A review and prospects for Nb3Sn superconductor development

Xu, Xingchen

doi:10.1088/1361-6668/aa7976

Title: A review and prospects for Nb₃Sn superconductor development

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Abstract

Nb₃Sn superconductors have significant applications in constructing high-field (> 10 T) magnets. This article briefly reviews development of Nb₃Sn superconductor and proposes prospects for further improvement. It is shown that significant improvement of critical current density (J_c) is needed for future accelerator magnets. After a brief review of the development of Nb₃Sn superconductors, the factors controlling J_c are summarized and correlated with their microstructure and chemistry. The non-matrix J_c of Nb₃Sn conductors is mainly determined by three factors: the fraction of current-carrying Nb₃Sn phase in the non-matrix area, the upper critical field B_c2, and the flux-line pinning capacity. Then prospects to improve the three factors are discussed respectively. An analytic model was developed to show how the ratios of precursors determine the phase fractions after heat treatment, based on which it is predicted that the limit of current-carrying Nb₃Sn fraction in subelements is ~65%. Then, since B_c2 is largely determined by the Nb₃Sn stoichiometry, a thermodynamic/kinetic theory was presented to show what essentially determines the Sn content of Nb₃Sn conductors. This theory explains the influences of Sn sources and Ti addition on stoichiometry and growth rate of Nb₃Sn layers. Next, to improve flux pinning, previous efforts in this community tomore »« less

Authors:

Xu, Xingchen ^[1]

Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

Publication Date:: Thu Aug 03 00:00:00 EDT 2017

Research Org.:: Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

Sponsoring Org.:: USDOE Office of Science (SC), High Energy Physics (HEP)

OSTI Identifier:: 1409076

Report Number(s):: arXiv:1706.10253; FERMILAB-PUB-17-086-TD
Journal ID: ISSN 0953-2048; 1608205

Grant/Contract Number:: AC02-07CH11359

Resource Type:: Accepted Manuscript

Journal Name:: Superconductor Science and Technology

Additional Journal Information:: Journal Volume: 30; Journal Issue: 9; Journal ID: ISSN 0953-2048

Publisher:: IOP Publishing

Country of Publication:: United States

Language:: English

Subject:: 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; Nb3Sn; critical current density Jc; stoichiometry; area fraction; flux pinning; APC

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                    Xu, Xingchen. A review and prospects for Nb3Sn superconductor development.  United States: N. p., 2017. 
Web.  doi:10.1088/1361-6668/aa7976.

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                    Xu, Xingchen. A review and prospects for Nb3Sn superconductor development.  United States.  https://doi.org/10.1088/1361-6668/aa7976

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                    Xu, Xingchen. Thu .  
"A review and prospects for Nb3Sn superconductor development".  United States.  https://doi.org/10.1088/1361-6668/aa7976.  https://www.osti.gov/servlets/purl/1409076.

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@article{osti_1409076,

  title        = {A review and prospects for Nb3Sn superconductor development},

  author       = {Xu, Xingchen},

  abstractNote = {Nb3Sn superconductors have significant applications in constructing high-field (> 10 T) magnets. This article briefly reviews development of Nb3Sn superconductor and proposes prospects for further improvement. It is shown that significant improvement of critical current density (Jc) is needed for future accelerator magnets. After a brief review of the development of Nb3Sn superconductors, the factors controlling Jc are summarized and correlated with their microstructure and chemistry. The non-matrix Jc of Nb3Sn conductors is mainly determined by three factors: the fraction of current-carrying Nb3Sn phase in the non-matrix area, the upper critical field Bc2, and the flux-line pinning capacity. Then prospects to improve the three factors are discussed respectively. An analytic model was developed to show how the ratios of precursors determine the phase fractions after heat treatment, based on which it is predicted that the limit of current-carrying Nb3Sn fraction in subelements is ~65%. Then, since Bc2 is largely determined by the Nb3Sn stoichiometry, a thermodynamic/kinetic theory was presented to show what essentially determines the Sn content of Nb3Sn conductors. This theory explains the influences of Sn sources and Ti addition on stoichiometry and growth rate of Nb3Sn layers. Next, to improve flux pinning, previous efforts in this community to introduce additional pinning centers (APC) to Nb3Sn wires are reviewed, and an internal oxidation technique is described. Lastly, prospects for further improvement of non-matrix Jc of Nb3Sn conductors are discussed, and it is seen that the only opportunity for further significantly improving Jc lies in improving the flux pinning.},

  doi          = {10.1088/1361-6668/aa7976},

  journal      = {Superconductor Science and Technology},

  number       = 9,

  volume       = 30,

  place        = {United States},

  year         = {Thu Aug 03 00:00:00 EDT 2017},

  month        = {Thu Aug 03 00:00:00 EDT 2017}

}

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Title: A review and prospects for Nb3Sn superconductor development

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Title: A review and prospects for Nb₃Sn superconductor development