Magnetic shielding effects of the superposition of a ferromagnetic cylinder over an HTS cylinder: magnetic shielding dependence on the air gap between the BPSCCO and soft-iron cylinders

Omura, Atsushi; Oka, Masafumi; Mori, Kotaro; Itoh, M.

doi:10.1016/s0921-4534(02)02113-5

Cited by 15 publications

(18 citation statements)

References 4 publications

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“…One can notice that, for short open tubes, with ℓ/a 2 ≤ 2, the field attenuation at the centre is lower than 60 dB for all inductions. It is therefore not possible, according to (12), to determine B lim in these cases. In the range of ratios 2 ≤ ℓ/a 2 ≤ 6, the threshold induction can be defined, and it is found to be systematically higher for the closed tube than for the open one.…”

Section: Field Attenuation For Open and Closed Tubesmentioning

confidence: 99%

Field penetration into hard type-II superconducting tubes: effects of a cap, a non-superconducting joint, and non-uniform superconducting properties

Denis

Dirickx

Vanderbemden

et al. 2007

Supercond. Sci. Technol.

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Using the numerical method of Brandt (1998 Phys. Rev. B 58 6506), we study the penetration of a uniform magnetic field that is gradually applied parallel to the axis of finite type-II superconducting tubular samples with strong pinning. This study is carried out in view of designing low-frequency magnetic shields by exploiting the diamagnetic properties of type-II superconductors. First, we compare the field penetration into open and closed tubes. For long tubes (length larger than three times the outer diameter), we show that a cap weakly affects the maximum magnetic induction that can be shielded, but greatly increases the region over which the field is nearly uniform. When the length of the tube is shorter, both the maximum shieldable magnetic induction and the uniformity of the field attenuation are enhanced by closing the tube. We also show that making a hole in the cap, which is often necessary for applications, does not greatly affect the shielding properties provided the diameter of the hole is small compared to that of the tube (hole diameter smaller than a quarter of the outer tube diameter). In view of designing large size magnetic shields, superconducting tubes of finite size need to be joined together. We therefore examine in a second part how the presence of a non-superconducting joint between the tubes affects the shielding efficiency. It is shown that the effect of a joint depends upon its position along the tube axis and strongly increases with its size. Third, we study how non-uniform superconducting properties affect the shielding capabilities.

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Section: Field Attenuation For Open and Closed Tubesmentioning

confidence: 99%

Field penetration into hard type-II superconducting tubes: effects of a cap, a non-superconducting joint, and non-uniform superconducting properties

Denis

Dirickx

Vanderbemden

et al. 2007

Supercond. Sci. Technol.

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“…where J c is the critical current density, B ex the excitation magnetic flux density, B s the maximum shielded magnetic flux density [5] of the BPSCCO cylinder, and W the wall thickness of the BPSCCO cylinder. By making use of the Bean [4] model, the critical current density J c within x can be expressed as…”

Section: Resultsmentioning

confidence: 99%

Analysis of the magnetic distribution within a high-temperature superconductor magnetic shielding cylinder by use of the finite element method

Omura

Kotani

Yasu

et al. 2006

Journal of Physics and Chemistry of Solids

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“…The strong diamagnetic response of high-temperature superconductors offers the possibility to design superconducting magnetic shielding systems that can operate down to very low frequencies [1,2]. Because superconducting ceramics are very brittle, it is difficult to realise large magnetic shields (on the scale of tens of centimetres) of complex shapes.…”

Section: Introductionmentioning

confidence: 99%

Characterisation of the magnetic shielding properties of YBaCuO thick films prepared by electrophoretic deposition on silver substrates

Denis

Grenci

Dusoulier

et al. 2006

J. Phys.: Conf. Ser.

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Abstract. This communication reports experimental results on the superconducting properties of YBaCuO thick films prepared by electrophoretic deposition on silver substrates. The magnetic shielding properties of the coatings were characterised by various methods. First, the electrical resistance and the transport critical current density, J C , were determined. Our coatings exhibit a superconducting transition at a temperature of 90 K. Next, shielding characterisations were carried out at 77 K for samples having either a slab or a cylindrical geometry. In both cases, the frequency of the applied magnetic field was 103 Hz; the field behind the shielding wall was measured by a pick-up coil connected to a lock-in amplifier. In the case of cylindrical samples and for an applied induction lower than 1 G, the field inside the shielding enclosure is reduced by a factor greater than 10 6 (i.e. 120 dB) with respect to the applied field.

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Magnetic shielding effects of the superposition of a ferromagnetic cylinder over an HTS cylinder: magnetic shielding dependence on the air gap between the BPSCCO and soft-iron cylinders

Cited by 15 publications

References 4 publications

Field penetration into hard type-II superconducting tubes: effects of a cap, a non-superconducting joint, and non-uniform superconducting properties

Field penetration into hard type-II superconducting tubes: effects of a cap, a non-superconducting joint, and non-uniform superconducting properties

Analysis of the magnetic distribution within a high-temperature superconductor magnetic shielding cylinder by use of the finite element method

Characterisation of the magnetic shielding properties of YBaCuO thick films prepared by electrophoretic deposition on silver substrates

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