Simple magnetic shielding experiment on high Tc superconducting bulk ceramics and thin films, metals and alloys

Hussain, A.A.; Sayer, M.

doi:10.1016/0011-2275(92)90347-d

Cited by 18 publications

(5 citation statements)

References 6 publications

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“…In [15], the field attenuation due to a thick BSCCO film on a cylindrical silver substrate was found to be frequency-independent. The same results were established for superconducting disks made from YBCO powder and subjected to perpendicular fields [20,21]. Yet other studies on bulk BSCCO tubes [3,22] measured a field attenuation that decreases with frequency, whereas the attenuation was shown to slowly increase with frequency for a YBCO superconducting tube [23].…”

Section: Introductionsupporting

confidence: 72%

“…To evaluate B lim , one could then use (20), which for 6a 2 , is close to H P∞ = J c d. However, this formula can be misleading for understanding the influence of the wall thickness, d. Expressions (20) or H P∞ = J c d were established, ignoring the variation of J c with B and show a linear dependence of B lim as a function of d. However, the decrease of J c with the local induction yields a softer dependence as can be seen in (18). There, B lim ≈ B lim,∞ is linear in d only for thicknesses d much smaller than B 1 /(2μ 0 J c0 ) ≈ 0.1 mm, but grows as √ d for larger thicknesses if one takes the J c0 and B 1 parameters of section 4.2.…”

Section: Uniformity Of the Field Attenuation In A Superconducting Tubementioning

confidence: 99%

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Spectra of quantum systems in superstrong inertial force fields

Денисов¹,

Kravtsov²

2002

Quantum Electron.

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We have experimentally studied the magnetic shielding properties of a cylindrical shell of BiPbSrCaCuO subjected to low frequency AC axial magnetic fields. The magnetic response has been investigated as a function of the dimensions of the tube, the magnitude of the applied field and the frequency. These results are explained quantitatively by employing the method of Brandt (1998 Phys. Rev. B 58 6506) with a J c (B) law appropriate for a polycrystalline material. Specifically, we observe that the applied field can sweep into the central region either through the thickness of the shield or through the opening ends, the latter mechanism being suppressed for long tubes. For the first time, we systematically detail the spatial variation of the shielding factor (the ratio of the applied field over the internal magnetic field) along the axis of a high-temperature superconducting tube. The shielding factor is shown to be constant in a region around the centre of the tube, and to decrease as an exponential in the vicinity of the ends. This spatial dependence comes from the competition between two mechanisms of field penetration. The frequency dependence of the shielding factor is also discussed and shown to follow a power law arising from the finite creep exponent n.

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Section: Introductionsupporting

confidence: 72%

Section: Uniformity Of the Field Attenuation In A Superconducting Tubementioning

confidence: 99%

Spectra of quantum systems in superstrong inertial force fields

Денисов¹,

Kravtsov²

2002

Quantum Electron.

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“…In the limit → ∞, one recovers the Bean limit H P∞ = J c a 2 . An approximate expression of H P for a tube can be obtained with the energy minimization approach developed in [34]: (20) with δ = a 1 /a 2 . An interesting observation is that (20) can be rewritten as…”

Section: Modelling Of the Field Penetration Into A Hts Tubementioning

confidence: 99%

“…When 6a 2 , the value of B lim is very close to the applied field for which the sample is fully penetrated, as the main penetration mechanism is the nonlinear diffusion through the superconducting wall. To evaluate B lim , one could then use (20), which for 6a 2 , is close to H P∞ = J c d. However, this formula can be misleading for understanding the influence of the wall thickness, d. Expressions (20) or H P∞ = J c d were established, ignoring the variation of J c with B and show a linear dependence of B lim as a function of d. However, the decrease of J c with the local induction yields a softer dependence as can be seen in (18). There, B lim ≈ B lim,∞ is linear in d only for thicknesses d much smaller than B 1 /(2μ 0 J c0 ) ≈ 0.1 mm, but grows as √ d for larger thicknesses if one takes the J c0 and B 1 parameters of section 4.2.…”

Section: Uniformity Of the Field Attenuation In A Superconducting Tubementioning

confidence: 99%

Magnetic shielding properties of high-temperature superconducting tubes subjected to axial fields

Denis

Dusoulier

Dirickx

et al. 2007

Supercond. Sci. Technol.

110

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We have experimentally studied the magnetic shielding properties of a cylindrical shell of BiPbSrCaCuO subjected to low frequency AC axial magnetic fields. The magnetic response has been investigated as a function of the dimensions of the tube, the magnitude of the applied field and the frequency. These results are explained quantitatively by employing the method of Brandt (1998 Phys. Rev. B 58 6506) with a Jc(B) law appropriate for a polycrystalline material. Specifically, we observe that the applied field can sweep into the central region either through the thickness of the shield or through the opening ends, the latter mechanism being suppressed for long tubes. For the first time, we systematically detail the spatial variation of the shielding factor (the ratio of the applied field over the internal magnetic field) along the axis of a high-temperature superconducting tube. The shielding factor is shown to be constant in a region around the centre of the tube, and to decrease as an exponential in the vicinity of the ends. This spatial dependence comes from the competition between two mechanisms of field penetration. The frequency dependence of the shielding factor is also discussed and shown to follow a power law arising from the finite creep exponent n.

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“…So the shielding materials of superconductor can easily be obtained. Some experiments have been done recently in this field [8], but the superconductor shielding theory still needs improving.…”

mentioning

confidence: 99%

Shielding Performance of Superconducting Structures

Eleiwa¹

2006

The International Conference on Electrical Engineering

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Electromagnetic shielding is one of the most promising applications of superconductors that still needs further investigation. An enhanced model is therefore proposed to design optimum shielding structures made from different low and high criticaltemperature (LTS & HTS) superconductors. The proposed model incorporates classical electrodynamics with both superconductivity macroscopic theories such as two-fluid model, Ginzburg-Landau (GL) theory, and microscopic Bardeen-Cooper-Schrieffer (BCS) theory. Thermodynamic properties are also included using improved Gorter-Casimir relations based on published experimental data. General shielding effectiveness expressions are derived for different superconducting shielding structures against generally polarized incident electromagnetic waves. A computer algorithm is then developed to investigate the impact of superconducting material parameters on shielding effectiveness. The limitations and advantages of superconducting shielding structures are also discussed.

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Simple magnetic shielding experiment on high Tc superconducting bulk ceramics and thin films, metals and alloys

Cited by 18 publications

References 6 publications

Spectra of quantum systems in superstrong inertial force fields

Spectra of quantum systems in superstrong inertial force fields

Magnetic shielding properties of high-temperature superconducting tubes subjected to axial fields

Shielding Performance of Superconducting Structures

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