A portable magnetic field of &amp;gt;3 T generated by the flux jump assisted, pulsed field magnetization of bulk superconductors

Zhou, Difan; Ainslie, Mark; Shi, Yunhua; Dennis, Anthony; Huang, Kaiyuan; Hull, J.R.; Cardwell, D. A.; Durrell, John

doi:10.1063/1.4973991

Cited by 47 publications

(49 citation statements)

References 36 publications

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“…These observations have important implications for the determination of the optimum set of pulses that results in the maximum trapped field at a particular operating temperature. It has been previously shown experimentally [29], [39] that an initially partially-magnetised bulk (with an 'M-shaped' trapped field profile) can result in high trapped fields; this is not observed within this numerical simulation framework. This phenomenon may be strongly related to flux jumps during the pulse rise time that can assist the PFM process [18], [28], [29], [40], [41], which also are not observed within this framework.…”

Section: Pulsed Field Magnetisation -Multi-pulse Results -2 Nd Pulsementioning

confidence: 68%

“…It has been previously shown experimentally [29], [39] that an initially partially-magnetised bulk (with an 'M-shaped' trapped field profile) can result in high trapped fields; this is not observed within this numerical simulation framework. This phenomenon may be strongly related to flux jumps during the pulse rise time that can assist the PFM process [18], [28], [29], [40], [41], which also are not observed within this framework. This suggests that some techniques, such as the iteratively magnetising pulsed-field method with reducing amplitude (IMRA) [7], may be not be as effective without assistive flux jumps.…”

Section: Pulsed Field Magnetisation -Multi-pulse Results -2 Nd Pulsementioning

confidence: 68%

“…where I 0 is the peak magnitude of the current flowing in each turn of the coil, N is the number turns, and τ = 15 ms is the rise time of all pulses in this study, a typical value for standard PFM experiments carried out at Iwate University [17], [27]. In other works, the rise time varies between a few ms to several 10s of ms, depending on the type of magnetising coil, its inductance/resistance, whether any ferromagnetic materials are used and so on [17], [28], [29]. The magnetising fixture has the same coil constant, relating Bapp, the field at the centre of the magnetising fixture with the bulk removed to the applied current, as presented in [17], [18].…”

Section: Numerical Simulation Frameworkmentioning

confidence: 99%

See 2 more Smart Citations

Toward Optimization of Multi-Pulse, Pulsed Field Magnetization of Bulk High-Temperature Superconductors

Ainslie

Srpcic

Zhou

et al. 2018

IEEE Trans. Appl. Supercond.

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Pulsed field magnetisation (PFM) is the most practical method for magnetising bulk superconducting materials as trapped field magnets (TFMs), but the record trapped field achieved by PFM to date is still significantly less than the true trapped field capability of these materials. In this paper, a flexible numerical modelling technique based on the finite element method is used to provide a comprehensive and realistic picture of multi-pulse PFM, which has been shown to be effective in increasing the trapped field/flux over a single pulse. Firstly, the maximum trapped field capability of a representative sample is determined using two types of numerical model simulating fieldcooling (FC) and zero-field-cooling (ZFC) magnetisation. Next, various sets of magnetic field pulses are applied to the bulk to analyse multi-pulse PFM. An increase in the trapped field can be achieved after a 2 nd pulse and to do so an increased amplitude of applied field is required to maximize the trapped field fully. The numerical analysis shows that this occurs in subsequent pulses because it is more difficult for the magnetic flux to penetrate the sample and there is a lower temperature rise.  Index Terms-Bulk high-temperature superconductors, finite element method, numerical simulation, pulsed field magnetization, trapped field magnets. I. INTRODUCTIONULK superconducting materials can be used as trapped field magnets (TFMs) and magnetic fields greater than 17 T have been achieved in large, single-grain (RE)BCO (where RE = rare earth or Y) bulk high-temperature superconductors [1], [2]. However, developing practical magnetising techniques is crucial to using them as TFMs in engineering applications, such as rotating machines, magnetic separation and magnetic drug delivery systems [3]- [5].Pulsed field magnetisation (PFM) is the most practical M. D. Ainslie would like to acknowledge financial support from a Royal Academy of Engineering Research Fellowship and an Engineering and Physical Sciences Research Council (EPSRC) Early Career Fellowship EP/P020313/1. Additional data related to this publication are available at the University of Cambridge data repository (

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Section: Pulsed Field Magnetisation -Multi-pulse Results -2 Nd Pulsementioning

confidence: 68%

Section: Pulsed Field Magnetisation -Multi-pulse Results -2 Nd Pulsementioning

confidence: 68%

Section: Numerical Simulation Frameworkmentioning

confidence: 99%

See 1 more Smart Citation

Toward Optimization of Multi-Pulse, Pulsed Field Magnetization of Bulk High-Temperature Superconductors

Ainslie

Srpcic

Zhou

et al. 2018

IEEE Trans. Appl. Supercond.

Self Cite

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“…Such superconducting bulks, magnetized by field-cooled magnetization (FCM) as a so-called trapped field magnet (TFM), can trap magnetic flux inside the bulk due to the "vortex pinning effect" and generate quasi-permanent magnetic fields over 17 T at magnetizing temperatures below 30 K. A record-high trapped field of 17.6 T has been reliably achieved by FCM at 26 K in the gap between two GdBaCuO disk bulks of 25 mm in diameter [15][16]. Pulsed-field magnetization (PFM) is also known as a key magnetizing technique to develop a desktop and mobile magnetizing system, for which the dynamic magnetic flux behavior and the resultant heat generation inside the bulk have been carefully investigated to improve trapped fields using PFM [17][18][19]. The record-high trapped field by PFM is 5.2 T at 28 K on the surface of a 45 mm diameter GdBaCuO disk bulk [20], and 5.3 T at 30 K in the gap between two 25 mm diameter GdBaCuO disk bulks [21].…”

Section: Introductionmentioning

confidence: 99%

Simulation study for magnetic levitation in pure water exploiting the ultra-high magnetic field gradient product of a hybrid trapped field magnet lens (HTFML)

Takahashi

Fujishiro

Ainslie

2020

Journal of Applied Physics

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A hybrid trapped field magnet lens (HTFML) is a promising device that is able to concentrate a magnetic field higher than the applied field continuously, even after removing an external field, which was conceptually proposed by the authors in 2018. In this study, we propose a new additional advantage of the HTFML, which could be applicable for magnetic levitation and separation. The HTFML device consisting of GdBaCuO bulk cylinder and GdBaCuO magnetic lens, after the magnetization process from an applied field, Bapp = 10 T, can generate a maximum trapped field, Bc = 11.4 T, as well as an ultra-high magnetic field gradient product, Bz•dBz/dz, over ±3,000 T 2 /m at Ts = 20 K, which is higher than that of existing superconducting magnets (SM) and large-scale hybrid magnets (HM). Through detailed numerical simulations, the HTFML device is considered for magnetic separation of a mixture of precious metal particles (Pt, Au, Ag and Cu) dispersed in pure water, by exploiting the magneto-Archimedes effect. The HTFML can be realized as a compact and mobile desktop-type superconducting bulk magnet system and there are a wide range of potential industrial applications, such as in the food and medical industries.

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“…We propose a mechanism for the magnetic moment inversion. Blocking of such inversion is crucial for the application of bulk superconductors as “permanent” magnet in power systems 19–21 .…”

Section: Introductionmentioning

confidence: 99%

Magnetic moment inversion at giant flux jump: dynamical property of critical state in type-II superconductors

Chabanenko

Puźniak

Kuchuk

et al. 2019

Sci Rep

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Experimental evidence of tremendous magnetic moment dynamical inversion, from metastable trapping state to the state with essentially the same moment oriented in the opposite direction, appearing during giant flux jump connected to thermomagnetic avalanche process in superconducting YBa 2 Cu 3 O 7− δ single crystal, is presented. Magnetization inversion takes place in the system, without thermal contact between sample and sample holder, with a tremendous stored energy once the avalanche process is completed in quasi-adiabatic conditions. A model of magnetic moment inversion, caused by the jump between two metastable states of superconductor with the same energy storage, is presented and discussed in terms of the critical state with peculiar evolution of the critical-current spatial distribution. Importantly, knowledge of conditions of the appearance of such a phenomenon is crucial for applications of bulk superconductors as “permanent” magnets, for example, in superconducting levitation devices, etc.

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A portable magnetic field of >3 T generated by the flux jump assisted, pulsed field magnetization of bulk superconductors

Cited by 47 publications

References 36 publications

Toward Optimization of Multi-Pulse, Pulsed Field Magnetization of Bulk High-Temperature Superconductors

Toward Optimization of Multi-Pulse, Pulsed Field Magnetization of Bulk High-Temperature Superconductors

Simulation study for magnetic levitation in pure water exploiting the ultra-high magnetic field gradient product of a hybrid trapped field magnet lens (HTFML)

Magnetic moment inversion at giant flux jump: dynamical property of critical state in type-II superconductors

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