Improvement of Critical Current Densities in Bulk Superconductors of the 123-Type

Muralidhar, M.; Koblischka, Michael Rudolf; Murakami, Masato

doi:10.1002/(sici)1521-396x(199902)171:2<r7::aid-pssa99997>3.0.co;2-9

Cited by 11 publications

(16 citation statements)

References 7 publications

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“…As the critical current density is inversely proportional to the particle size [59,60], the Gd-211 particles are particularly important for the enhancement of the low-field critical current densities. Earlier studies [61] on the NEG-123 system found a similar effect and suggested that in the partially melted regime there are two kinds of LRE-211 inclusions: one intentionally added as an initial powder and another one produced by the peritectic decomposition of LRE-123. Since the decomposition temperature of Gd-123 is the lowest among the four rare earth elements Nd,Eu,Sm,Gd [12], Gd-211 has a chance to nucleate at relatively low temperatures, which may lead to small SPP size.…”

Section: Transmission Electron Microscopy and Edx Analysismentioning

confidence: 70%

“…In the REBa 2 Cu 3 O y system a large number of crystal defects are present in the 123 matrix that can act as effective pinning centres [50][51][52][53]. In addition to the crystal defects, fine dispersion of insulating 211 secondary phase particles are known to be effective in enhancing flux pinning at low fields [54][55][56][57][58]. The smaller the size of these particles, the more effective flux pinning is on them.…”

Section: Microstructurementioning

confidence: 99%

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Progress in melt-processed (Nd Sm Gd)Ba₂Cu₃O_ysuperconductors

Muralidhar

Jirsa²,

Sakai

et al. 2002

Supercond. Sci. Technol.

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This comprehensive survey deals with the melt-growth process and characterization of the novel class of ternary materials, (Nd,Sm,Gd)Ba 2 Cu 3 O y 'NSG-123'. Microstructure observations by optical microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) revealed the presence of sub-micron secondary phase (RE 2 BaCuO 5 , 211) particles uniformly dispersed in the 123 matrix that enhance flux pinning at low fields and improve the performance of this material. The energy-resolved TEM-EDX analysis clarified that small particles consist mainly of Gd 2 BaCuO 5 'Gd-211', irrespective of the initially added secondary phase (Gd-211 or NSG-211). Dark-field TEM observations showed that the NSG-123 matrix had a high density of RE-rich RE 1+x Ba 2−x Cu 3 O y (RE-123ss) clusters 3-10 nm in size. These small clusters enhance pinning at intermediate fields. The scaling analyses of the volume pinning force density at 77 K made on NSG-123 samples with varying 211 contents of various secondary phases showed the secondary peak at normalized fields as high as 0.45, which might indicate the activation of T c pinning mechanism. Trapped field measurements proved that silver was the key element to improve the mechanical strength of NSG-123 materials. Record trapped-field values at high magnetic fields can be obtained at 77 K with appropriately large sized NSG-123 samples.

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Section: Transmission Electron Microscopy and Edx Analysismentioning

confidence: 70%

Section: Microstructurementioning

confidence: 99%

Progress in melt-processed (Nd Sm Gd)Ba₂Cu₃O_ysuperconductors

Muralidhar

Jirsa²,

Sakai

et al. 2002

Supercond. Sci. Technol.

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“…HE new kinds of High Temperature Superconductors (HTS) are promising materials for the permanent magnet applications [1]- [5]. The superconducting bulks can play many roles in the industrial applications: the application of magnetic bearings [6], [7], and the application of high power density rotating machines [8]- [12] because it can trap or shield a high value of magnetic fields [13]- [16].…”

Section: Introductionmentioning

confidence: 99%

Improvement of the Magnetization of a Superconducting Bulk using an Iron Core

Gony

Berger

Douine

et al. 2015

IEEE Trans. Appl. Supercond.

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In most studies, the magnetization was carried out without the iron core which is not the case in superconducting electrical applications. So in this paper we study the magnetization of YBCO bulk using a Pulsed Field Magnetization method in a symmetrical iron core. This iron core has the same structure as the iron core in an electrical motor. We have tested a new process of magnetization, firstly without the iron core and secondly with the iron core where we find an enhancement about 36 % of the trapped magnetic field. The contribution of the iron core in this improvement was discussed. These experimentations help to carry out the magnetization of the superconducting bulk in the superconducting motor or in the coupling applications.

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“…Transmission electron microscopy revealed that the smallest RE-211 particles contained Gd, while most of the larger particles consisted of NEG-211 with the chemical ratio of 1:1:1. Since the smaller particles are the more effective in enhancing J c values, we prepared NEG-123 samples with an addition of only Gd-211 and achieved a very fine dispersion of Gd-211 particles in the NEG-123 matrix [21,26].…”

Section: Introductionmentioning

confidence: 99%

Influence of combined Pt and CeO₂additions on microstructure and magnetic properties in (Nd, Eu, Gd)-Ba-Cu-O

Muralidhar

Jirsa

Nariki

et al. 2001

Supercond. Sci. Technol.

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We studied the effect of the combined addition of Pt and CeO 2 on the dispersion of secondary phase Gd 2 BaCuO 5 (Gd-211) particles in melt-processed (Nd 0.33 Eu 0.33 Gd 0.33 )Ba 2 Cu 3 O y (NEG-123) by varying the CeO 2 content from 0 to 3%. Scanning electron microscopy revealed that submicrometre-sized Gd-211 particles were distributed uniformly throughout the NEG-123 matrix for additions of up to 2 mol% CeO 2 . The critical current density (J c ) increased with increasing CeO 2 content, particularly at low magnetic fields. The zero-field J c value reached its maximum of 100 kA cm −2 at 77 K for 1 mol% CeO 2 . An improvement in low-field J c was attributed to the refinement of Gd-211 particles.

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Improvement of Critical Current Densities in Bulk Superconductors of the 123-Type

Cited by 11 publications

References 7 publications

Progress in melt-processed (Nd Sm Gd)Ba₂Cu₃O_ysuperconductors

Progress in melt-processed (Nd Sm Gd)Ba₂Cu₃O_ysuperconductors

Improvement of the Magnetization of a Superconducting Bulk using an Iron Core

Influence of combined Pt and CeO₂additions on microstructure and magnetic properties in (Nd, Eu, Gd)-Ba-Cu-O

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Improvement of Critical Current Densities in Bulk Superconductors of the 123-Type

Cited by 11 publications

References 7 publications

Progress in melt-processed (Nd Sm Gd)Ba2Cu3Oysuperconductors

Progress in melt-processed (Nd Sm Gd)Ba2Cu3Oysuperconductors

Improvement of the Magnetization of a Superconducting Bulk using an Iron Core

Influence of combined Pt and CeO2additions on microstructure and magnetic properties in (Nd, Eu, Gd)-Ba-Cu-O

Contact Info

Product

Resources

About

Progress in melt-processed (Nd Sm Gd)Ba₂Cu₃O_ysuperconductors

Progress in melt-processed (Nd Sm Gd)Ba₂Cu₃O_ysuperconductors

Influence of combined Pt and CeO₂additions on microstructure and magnetic properties in (Nd, Eu, Gd)-Ba-Cu-O