Flux flow in type II superconducting wires in longitudinal magnetic fields

Nicholson, James E.; Sikora, P. T.

doi:10.1007/bf00659074

Cited by 21 publications

(5 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, previous experiments on superconductors in parallel magnetic fields are still controversial. Namely, an electric field, and, correspondingly, dissipation appears along the field/current direction [4][5][6][7][8][9][10][11][12][13][14][15][16]. Moreover, the superconducting critical current appears to increase with the magnetic field [4][5][6][7][8]15].…”

Section: Sample Configurationmentioning

confidence: 99%

Parallel magnetic field suppresses dissipation in superconducting nanostrips

Wang

Glatz

Kimmel

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

The motion of Abrikosov vortices in type-II superconductors results in a finite resistance in the presence of an applied electric current. Elimination or reduction of the resistance via immobilization of vortices is the "holy grail" of superconductivity research. Common wisdom dictates that an increase in the magnetic field escalates the loss of energy since the number of vortices increases. Here we show that this is no longer true if the magnetic field and the current are applied parallel to each other. Our experimental studies on the resistive behavior of a superconducting Mo0.79Ge0.21 nanostrip reveal the emergence of a dissipative state with increasing magnetic field, followed by a pronounced resistance drop, signifying a re-entrance to the superconducting state. Large-scale simulations of the threedimensional time-dependent Ginzburg-Landau model indicate that the intermediate resistive state is due to an unwinding of twisted vortices. When the magnetic field increases, this instability is suppressed due to a better accommodation of the vortex lattice to the pinning configuration. Our findings show that magnetic field and geometrical confinement can suppress the dissipation induced by vortex motion and thus radically improve the performance of superconducting materials.superconducting vortices parallel magnetic field Time-dependent GinzburgLandau simulation Abbreviations: TDGL simulation:Time-Dependent Ginzburg-Landau simulation ortex dynamics determines the electromagnetic responses of almost all practically important superconductors. Abrikosov vortices are created by the magnetic field penetrating a type-II superconductor, each carrying a single flux quantum surrounded by circulating supercurrents [1]. Understanding the electromagnetic properties of superconductors in applied magnetic fields is crucial for the majority of superconducting applications. If an electric current, I, is applied to the superconductor with a magnetic induction B, the associated Lorentz force FL = I B can induce motion of the vortices if it is greater than the vortex pinning force due to defects.[2] The vortex motion in turn leads to dissipation and breakdown of the zero-resistance state. Another practically important situation is when the magnetic field and the current are parallel, for example in force-free superconductnomena, [13,[17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] including flux cutting [19,30,33,34], helical normal/superconducting domains, [35,36] and helical vortex flow. [13,31] However, the vortex behavior responsible for the observed dissipation in parallel magnetic field is still under debate [14,28,30,31].All the above mentioned experiments and theories focus on macroscopic samples with dimensions much larger than the superconducting coherence length. On the other hand, when the dimensions of the sample become comparable to the superconducting coherence length, the subtle interplay of vortex lattice confinement and pinning may lead to new behavior. Here, we investigate this non-trivial problem...

show abstract

Section: Sample Configurationmentioning

confidence: 99%

Parallel magnetic field suppresses dissipation in superconducting nanostrips

Wang

Glatz

Kimmel

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…The concept of flux line cutting was introduced to account for the observation of a flux-flow voltage along a straight wire of a type II superconductor carrying a steady current I > I c in a static longitudinal magnetic field H [1]. When H = 0, the azimuthal flux lines generated at the surface of the wire by the longitudinal current I close on themselves and form vortex rings.…”

Section: Introductionmentioning

confidence: 99%

Flux line cutting and cross-flow in a high-T_csuperconducting YBCO tube

LeBlanc

Çelebi

2003

Supercond. Sci. Technol.

View full text Add to dashboard Cite

We present strong evidence observed in a YBCO superconducting tube that helical flux lines can concurrently enter and leave across the inner surface of the wall of a hollow cylinder of sintered high-Tc superconductors at 77 K, and hence cut and traverse each other. The evidence for flux line cutting and cross-flow is examined in the perspective of basic concepts. The traffic of the flux lines is also described mathematically. The penetration fields across the wall and into the grains of the sintered ceramic tube are seen to correlate with salient features (peaks and valleys) of the flux line cutting and cross-flow phenomena. This enables us to claim that we are witnessing flux line cutting and cross-flow in the weak links as well as in the interior of the grains in the YBCO tube. The Clem/Perez-Gonzalez phenomenological theory is exploited in a simplified framework to describe the crucial features of the data semi-quantitatively. This analysis confirms the above conclusions and provides estimates of jc||m and jc||g, the critical current densities for intergranular and intragranular flux line cutting and their dependence on the magnetic flux density.

show abstract

“…2'3 Flux-flow resistance is observed also in long cylinders carrying a current parallel to an applied axial magnetic field. [4][5][6][7][8][9][10][11][12][13][14][15] In spite of considerable effort, 3'16-24 a satisfactory explanation of flux-flow resistance in longitudinal geometry has not yet been given. Any microscopic mechanism for voltage generation by FLs moving at a velocity v inevitably leads to "force-free 33 configurations" in which the FLs are parallel to the local current density j everywhere.…”

Section: Introductionmentioning

confidence: 99%

Longitudinal critical current in type II superconductors. I. Helical vortex instability in the bulk

Brandt

1981

J Low Temp Phys

View full text Add to dashboard Cite

The vortex lattice in type H superconductors is unstable against the growth of helical perturbations if the current along the vortices exceeds a critical value. The longitudinal critical current, the pitch, and the spatially varying amplitude of the elliptically polarized helices are calculated from the London theory at the onset of instability in planar current distributions far from the surface. For weak pinning (atA 2 << C66) the wavelength and width of the mode extend over 1/4 the entire specimen, and the critical current is 2H(c66/c11) . For moderate pinning (c66 << aLA 2 << C11) the wavelength and width are close to Campbell's pinning length (c11/az)1/2, and the critical current times its mean density is 2 ~/2 . • 2 >> .... 2H (aL/C11) . For strong pmnmg (OLLI~ Cll ) hehcal mstabthty occurs at pin-free vortex sections, the helix wavelength is 2.2d, and the critical current density is 0.47Hd/A 2 (H, d, cll and C66 , and aL are the magnetic field, spacing, elastic moduli, and pinning parameter of the vortex lattice, and ~ is the magnetic penetration depth).

show abstract

Flux flow in type II superconducting wires in longitudinal magnetic fields

Cited by 21 publications

References 15 publications

Parallel magnetic field suppresses dissipation in superconducting nanostrips

Parallel magnetic field suppresses dissipation in superconducting nanostrips

Flux line cutting and cross-flow in a high-T_csuperconducting YBCO tube

Longitudinal critical current in type II superconductors. I. Helical vortex instability in the bulk

Contact Info

Product

Resources

About

Flux flow in type II superconducting wires in longitudinal magnetic fields

Cited by 21 publications

References 15 publications

Parallel magnetic field suppresses dissipation in superconducting nanostrips

Parallel magnetic field suppresses dissipation in superconducting nanostrips

Flux line cutting and cross-flow in a high-Tcsuperconducting YBCO tube

Longitudinal critical current in type II superconductors. I. Helical vortex instability in the bulk

Contact Info

Product

Resources

About

Flux line cutting and cross-flow in a high-T_csuperconducting YBCO tube