Optimization of Thermal Material in a Flux Pump System With High Temperature Superconductor

Hsu, C. H.; Yu, You‐Jun; Hadeler, O.; Vertruyen, Bénédicte; Granados, X.; Coombs, Tim

doi:10.1109/tasc.2011.2175891

Cited by 7 publications

(7 citation statements)

References 8 publications

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“…Ti-doped Cu-Zn ferrite ceramics were prepared using the solid-state reaction method described in details in references [9,10]. High-purity powders of CuO, ZnO, TiO2 and FeC2O4 ⋅ 2 H2O were mixed homogeneously and progressively heated to 1200°C with an intermediate grinding.…”

Section: Methodsmentioning

confidence: 99%

“…">IntroductionDue to the combination of excellent magnetic properties at high frequency and low price, ferrite materials have become essential materials in a wide range of electrical engineering applications including chip components, filters, telecommunication systems, sensors [1-5] and extending to biomedical applications and energy storage [6][7][8]. This present work deals with ferrites to be inserted in an innovative low-temperature application related to the magnetization of type-II superconductors used as permanent magnets [9,10]. Unlike a classical ferromagnet where the magnetization is limited physically by the alignment of all microscopic magnetic moments, the remnant magnetization of a type-II irreversible superconductor is generated by macroscopic (resistanceless) supercurrent current loops [11,12].…”

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confidence: 99%

“…Flux pumping involves creating a travelling magnetic field wave that guides magnetic flux lines toward the center of the superconducting element.The technique can be applied to films, bulk samples or coils [27]. The travelling wave can be produced by a moving magnet [26], a three-phase coil system [28] or by making use of the so-called "Thermally Actuated Magnetization" (TAM) [9,10,25]. In the latter, the bulk superconductor is placed below a magnetic disk exhibiting a clear phase transition at some (Curie) temperature T c, as shown schematically in figure 1(a).…”

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confidence: 99%

“…investigated: these including manganites [32] or ferrites [33]. Among the several chemical compositions investigated in Ti-doped Ni-Zn and Cu-Zn ferrites, the most promising results were obtained from Cu0.3Zn0.7Ti0.04Fe1.96O4 and Mg0.15Cu0.15Zn0.7Ti0.04Fe1.96O4 stoichiometry [9,10]. Their critical temperature is much lower than that of commercial ferrites, while their magnetic properties remain weakly affected.…”

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confidence: 99%

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Thermal properties of Ti-doped Cu–Zn soft ferrites used as thermally actuated material for magnetizing superconductors

Stachowiak

Mucha

Szewczyk

et al. 2016

J. Phys. D: Appl. Phys.

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A great majority of widely used ferrite ceramics exhibit a relatively high temperature of order-disorder phase transition in their magnetic subsystem. For applications related to the magnetization process of superconductors, however, a low value of Tc is required. Here we report and analyze in detail the thermal properties of bulk Ti-doped Cu-Zn ferrite ceramics Cu0.3Zn0.7Ti0.04Fe1.96O4 and Mg0.15Cu0.15Zn0.7Ti0.04Fe1.96O4. They are characterized by a Curie temperature in the range 120-170 K and a maximum DC magnetic susceptibility exceeding 20 for the Cu0.3Zn0.7Ti0.04Fe1.96O4 material. The temperature dependence of both the specific heat Cp and of the thermal conductivity κ, determined between 2 and 300 K, are found not to exhibit any peculiar feature at the magnetic transition temperature. The low-temperature dependence of both κ and the mean free path of phonons suggests a mesoscopic fractal structure of the grains. From the measured data, the characteristics of thermally actuated waves are estimated. The low magnetic phase transition temperature and suitable thermal parameters make the investigated ferrite ceramics applicable as magnetic wave producers in devices designed for magnetization of high-temperature superconductors. IntroductionDue to the combination of excellent magnetic properties at high frequency and low price, ferrite materials have become essential materials in a wide range of electrical engineering applications including chip components, filters, telecommunication systems, sensors [1-5] and extending to biomedical applications and energy storage [6][7][8]. This present work deals with ferrites to be inserted in an innovative low-temperature application related to the magnetization of type-II superconductors used as permanent magnets [9,10]. Unlike a classical ferromagnet where the magnetization is limited physically by the alignment of all microscopic magnetic moments, the remnant magnetization of a type-II irreversible superconductor is generated by macroscopic (resistanceless) supercurrent current loops [11,12]. When prepared in bulk form, e.g. monolithic disks of a few centimeters in diameter [13][14][15][16], superconductors are able to trap magnetic flux densities exceeding 3 teslas [11,[17][18][19], which opens up new horizons in terms of applications [20][21][22]. One of the main issues, however, is that these superconducting materials need to be magnetized before their use. In addition to the well-established magnetization techniques, -namely, zero field cooling (ZFC), field cooling (FC) and pulse field magnetization (PFM) [23] -, there is a growing interest in applying the so-called "flux pump" technology[24] to the magnetization of bulk superconductors [25,26]. Flux pumping involves creating a travelling magnetic field wave that guides magnetic flux lines toward the center of the superconducting element.The technique can be applied to films, bulk samples or coils [27]. The travelling wave can be produced by a moving magnet [26], a three-phase coil system [28] or by making use of the ...

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Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Thermal properties of Ti-doped Cu–Zn soft ferrites used as thermally actuated material for magnetizing superconductors

Stachowiak

Mucha

Szewczyk

et al. 2016

J. Phys. D: Appl. Phys.

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“…Among various materials, ferrites, which are chemical compounds consisting of ceramic materials with iron(III) oxide as their principal component, are a good TAM for future flux pumping technology because of the significant relative permeability change with temperature, particularly around the Curie point [5]. More importantly, their magnetic and thermal properties can be greatly varied by adding up different dopants such as Mg or Ti which can change their ceramic structures microscopically [6].…”

Section: Introductionmentioning

confidence: 99%

Soft Ferrite Used as Thermal-Magnetic Conversion Intermedium in the Flux Pumping Technology

Zhai

Hsu

Spaven

et al. 2013

IEEE Trans. Appl. Supercond.

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Recent progress in material science has proved that high-temperature superconductors, such as bulk melt-processed yttrium barium copper oxide (YBCO) single domains, have a great potential to trap significant magnetic fields. In this paper, we will describe a novel method of YBCO magnetization that only requires the applied field to be at the level of a permanent magnet. Instead of applying a pulsed high magnetic field on the YBCO, a thermally actuated material (TAM), such as Mg 0.15 Cu 0.15 Zn 0.7 Ti 0.04 Fe 1.96 O 4 , has been used as an intermedium to create a travelling magnetic field by changing the local temperature so that the local permeability is changed to build up the magnetization of the YBCO gradually after multiple pumping cycles. It is well known that the relative permeability of ferrite is a function of temperature and its electromagnetic properties can be greatly changed by adding dopants such as Mg or Ti; therefore, it is considered to be the most promising TAM for future flux pumping technology. Ferrite samples were fabricated by means of the conventional ceramic method with different dopants. Zinc and iron oxides were used as raw materials. The samples were sintered at 1100 • C, 1200 • C, and 1300 • C. The relative permeability of the samples was measured at temperatures ranging from 77 to 300 K. This work investigates the variation of the magnetic properties of ferrites with different heat treatments and doping elements and gives a smart insight into finding better ferrites suitable for flux pumping technology.

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Flux pumping, fluctuations and climbing fields

Coombs

Hadeler

Zhang

et al. 2012

Supercond. Sci. Technol.

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This paper describes the behaviour of bulk superconductors when subjected to a varying magnetic field. A magnetic model is described together with experimental results which explain and describe the behaviour of superconducting bulks when subjected to varying magnetic fields. We demonstrate how the behaviour is dependent on the magnitude and period of the perturbations in the fields. The model which we use has been implemented using the Comsol TM pde solver. It is a fully integrated model which uses a variable heat source to regulate the magnetic circuit and thereby to achieve flux pumping. Comsol TM is used for post solution visualization and the model is presented alongside experimental results which support and confirm the conclusions from the model.

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Optimization of Thermal Material in a Flux Pump System With High Temperature Superconductor

Cited by 7 publications

References 8 publications

Thermal properties of Ti-doped Cu–Zn soft ferrites used as thermally actuated material for magnetizing superconductors

Thermal properties of Ti-doped Cu–Zn soft ferrites used as thermally actuated material for magnetizing superconductors

Soft Ferrite Used as Thermal-Magnetic Conversion Intermedium in the Flux Pumping Technology

Flux pumping, fluctuations and climbing fields

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