The unified strain and temperature scaling law for the pinning force density of bronze-route Nb3Sn wires in high magnetic fields

Cheggour, Najib; Hampshire, D.P.

doi:10.1016/s0011-2275(02)00038-3

Cited by 34 publications

(60 citation statements)

References 67 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…4͑b͔͒. This behavior has been also observed by other groups in MgB 2 , 13,15 Nb 3 Sn, 26,27 and NbTi ͑Ref. 5͒ and, therefore, may not be considered as material specific, but caused by a distribution of parameters determin- ing F p combined with the particular choice of B * .…”

Section: Flux Pinning Curvessupporting

confidence: 58%

Flux pinning force in bulkMgB2with variable grain size

et al. 2007

View full text Add to dashboard Cite

We report temperature and magnetic-field dependence of flux pinning force in bulk MgB 2 with variable grain size. The samples are prepared by advanced methods, allowing minimizing effects of porosity, impurities, and inclusions of secondary phases. The effects of grain connectivity, flux-creep phenomena, and grain size on critical current density and flux pinning curves are analyzed. We have compared the field dependence of the pinning force for a range of samples with the predictions of theoretical models accounting for the effect of the grain size. There is qualitative agreement between grain-boundary pinning mechanism proposed by Hampshire and Jones ͓J. Phys. C 21, 419 ͑1987͔͒ and the experimentally observed grain-size dependence of pinning force in bulk MgB 2 .

show abstract

Section: Flux Pinning Curvessupporting

confidence: 58%

Flux pinning force in bulkMgB2with variable grain size

et al. 2007

View full text Add to dashboard Cite

show abstract

“…The new apparatus allows us to measure the strand in compression and tension to cover a range of applied strain typically from −1 % to +1 %, based on Cheggour's original design [18,19] ("Durham probe" using a "Walter's spring" technique [20]). The variable temperature design utilizes our high-rate helium gas flow and gas temperature pre-regulation approach that was developed at NIST.…”

Section: New Variable Strain/temperature/magnetic-field Apparatusmentioning

confidence: 99%

Final Technical Report

Goodrich¹

2011

View full text Add to dashboard Cite

“…20,34 A third characteristic of wires is the presence of residual strain. Macroscopically, the strain dependence on 0 H K ͑T͒ is well understood in terms of axial strain, [35][36][37] or deviatoric strain, 38,39 but its influence on the complete H-T phase transition is still uncertain. 40 The large Cu matrix enforces a compressive axial strain on the A15 layers due to the larger contraction of the Cu with respect to the A15.…”

Section: Introductionmentioning

confidence: 99%

“…2 Expressions for the H-T phase transition, derived directly from the BCS theory, are readily available in the literature, [44][45][46][47][48][49][50][51][52] and have been applied with success to welldefined laboratory specimens, 1,17,53,54 but most of the H-T data on wires are empirically described. 36,37,41 This leads to continuing discussions in the literature, partly resulting from the use of extrapolated values of 0 H c2 ͑0͒ without taking into account the inhomogeneous nature of the conductors. Although such empirical relations in principle yield sufficient accuracy for the scaling of J c , 42 large discrepancies occur between the fitted values for 0 H K ͑0͒ and T c ͑0͒ and actual measurements.…”

Section: Introductionmentioning

confidence: 99%

The upper critical field of filamentary Nb3Sn conductors

Godeke

Jewell

Fischer

et al. 2005

Journal of Applied Physics

101

128

View full text Add to dashboard Cite

We have examined the upper critical field of a large and representative set of present multifilamentary Nb 3 Sn wires and one bulk sample over a temperature range from 1.4 K up to the zero-field critical temperature. Since all present wires use a solid-state diffusion reaction to form the A15 layers, inhomogeneities with respect to Sn content are inevitable, in contrast to some previously studied homogeneous samples. Our study emphasizes the effects that these inevitable inhomogeneities have on the field-temperature phase boundary. The property inhomogeneities are extracted from field-dependent resistive transitions which we find broaden with increasing inhomogeneity. The upper 90%-99% of the transitions clearly separates alloyed and binary wires but a pure, Cu-free binary bulk sample also exhibits a zero-temperature critical field that is comparable to the ternary wires. The highest 0 H c2 detected in the ternary wires are remarkably constant: The highest zero-temperature upper critical fields and zero-field critical temperatures fall within 29.5± 0.3 and 17.8± 0.3 K, respectively, independent of the wire layout. The complete field-temperature phase boundary can be described very well with the relatively simple Maki-DeGennes model using a two-parameter fit, independent of composition, strain state, sample layout, or applied critical state criterion.

show abstract

The unified strain and temperature scaling law for the pinning force density of bronze-route Nb3Sn wires in high magnetic fields

Cited by 34 publications

References 67 publications

Flux pinning force in bulkMgB2with variable grain size

Flux pinning force in bulkMgB2with variable grain size

Final Technical Report

The upper critical field of filamentary Nb3Sn conductors

Contact Info

Product

Resources

About