Normal and superconducting properties of niobium rich niobium-tantalum alloys

Ohtsuka, Toshiya; Kimura, Y.

doi:10.1016/0031-8914(71)90302-8

Cited by 18 publications

(7 citation statements)

References 16 publications

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“…The upper critical field (H C2 ) is determined primarily as the crossover field from the diamagnetic to paramagnetic state, and the value of H C2 estimated in this procedure is around 5 kOe for all the samples (see figure 7). However, this value of H C2 is considerable larger than the H C2 (0) value for pure niobium reported in the literature [13,14]. On a closer inspection, a distinct knee is observed at around 4.1 kOe in the field increasing leg of the isothermal M-H curve presented in figure 7.…”

Section: Resultsmentioning

confidence: 49%

“…The superconducting transition temperature T C of pure niobium was reported to be decreased from ≈9.2 to ≈8.9 K in 0.87 at.% Ta-doped niobium. In contrast, Ohtsuka and Kimura [14] reported T C of 9.02 K in 2 at.% Ta-doped niobium. As mentioned above, the critical field at which magnetic flux-lines start penetrating the type-II superconductor is an important factor in the performance degradation in the SCRF cavity.…”

Section: Introductionmentioning

confidence: 87%

“…The lower critical field of niobium was reported to decrease rather slowly with the increase in the amount of Ta-impurity [13]. It is to be noted, however, that in all these studies [13,14] the compositions of the Nb-Ta alloys are nominal compositions. The difference in T C of Nb-Ta alloys between the two reports [13,14] is small, but this difference in transition temperature is significant enough to influence the performance in a SCRF cavity [11].…”

Section: Introductionmentioning

confidence: 90%

“…It is to be noted, however, that in all these studies [13,14] the compositions of the Nb-Ta alloys are nominal compositions. The difference in T C of Nb-Ta alloys between the two reports [13,14] is small, but this difference in transition temperature is significant enough to influence the performance in a SCRF cavity [11]. Hence, in the context of SCRF-cavity materials it is important to investigate the superconducting properties of technical-niobium materials after proper quantification of their impurity contents.…”

Section: Introductionmentioning

confidence: 99%

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A study on the effect of tantalum-impurity content on the superconducting properties of niobium materials used for making superconducting radio frequency cavities

Roy

Chandra

Chattopadhyay

et al. 2012

Supercond. Sci. Technol.

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Niobium materials in highly pure form are used in the fabrication of superconducting radio frequency cavities. We present here a study of the superconducting properties of such niobium materials that have been used in the fabrication of high accelerating gradient superconducting radio frequency cavities after determining their tantalum-impurity contents using a synchrotron-based x-ray fluorescence spectroscopy technique. Our results show that there is a small change in superconducting parameters such as T C , H C1 and H C2 when the tantalum-impurity content varies from ≈150 to ≈1300 ppm. In contrast, a buffered chemical polishing of the same niobium samples changes all these superconducting parameters more significantly. The implications of these results on the performance of niobium superconducting radio frequency cavities are discussed.

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Section: Resultsmentioning

confidence: 49%

Section: Introductionmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A study on the effect of tantalum-impurity content on the superconducting properties of niobium materials used for making superconducting radio frequency cavities

Roy

Chandra

Chattopadhyay

et al. 2012

Supercond. Sci. Technol.

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“…In the limit of small layer thickness we do observe the dependence predicted by Eq. (2), with zero slope, dH, z(8)ldT, at parallel field (shown for 55-34 in Fig. 7 Solid lines are guides to the eye.…”

Section: Upper Critical Fieldsmentioning

confidence: 99%

Upper critical fields of periodic and quasiperiodic Nb-Ta superlattices

et al. 1988

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Upper critical fields have been studied for two series of Nb-Ta superlattices grown by molecularbeam epitaxy with both periodic and quasiperiodic (Fibonacci sequence) layering. X-ray results are presented to characterize the nature and quality of the layering. Positive curvature in the perpendicular upper critical field (H, »), pronounced negative curvature near T, in the parallel upper critical field (H, 2~~), and dimensional crossover are observed in both types of samples. For quasiperiodic samples two upturns are observed in H, 2~~w ith decreasing temperature. These are shown to be associated with dimensional crossover occurring twice as the superconducting coherence length in the growth direction, g"samples the two length scales, 2d~b and d~b, that are present in these structures.

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30Mei1 - 73Kit1

Flükiger¹,

Wolf²

Nb, Nb-Al - Nb-Ge

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Normal and superconducting properties of niobium rich niobium-tantalum alloys

Cited by 18 publications

References 16 publications

A study on the effect of tantalum-impurity content on the superconducting properties of niobium materials used for making superconducting radio frequency cavities

A study on the effect of tantalum-impurity content on the superconducting properties of niobium materials used for making superconducting radio frequency cavities

Upper critical fields of periodic and quasiperiodic Nb-Ta superlattices

30Mei1 - 73Kit1

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