Magnetic shielding studies using cylinders of YBa2Cu3O7−x prepared by isostatic compression
TL;DR: In this paper, the shielding properties of cylindrical pots of YBa 2 Cu 3 O 7−x (YBCO) prepared by isostatic compression were measured at 77 K for d.c. magnetic fields in the range of frequencies from 100 Hz to 5 KHz.
About: This article is published in Solid State Communications.The article was published on 1993-09-01. It has received 2 citations till now. The article focuses on the topics: Electromagnetic shielding & Magnetic field.
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TL;DR: In this paper, a complete procedure to achieve multilayer YBa2Cu3O7−δ (YBCO) thick films by electrophoretic deposition on silver tubes using a suspension of YBCO powder in butanol was reported.
Abstract: We report a complete procedure to achieve multilayer YBa2Cu3O7−δ (YBCO) thick films by electrophoretic deposition on silver tubes using a suspension of YBCO powder in butanol. With the aim to optimize the magnetic shielding performances of the coatings, we have carried out an extensive investigation of the influence of the deposition parameters, the multilayer deposition sequence and the intermediate/final heat treatments on the coating microstructure. Using the optimized conditions, a 24-layer YBCO coating has been successfully prepared on an 80 mm long Ag tube: the melt growth processed multilayered YBCO thick film thus obtained can shield an applied magnetic field of 1.9 mT at 77 K, the highest value per thickness unit reported so far in the literature for these materials.
4 citations
TL;DR: In this article, magnetic shielding studies have been carried out to investigate the usefulness of high-Tc YBCO ceramics for EMS applications, where cylinders were prepared by uniaxial compresssion and isostatic compression, with and without Ag additive.
Abstract: Magnetic shielding studies have been carried out to investigate the usefulness of high-Tc YBCO ceramics for EMS applications. The starting materials were single-phase YBCO powder. The cylinders were prepared by uniaxial compresssion and isostatic compression, with and without Ag additive. The shielding fieldH*, defined as the value of the applied field at which a detectable field will be seen inside the superconducting shield, was 12 G for the shield prepared by uniaxial compression and around 17 G for shields prepared by isostatic compression. Measurements were done in both ac and dc fields. The field inside the shield for the sinusoidal ac applied field is highly distorted, showing the presence of three higher harmonics. The penetrated waveform was Fourier-analyzed to yield the rms value ofBin. When the normalized value ofB was plotted against the normalized value ofH with respect toH*, all the points corresponding to different shields fall on the same curve.
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TL;DR: Experimental results and phenomenological theory based on the sponge model for hysteretic high-field superconductors are given in this article, where the response of the supercondors to alternating fields superimposed upon steady fields is studied.
Abstract: Experimental results and phenomenological theory based on the sponge model for hysteretic high-field superconductors are given. After developing the exposition for static magnetization, the response of the superconductors to alternating fields superimposed upon steady fields is studied. (T.F.H.)
3,634 citations
TL;DR: In this article, the authors measured the magnetic field H' at the center of a hollow of sintered Y-Ba-Cu-O superconductor as a function of applied field H, temperature, tube length, and tube wall thickness.
Abstract: The authors have measured the magnetic field H' at the center of a hollow of sintered Y-Ba-Cu-O superconductor as a function of applied field H, temperature, tube length, and tube wall thickness. The maximum field that can be shielded H/sub sh/ agrees with the value calculated from the critical state model using the measured critical-current density J/sub c/. The maximum trapped field H/sub tr/ in the tube, on decreasing H to zero, exceeds H/sub sh/ by as much as a factor of two, and large enhancements in J/sub c/ are observed in the decreasing field. These phenomena are identified with intragranular flux pinning present only after H has exceeded H/sub c1/ of the grains. Finite tube length does not affect the H/sub tr//H/sub sh/ ratio appreciably. H/sub sh/ depends approximately on the square root of the wall thickness. >
67 citations
TL;DR: In this paper, high-Tc superconducting tubes have been developed for magnetic shielding of SQUIDs at 77 K. The characteristics of such tubes show that adequate shielding exists for magnetic fields up to a critical field determined by the current density of the tube.
Abstract: High‐Tc superconducting tubes have been developed for magnetic shielding of SQUIDs at 77 K. The characteristics of such tubes show that adequate shielding exists for magnetic fields up to a critical field determined by the current density of the tube. Relaxation phenomena with two different time dependencies are observed when the external magnetic field enters the tubes.
32 citations
TL;DR: In this article, the magnetic shielding has been investigated by measuring magnetic coupling between primary and secondary coils separated by a high-Tc superconductor, which can explain the existence of superconductivity related surface current, which flows out from front to rear surface to couple with the secondary coil.
Abstract: The magnetic shielding has been investigated by measuring magnetic coupling between primary and secondary coils separated by a high-Tc superconductor. The magnetic coupling between primary and secondary coils could not be zero below Tc. This can be explained by the existence of superconductivity related surface current, which flows out from front to rear surface to couple with the secondary coil.
28 citations
TL;DR: In this paper, the microstructure of polycrystalline YBa/sub 2/Cu/sub 3/O/sub 7-x/ tubes was determined by scanning electron microscopy and X-ray diffractometry.
Abstract: Tubes fabricated of polycrystalline YBa/sub 2/Cu/sub 3/O/sub 7-x/ are characterized, and details of the fabrication procedure are discussed. The microstructure of the tubes determined by scanning electron microscopy and X-ray diffractometry is described. Resistive measurements of T/sub c/ and Delta T/sub c/ have been made. The tubes have also been characterized by means of SQUID (superconducting quantum interference device) magnetometry. The temperature dependence of magnetic fields trapped axially in the tubes has been measured and estimates of penetration depth are given. Moreover, measurements of the transverse shielding effectiveness of the tubes have been made and are compared with theoretical predictions. Studies on flux penetration into the tubes are described. Findings from the microstructure studies are correlated with the observed superconductivity properties. The results on the high-temperature materials are compared to results obtained previously on tubes made from conventional superconductors. >
27 citations