Investigating the flux pinning in high temperature superconductors more accurately

Pu, M.H.; Feng, Yang; Zhang, P.X.; Zhou, Lian; Wang, J.X.

doi:10.1016/s0921-4534(02)02134-2

Cited by 12 publications

(12 citation statements)

References 5 publications

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“…It is quite possible that several elementary pinning mechanisms cooperate in the system simultaneously. Several modified models including the superposition of several pinning mechanisms [23], the shift of H irr [24], and the combination of both [25] were proposed to fit and interpreter the experimental data of the scaling behavior for high-T c Bi2223 superconductors and also MgB 2 superconductors. However, these models are hardly to fit the data for the 123-type high-T c superconducting melt-textured bulks because the pinning sources are much more complicated in this system.…”

Section: Resultsmentioning

confidence: 99%

Enhancement of flux pinning in GdBa2Cu3O7−y bulks prepared by nanoparticle-powder-assisted method

Cheng

Hsieh

et al. 2011

J. Mod. Transport.

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High quality GdBa 2 Cu 3 O 7-y (Gd123) textured bulks with Nd 2 BaCuO 5 (Nd211) nanoparticle precipitations have been fabricated by a nanoparticle-powders-assisted MTG (melt-textured-growth) technique. The high density nanoscale flux pinning sites were introduced into Gd123 by mixing Nd211 nanoparticle powders (about 20-50 nm) with Gd123 nano-precursors before the MTG process. Microstructural analyses reveal that a large number of Nd211 nanoparticles with a size around 50-150 nm were inserted in the Gd123 matrix, forming a kind of superconducting nanocomposites. The critical current density at 77 K is systematically increased and the flux pinning behavior is significantly improved. The scaling behavior of the flux pinning force shows a magnetic field dependent feature with a peak located at h p 0.4. This may be the fingerprint of melt-textured 123 compounds, which cannot be interpreted by the simple superposition of different types of elementary pinning sources.

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Section: Resultsmentioning

confidence: 99%

Enhancement of flux pinning in GdBa2Cu3O7−y bulks prepared by nanoparticle-powder-assisted method

Cheng

Hsieh

et al. 2011

J. Mod. Transport.

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“…Another possible contribution to the improved J c is the lower amount of porosity in the Y-doped films, while the large difference in ion size between Dy and Yb (0.042Å) compared to Dy versus Gd (0.026Å) can also have a positive effect [8], [14]. To analyse the flux pinning mechanism, we applied a modified Kramer and Dew-Hughes model [22], where the curve of f = F P /F…”

Section: Ax Pmentioning

confidence: 99%

“…J c values were calculated using the Bean model. Analysis of the pinning force was also carried out [22].…”

Section: Introductionmentioning

confidence: 99%

Superconducting Thin Films Made by Chemical Solution Deposition

Opata

Wulff

Hansen

et al. 2016

IEEE Trans. Appl. Supercond.

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“…Based on Bean model and the following equa- tion: F p = J C ·B, the F p and B irr values were deduced from the M-H curves measured at 4.2 K. Accordingly, F p /F p,max versus the reduced field (B/B irr ) is plotted in Figure 6 for Mg 1.05 B 2 sample. Regression analyses were performed based on the Dew-Hughes model as follows [20,21] :…”

Section: Condensed Matter Physicsmentioning

confidence: 99%

Fabrication of the 19-filament Fe/Cu clad MgB2 wire via in situ powder-in-tube method

Wang

et al. 2007

CHINESE SCI BULL

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Using commercial amorphous B powder (92% in purity) and Mg powder (99% in purity) as starting materials, 19-filament Fe/Cu clad MgB 2 wires were fabricated by an in situ powder-in-tube method. Heat treatment was performed at 700℃ for 1 h under an argon gas atmosphere. The influence of Mg/B ratio on the microstructure and superconducting properties of the wires was investigated. It was found that the major phases of MgB 2 wires were MgB 2 accompanied with relatively small amounts of MgO and Fe 2 B impurities. With 5% excess Mg addition, the onset T C slightly decreased. However, the transport J C at 4.2 K and 4 T reached 1.07×10 4 A·cm −2 , increasing by a factor of 1.4 compared to the stoichiometric sample. Moreover, the Mg 1.05 B 2 sample showed an improved field dependence of J C , suggesting that less voids and smaller grain size of the Mg 1.05 B 2 core lead to better grain connectivity and stronger flux pinning.in situ powder in tube method, 19-filament MgB 2 wire, Fe/Cu composite sheath, Mg/B optimization, pinning mechanismThe discovery of superconductivity in MgB 2 with T c = 39 K [1] , the highest value known for the intermetallic compounds, has attracted worldwide interest in both fundamental studies and practical applications. The advantages of MgB 2 are not only no weak links at grain boundaries, low normal state resistance and large coherence length, but also low cost and easy wire fabrication [2] . Therefore, MgB 2 has been regarded as a promising candidate for practical applications, especially in niche markets wherein the operation temperature is in the range of 20-30 K, easily reachable with cryocoolers instead of expensive liquid He. This makes it possible for MgB 2 wires to be used in a wide variety of applications, such as MRI magnet, superconducting cable and motor [3][4][5][6] .The multifilamentary wire geometry could greatly improve the properties important for applications, such as strain tolerance, flux jump stability, and AC loss [7,8] .Up to now, two technologies, known as powder-in-tube (PIT) method [9] and the continuous tube forming and filling (CTFF) process [10] , have been reported to successfully fabricate long-length multifilamentary MgB 2 strands. Since the CTFF process is too complicated and tape structure is not perfectly suitable for coil winding to generate the spatially uniform magnetic field, we attempt to fabricate the 19-filament Fe/Cu sheathed MgB 2 wire by an in situ PIT technique. In order to achieve higher J C , high purity (99.99%) amorphous boron power is a better choice [11,12] . However, the pure boron powder is currently about 10 times more expensive than the 92% boron powder. If the low-grade raw materials can be used to make MgB 2 wires, the materials cost could be decreased dramatically. Furthermore, it has been reported that the alteration in the Mg/B ratio has a significant effect on superconducting properties of MgB 2 [13,14] .In this paper, we try to fabricate 19-filament MgB 2 wires by the in situ PIT method using Fe and Cu as chemical barrier and stabili...

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Investigating the flux pinning in high temperature superconductors more accurately

Cited by 12 publications

References 5 publications

Enhancement of flux pinning in GdBa2Cu3O7−y bulks prepared by nanoparticle-powder-assisted method

Enhancement of flux pinning in GdBa2Cu3O7−y bulks prepared by nanoparticle-powder-assisted method

Superconducting Thin Films Made by Chemical Solution Deposition

Fabrication of the 19-filament Fe/Cu clad MgB2 wire via in situ powder-in-tube method

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