View full text Add to dashboard Cite

In this work we report a scanning tunneling microscopy investigation of lithographically defined superconducting nanosquares. The obtained spectroscopic maps reveal the spatial evolution of both the superconducting condensate and the screening currents as a function of the applied magnetic field. The symmetry of the nanostructure is imposed on the condensate and it controls the distribution of the vortices inside the nanosquare. Our local study allows exploring the impact of small structural defects, omnipresent in these kind of structures, on both the supercurrent and vortex distribution. As a result, direct experimental evidence of vortex pinning and current crowding at the nanoscale has been obtained. DOI: 10.1103/PhysRevB.93.054514 Confinement effects play an important role in different physical phenomena especially in quantum systems like Bose-Einstein condensates, superconductors, and superfluids. For example, the ability to structure superconducting devices at length scales comparable to the characteristic sizes (penetration dept λ and coherence length ξ ) of the condensate revealed a vast world of possibilities to explore quantum phenomena (e.g., creation of artificial atoms [1], induction of quantum phase slip lines [2], confinement effects [3], to name a few). In the latter example, theoretical modeling of these systems solving the Ginzburg-Landau (G-L) [4,5] or Bogoliubov-deGennes (B-dG) [6] equations for single and/or multiband mesoscopic superconductors has been done. All these simulations unveil the importance of confinement in mesoscopic superconducting systems. For example, the symmetry of the nanostructure will compete with the vortex-vortex interaction resulting in different vortex configurations compared to the triangular Abrikosov lattice, found in bulk superconductors [3][4][5][6].These intriguing effects were experimentally investigated, using low temperature transport measurements, by probing the influence of nanostructuring on the superconductor/normal phase boundary [3]. Although these measurements proved the importance of size and shape they do not give sufficient local information about the spatial distribution of the superconducting condensate. Moreover, a different approach is needed to explore the condensate in the nondissipative (zero voltage) state. In order to tackle these issues a second set of experiments probes the magnetic field profiles, generated by the superconducting currents, by using magnetic field sensitive probes (e.g., Hall probe [7,8], scanning Hall probe microscopy [9], Bitter decoration [10], and scanning SQUID microscopy [11]). These techniques indeed visualized the symmetry-induced vortex configurations in superconducting nanostructures within the low confinement regime (i.e., nanostructure size ∼λ ξ ). The observed configurations are the results of the imposed boundary conditions and the repulsive magnetic interactions between vortices. In the strong confinement regime (i.e., nanostructure size ∼ξ λ), the distribution of the superconducting condensate is gov...

show abstract

Influence of sample geometry on vortex matter in superconducting microstructures

Cited by 38 publications

References 34 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

Vortex crossing and trapping in doubly connected mesoscopic loops of a single-crystal type-II superconductor

Direct observation of condensate and vortex confinement in nanostructured superconductors

Contact Info

Product

Resources

About