Microstructural and magnetic analysis of a superconducting foam and comparison with IG-processed bulk samples

Koblischka-Veneva, Anjela; Koblischka, Michael Rudolf; Ide, N; Inoue, Kiyoshi; Muralidhar, M.; Hauet, Thomas; Murakami, Masato

doi:10.1088/1742-6596/695/1/012002

Cited by 11 publications

(15 citation statements)

References 14 publications

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“…The microstructure investigations were performed using scanning electron microscopy (SEM), atomic force microscopy (AFM), and electron backscatter diffraction (EBSD). More details about these measurements can be found in previous publications [27,28].…”

Section: Such a 211 Foam Is Presented Inmentioning

confidence: 99%

Superconducting YBCO Foams as Trapped Field Magnets

Koblischka¹,

Naik²,

Koblischka-Veneva³

et al. 2019

Preprint

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Superconducting foams of YBa$_2$Cu$_3$O$_y$ (YBCO) are proposed as trapped field magnets or supermagnets. The foams with an open-porous structure are light-weight, mechanically strong and can be prepared in large sample sizes. The trapped field distributions were measured using a scanning Hall probe on various sides of an YBCO foam sample after field-cooling in a magnetic field of 0.5 T produced by a square Nd-Fe-B permanent magnet. The maximum trapped field (TF) measured is about 400 G (77 K) at the bottom of the sample. Several details of the TF distribution, the current flow and possible applicatons of such superconducting foam samples in space applications, e.g., as active elements in flux-pinning docking interfaces (FPDI) or as portable strong magnets to collect debris in space, are outlined.

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Section: Such a 211 Foam Is Presented Inmentioning

confidence: 99%

Superconducting YBCO Foams as Trapped Field Magnets

Koblischka¹,

Naik²,

Koblischka-Veneva³

et al. 2019

Preprint

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“…Here it is important to point out that the foam samples share this behavior with the melt-textured, IG processed YBCO bulks as discussed in Ref. [10]. This demonstrates that the specific microstructure with embedded, tiny 211 particles which both materials have in common, is responsible for this peak position and the resulting shape of the pinning function.…”

Section: Resultsmentioning

confidence: 52%

“…the variation of the microstructure and of the linked superconducting properties throughout the foam structure, which was not addressed in previous works [8]- [10]. This information is a valuable input for modelling of the foam structure, which can make use of attempts already existing in the literature on open-cell polyurethane and metal foams [11], [12].…”

mentioning

confidence: 99%

Current Flow and Flux Pinning Properties of YBCO Foam Struts

Koblischka

Koblischka-Veneva

Berger

et al. 2019

IEEE Trans. Appl. Supercond.

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The current flow and the flux pinning properties on struts of superconducting YBa2Cu3Ox (YBCO) foams are analyzed in detail in the temperature range 60 K ≤ T ≤ Tc. For this purpose, magnetization loops were measured on foam struts taken from various positions of a 5 × 2 × 2 cm 3 large foam sample prepared at RWTH Aachen. From these data, the critical current densities, jc, and the flux pinning forces, Fp = jc × B, were calculated and pinning force scaling diagrams Fp/Fp,max vs. h = Ha/Hirr were established. The scaling in the temperature range 60 K < T < 90 K was found to be well developed for all samples with peak positions, h0, above 0.4, which is an indication of δTc-pinning. The shape of the pinning functions is found to be completely different from all other high-Tc materials and varies only slightly with position. This specific dome-shape cannot be described by an addition of several pinning functions, and the parameters p and q do not fit to the description of Dew-Hughes. Therefore, we employ Kramer plots to obtain more information on the flux pinning mechanism. Index Terms-Foam, YBCO, critical currents, flux pinning, scaling. I. INTRODUCTION S UPERCONDUCTING foams are an interesting class of high-T c materials for various applications due to several advantages as compared to conventional bulk samples [1]-[5]. These advantages include facile oxygenation and effective cooling processes, scalability, light weight of the samples, easy shaping and reduced material costs [6], [7]. The superconducting foams may be useful for a variety of applications, starting from fault-current limiters to trapped field magnets and elements in electric motors and generators, where the reduced weight may play an important role. However, the high-T c superconducting foam samples prepared up to now pose many new questions concerning the current flow in such a 3D material and the corresponding flux pinning properties, which are essential to be answered for future applications of these materials. One important issue is the detailed understanding of Manuscript received xx.xx.xxxx. This work is a part of the SUPERFOAM international project funded by ANR and DFG under the references ANR-17-CE05-0030 and DFG-ANR Ko2323-10.

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“…The microstructure of both types of samples is, however, similar to each other, and both samples share the presence of many, very small 211 particles as discussed in Ref. [18]. These particles provide additional flux pinning, and the pinning force scaling of these two sample types exhibit peak positions of ∼0.5 and a completely different shape of the resulting pinning function which resembles a dome-shape.…”

Section: Resultsmentioning

confidence: 59%

“…1 × 1 × 0.5 mm 3 ). For the RE-123 materials, we have chosen a bulk YBCO sample [15] prepared via the infiltration-growth (IG) process [16], [17], a strut of a YBCO foam due to its outstanding pinning properties [5], [18], [19], and a (Nd,Eu,Gd)-123 (NEG) melt-textured bulk with TiO 2 -nanoparticles enhancing the flux pinning properties [20], [21]. For MgB 2 , we selected a sample prepared via solid-state sintering [6], a spark-plasma sintered sample [7], [22] and a sintered sample with added carbon-encapsulated boron [23], [24].…”

mentioning

confidence: 99%

Comparison of Temperature and Field Dependencies of the Critical Current Densities of Bulk YBCO, MgB<inline-formula> <tex-math notation="LaTeX">$_2$</tex-math> </inline-formula>, and Iron-Based Superconductors

Koblischka-Veneva

Koblischka

Berger

et al. 2019

IEEE Trans. Appl. Supercond.

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et al.. Comparison of the temperature and field dependencies of the critical current densities of bulk YBCO, MgB2 and iron-based superconductors. IEEE Transactions on Applied Superconductivity,Abstract-We compare the temperature and field dependence of the critical current densities of high-Tc superconductor materials intended for various bulk applications like trapped-field magnets. This comprises bulk samples of YBa2Cu3Ox (YBCO), MgB2 and iron-based materials, including also various versions of the YBCO compound like melt-textured ones, infiltration-growth processed ones, and YBCO foams. Critical current densities and flux pinning forces were obtained from magnetization loops measured using Quantum Design SQUID and PPMS systems with applied magnetic fields of up to ±9 T. The obtained data are compared to each other with respect of the optimal cooling temperature possible using modern cryocoolers. Furthermore, we plot the temperature dependencies of the critical current densities versus the normalized temperature t = T /Tc. This enables a direct judgement of the performance of the material in the trapped field applications.

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Microstructural and magnetic analysis of a superconducting foam and comparison with IG-processed bulk samples

Cited by 11 publications

References 14 publications

Superconducting YBCO Foams as Trapped Field Magnets

Superconducting YBCO Foams as Trapped Field Magnets

Current Flow and Flux Pinning Properties of YBCO Foam Struts

Comparison of Temperature and Field Dependencies of the Critical Current Densities of Bulk YBCO, MgB<inline-formula> <tex-math notation="LaTeX">$_2$</tex-math> </inline-formula>, and Iron-Based Superconductors

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