Influence of structure of fine filament NbTi composite on its electromagnetic characteristics

Hlasnik, I.; Tsukamoto, O.; Fukui, Satoshi; Kumano, Tomoyuki; Polák, M.; Kokavec, Juraj; Majoroš, M.; Krempaský,; Suzuki, Eriko

doi:10.1109/77.233644

Cited by 11 publications

(1 citation statement)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In particular, the electron scattering mechanism 18 provides a detailed quasiclassical analysis for determining the pinning energy as a function of the concentration and electron scattering cross section of the pin, but it cannot be used for evaluating the pinning energy arising from the order-parameter variations due to the proximity effect. We think the details of the proximity coupling are crucial: In APC Nb-Ti composites, F p (H) reaches very high values at low fields and has a long tail at high fields when artificial Nb pins are thick, 17,21,22 but takes on a mid-field peak and a shape characteristic of core pinning when the pins are very thin. 23,24 Nb pins become strongly proximity coupled when thin, as demonstrated by the reduction of H c2 .…”

Section: Introductionmentioning

confidence: 98%

Flux-pinning mechanism of proximity-coupled planar defects in conventional superconductors: Evidence that magnetic pinning is the dominant pinning mechanism in niobium-titanium alloy

1996

View full text Add to dashboard Cite

We propose that a magnetic pinning mechanism is the dominant flux-pinning mechanism of proximitycoupled, planar defects when the field is parallel to the defect. We find compelling evidence that this pinning mechanism is responsible for the strong flux-pinning force exerted by ribbon-shaped ␣-Ti precipitates and artificial pins in Nb-Ti superconductors, instead of the core pinning mechanism as has been hitherto widely believed. Because the elementary pinning force f p (H) is nonmonotonic when it is optimum ͑i.e., when the defect thickness t and the proximity length N have comparable dimensions͒, the total pinning force F p (H) generally does not show temperature scaling. Characteristic changes in the magnitude and shape of F p (H) at constant T but at different t/ N ͑e.g., different Nb-Ti wire diameters͒ are also direct consequences of the pinning mechanism. The optimum flux-pinning state is a compromise between maximizing f p and getting the highest number density of pins. For a given defect composition this state is reached when tϳ N /3, while for varying defect composition the peak F p gets higher when N is made shorter. Artificial pinning center Nb-Ti wires having short N pins appear to be vital for obtaining high J c at high fields because only then is the elementary pinning force optimized at small pin thicknesses which permit a high number density of vortex-pin interactions and a large bulk pinning force. We find verification of our predictions in experimental F p (H,T,t) data obtained on special laboratory-scale artificial pinning-center Nb-Ti wires.

show abstract

Section: Introductionmentioning

confidence: 98%

Flux-pinning mechanism of proximity-coupled planar defects in conventional superconductors: Evidence that magnetic pinning is the dominant pinning mechanism in niobium-titanium alloy

1996

View full text Add to dashboard Cite

show abstract

Development of high‐J_c NbTi multifilamentary superconducting wire with Nb artificial pins for AC applications

Miura

Inoue

Matsumoto

et al. 1996

Electrical Engineering Japan

View full text Add to dashboard Cite

SUMMARYHigh critical current densities of 1.61 x 10" Aim' at 1 T, 6.1 x lo9 A/mZ at 3 T and 2.9 x lo9 A/m2 at 5 T were achieved by controlling the distribution of Nb artificial pins in NbTi multifilamentary superconducting wires for ac applications. The critical current densities attained are over two times higher than those of conventional ac superconducting wires. This increase can be attributed to the shift of the peak of pinning force density to higher magnetic field by optimizing the pinning parameters.The benefits of increasing critical current densities for ac applications are demonstrated. A 2.5 Ti100 kVA ac superconducting magnet was designed and made by using high J, wire with controlled distribution of Nb artificial pins. Compared with conventional ac superconducting magnets, the new magnet exhibits a drastic decrease in size as well as in ac losses.

show abstract

Self-field effect and current-voltage characteristics of a.c. superconductors

et al. 1994

View full text Add to dashboard Cite

Influence of structure of fine filament NbTi composite on its electromagnetic characteristics

Cited by 11 publications

References 4 publications

Flux-pinning mechanism of proximity-coupled planar defects in conventional superconductors: Evidence that magnetic pinning is the dominant pinning mechanism in niobium-titanium alloy

Flux-pinning mechanism of proximity-coupled planar defects in conventional superconductors: Evidence that magnetic pinning is the dominant pinning mechanism in niobium-titanium alloy

Development of high‐J_c NbTi multifilamentary superconducting wire with Nb artificial pins for AC applications

Self-field effect and current-voltage characteristics of a.c. superconductors

Contact Info

Product

Resources

About

Influence of structure of fine filament NbTi composite on its electromagnetic characteristics

Cited by 11 publications

References 4 publications

Flux-pinning mechanism of proximity-coupled planar defects in conventional superconductors: Evidence that magnetic pinning is the dominant pinning mechanism in niobium-titanium alloy

Flux-pinning mechanism of proximity-coupled planar defects in conventional superconductors: Evidence that magnetic pinning is the dominant pinning mechanism in niobium-titanium alloy

Development of high‐Jc NbTi multifilamentary superconducting wire with Nb artificial pins for AC applications

Self-field effect and current-voltage characteristics of a.c. superconductors

Contact Info

Product

Resources

About

Development of high‐J_c NbTi multifilamentary superconducting wire with Nb artificial pins for AC applications