Irreversibility line and granularity in Chevrel phase superconducting wires

Cheggour, Najib; Decroux, M.; Fischer, Ø.; Hampshire, D.P.

doi:10.1063/1.368358

Cited by 15 publications

(3 citation statements)

References 16 publications

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“…Experimental values of n for low-temperature type-II superconductors such as NbTi [75], V 3 Ga [92], Nb 3 Al [30], Nb 3 Sn [35] and PbMo 6 S 8 [66,67,93] are in the range 2 n 3. Hence, the values of n obtained from constraining B C2 at 5%ρ N are consistent with both the theoretical [62] and experimental values in the literature.…”

Section: Discussionmentioning

confidence: 99%

The strain and temperature scaling law for the critical current density of a jelly-roll Nb3Al strand in high magnetic fields

Keys

Koizumi

Hampshire

2002

Supercond. Sci. Technol.

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The engineering critical current density (J E ) and the index of transition, N (where E = αJ N ), of a Nb 3 Al multifilamentary strand, mass-produced as a part of the Fusion programme, have been characterized as a function of field (B), temperature (T ) and strain (ε) in the ranges B 15 T, 4.2 K T 16 K and −1.79% ε +0.67%. Complementary resistivity measurements were taken to determine the upper critical field (B C2 (T , ε)) and the critical temperature (T C (ε)) directly. The upper critical field defined at 5%ρ N , 50%ρ N or 95%ρ N , is described by the empirical relation B ρ N C2 (T , ε) = B ρ N C2 (0, ε) 1 − T T ρ N C (ε) ν . The upper critical field at zero 0953-2048/02/070991+20$30.00 © 2002 IOP Publishing Ltd Printed in the UK b 1 2where the Ginzburg-Landau (GL) parameter κ is given by the relation, γ is the Sommerfeld constant and t = T/T C (ε). At an applied field equal to the upper critical field found from fitting the Kramer dependence (i.e. at B C2 (T , ε)), the critical current is non-zero and we suggest that the current flow is percolative. The functional form of F P implies that in high fields the grain boundary pinning does not limit J E , this is consistent with J E -microstructure correlations in other superconducting materials.

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Section: Discussionmentioning

confidence: 99%

The strain and temperature scaling law for the critical current density of a jelly-roll Nb3Al strand in high magnetic fields

Keys

Koizumi

Hampshire

2002

Supercond. Sci. Technol.

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“…Hence, although the physical processes associated with these two equations are completely different, it is clear that fitting the data app The J c data for YBCO (Superpower 'Turbo' double layer tape), Bi-2212 (OST 2212 wire with 100 bar over-pressure) and Bi-2223 (Sumitomo Electric Industries 'DI' BSCCO tape) are taken from [28]. J c data for Nb (thin film with artificial nanoscale pores) [12] (measured at 5 K), Nb-47Ti ( [133], 37% superconductor cross-section area (SCSA)), Nb 3 Sn (Internal Sn RRP (IT), 12% SCSA [96] and High Sn Bronze-route (B), 11% SCSA [97]), Nb 3 Al (jelly-roll strands, 32% SCSA) [116], (NbTa) 3 Sn (11% SCSA) [117], PbMo 6 S 8 [134], MgB 2 (AIMI 18 Filament (39% Filament CS)) [94], FeSe 0.5 Te 0.5 (thin film IBAD substrates) [95] and Ba(FeCo) 2 As 2 (thin film on CaF 2 substrates) [91] are also included. Closed and open symbols are used for anisotropic materials and signify that the magnetic field is parallel and perpendicular to the ab-plane respectively.…”

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confidence: 99%

How resistive must grain boundaries in polycrystalline superconductors be, to limitJ_c?

Wang

Raine

Hampshire

2017

Supercond. Sci. Technol.

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Although we can use misorientation angle to distinguish the grain boundaries that can carry high critical current density in high temperature superconductors (HTS) from those that cannot, there is no established normal state property equivalent. In this paper, we explore the superconducting and normal state properties of the grains and grain boundaries of polycrystalline YBa2Cu3O7−x (YBCO) using complementary magnetisation and transport measurements, and calculate how resistive grain boundaries must be to limit in polycrystalline superconductors. The average resistivity of the grain boundaries, in our micro- and nanocrystalline YBCO are 0.12 Ωm and 8.2 Ωm, values which are much higher than that of the grains and leads to huge values of 2 × 103 and 1.6 × 105 respectively. We find that the grain boundaries in our polycrystalline YBCO are sufficiently resistive that we can expect the transport to be several tens of orders of magnitude below the potential current density of the grains in our YBCO samples, as is found experimentally. Calculations presented show that increasing values by ∼2 orders of magnitude in high fields is still possible in all state-of-the-art technological high-field superconductors. We conclude: grain boundary engineering is unlikely to improve sufficiently in randomly aligned polycrystalline YBCO, to make it technologically useful for high-field applications; in low temperature superconducting intermetallics, such as Nb3Sn, large increases in may be achieved by completely removing the grain boundaries from these materials and, as is the case for thin films of Nb, Ba(FeCo)2As2 and HTS materials, by incorporating additional artificial pinning.

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“…In general, any realistic mathematical framework is more complex at high temperatures than at low temperatures and a distribution in 𝑇 " and 𝐵 "V (𝑇) will also play a role. Scaling in the E-J characteristics has been observed in both low temperature [110] and high temperature superconductors [109].…”

Section: G2342 the Functional Form Of The E-j Characteristicmentioning

confidence: 99%

Characterisation of the Transport Critical Current Density for Conductor Applications

Raine¹,

Keys²,

Hampshire³

2022

Handbook of Superconductivity

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Irreversibility line and granularity in Chevrel phase superconducting wires

Abstract: Articles you may be interested inPhase transformation and superconducting properties of MgB 2 using ball-milled low purity boron

Cited by 15 publications

References 16 publications

The strain and temperature scaling law for the critical current density of a jelly-roll Nb3Al strand in high magnetic fields

The strain and temperature scaling law for the critical current density of a jelly-roll Nb3Al strand in high magnetic fields

How resistive must grain boundaries in polycrystalline superconductors be, to limitJ_c?

Characterisation of the Transport Critical Current Density for Conductor Applications

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Irreversibility line and granularity in Chevrel phase superconducting wires

Abstract: Articles you may be interested inPhase transformation and superconducting properties of MgB 2 using ball-milled low purity boron

Cited by 15 publications

References 16 publications

The strain and temperature scaling law for the critical current density of a jelly-roll Nb3Al strand in high magnetic fields

The strain and temperature scaling law for the critical current density of a jelly-roll Nb3Al strand in high magnetic fields

How resistive must grain boundaries in polycrystalline superconductors be, to limitJc?

Characterisation of the Transport Critical Current Density for Conductor Applications

Contact Info

Product

Resources

About

How resistive must grain boundaries in polycrystalline superconductors be, to limitJ_c?