Improvements of fabrication processes and enhancement of critical current densities in (Ba,K)Fe<sub>2</sub>As<sub>2</sub>HIP wires and tapes

Pyon, Sunseng; Suwa, Takahiro; Tamegai, T.; Takano, Katsutoshi; Kajitani, Hideki; Koizumi, N.; Awaji, Satoshi; Zhou, Nan; Shi, Zhixiang

doi:10.1088/1361-6668/aab8c3

Cited by 64 publications

(87 citation statements)

References 39 publications

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“…The transport J c under a high field of 100 kOe at 4.2 K for tapes of (Ba,K)Fe 2 As 2 has reached 150 kAcm −2 , which exceeds the practical level of 100 kA cm −2 [31]. In the case of tapes, transport J c is significantly enhanced by texturing of the grains due to their flat shapes helped by uniaxial pressing [26,44]. In the case of round wires, which are suitable for winding coils, texturing of the grains is difficult compared with that in tapes.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of small superconducting coils using (Ba,A)Fe₂As₂ (A: Na, K) round wires with large critical current densities

Pyon¹,

Mori²,

Tamegai³

et al. 2021

Supercond. Sci. Technol.

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We report the fabrication of small (Ba,A)Fe 2 As 2 (A: Na, K) coils using 10 m-class long round wires, fabricated by powder-in-tube (PIT) method. Coils are sintered using hot-isostatic-press (HIP) technique after glass-fiber insulations are installed. Critical current (I c ) of the whole coil using (Ba,Na)Fe 2 As 2 and (Ba,K)Fe 2 As 2 are 60 A and 66 A under the self-field, and the generated magnetic fields at the center of the coil reach 2.6 kOe and 2.5 kOe, respectively. Furthermore, the largest transport critical current density (J c ) and I c in (Ba,Na)Fe 2 As 2 wires picked up from the coil reach 54 kAcm −2 and 51.8 A at T = 4.2 K under a magnetic field of 100 kOe, respectively. This value exceeds transport J c of all previous iron-based superconducting round wires. Texturing of grains in the core of the wire due to the improvement of the wire drawing process plays a key role for the enhancement of J c .

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Section: Introductionmentioning

confidence: 99%

Fabrication of small superconducting coils using (Ba,A)Fe₂As₂ (A: Na, K) round wires with large critical current densities

Pyon¹,

Mori²,

Tamegai³

et al. 2021

Supercond. Sci. Technol.

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“…This value is approximately 35 K and it is consistent with the values reported in the literature [ 1 , 21 , 22 ]. It is worth noting the presence of a slight non-zero signal above T c in the ZFC curve as already reported in other works on iron-based systems [ 23 , 24 , 25 , 26 ], which can be limited by improving the fabrication processes [ 26 , 27 , 28 ].…”

Section: Resultsmentioning

confidence: 54%

Critical Current and Pinning Features of a CaKFe4As4 Polycrystalline Sample

et al. 2021

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We analyze the magnetic behavior of a CaKFe4As4 polycrystalline sample fabricated by a mechanochemically assisted synthesis route. By means of DC magnetization (M) measurements as a function of the temperature (T) and DC magnetic field (H) we study its critical parameters and pinning features. The critical temperature Tc has been evaluated by M(T) curves performed in Zero Field Cooling-Field Cooling conditions. These curves show the presence of a little magnetic background for temperatures above Tc, as also confirmed by the hysteresis loops M(H). Starting from the M(H) curves, the critical current density Jc of the sample has been calculated as a function of the field at different temperatures in the framework of the Bean critical state model. The Jc(H) values are in line with the ones reported in the literature for this typology of samples. By analyzing the temperature dependence of the critical current density Jc(T) at different magnetic fields, it has been found that the sample is characterized by a strong type pinning regime. This sample peculiarity can open perspectives for future improvement in the fabrication of this material.

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“…As discussed above, suppression of T c and the dose dependence of J c in 2.6-GeV U-ion or 3 MeV protonirradiated KCa 2 Fe 4 As 4 F 2 are different from those in typical IBS of (Ba,K)Fe 2 As 2 , which can be explained by considering the embedded defects in pristine KCa 2 Fe 4 As 4 F 2 . It should be emphasized that maximum J c in KCa 2 Fe 4 As 4 F 2 is larger than that in 122 compounds, which have been extensively studied as raw materials for wires and tapes for future high-field applications [44][45][46]. Fabrications of wires and tapes of KCa 2 Fe 4 As 4 F 2 are demanded.…”

Section: Resultsmentioning

confidence: 99%

Critical Current Density and Vortex Dynamics in Pristine and Irradiated KCa2Fe4As4F2

et al. 2021

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We report the critical current density (Jc) and vortex pinning properties in single crystals of a novel iron-based superconductor (IBS) KCa2Fe4As4F2 with large Jc in the pristine state, before and after introduction of artificial defects by swift-particle irradiation. The effects of 2.6 GeV U and 3 MeV proton irradiations in KCa2Fe4As4F2 single crystals on transition temperature Tc and Jc, including its dose dependence, are systematically studied. Jc~8 MA/cm2 under a self-field at 2 K in the pristine crystal is strongly enhanced up to 19.4 and 17.5 MA/cm2 by irradiation of 2.6 GeV U-ions and 3 MeV protons, respectively. Suppression of Tc and dose dependence of Jc in KCa2Fe4As4F2 is different from that in a representative IBS of (Ba,K)Fe2As2, which can be explained by considering the presence of embedded defects in pristine KCa2Fe4As4F2. The vortex dynamics in the pristine and proton irradiated KCa2Fe4As4F2 single crystals are also investigated from the analyses of the field dependence of Jc and the normalized magnetic relaxation rate. In addition to the contribution of embedded defects, weak collective pinning is considered for comprehensive analyses. Vortex dynamics in KCa2Fe4As4F2 is similar to those in (Ba,K)Fe2As2 to some extent, and different from that in anisotropic Li0.8Fe0.2OHFeSe. Large anisotropy, due to the presence of insulating blocking layers in KCa2Fe4As4F2, which leads to much lower irreversibility field (Hirr) compared with 122-type IBSs, strongly affect the vortex dynamics.

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Improvements of fabrication processes and enhancement of critical current densities in (Ba,K)Fe₂As₂HIP wires and tapes

Cited by 64 publications

References 39 publications

Fabrication of small superconducting coils using (Ba,A)Fe₂As₂ (A: Na, K) round wires with large critical current densities

Fabrication of small superconducting coils using (Ba,A)Fe₂As₂ (A: Na, K) round wires with large critical current densities

Critical Current and Pinning Features of a CaKFe4As4 Polycrystalline Sample

Critical Current Density and Vortex Dynamics in Pristine and Irradiated KCa2Fe4As4F2

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Improvements of fabrication processes and enhancement of critical current densities in (Ba,K)Fe2As2HIP wires and tapes

Cited by 64 publications

References 39 publications

Fabrication of small superconducting coils using (Ba,A)Fe2As2 (A: Na, K) round wires with large critical current densities

Fabrication of small superconducting coils using (Ba,A)Fe2As2 (A: Na, K) round wires with large critical current densities

Critical Current and Pinning Features of a CaKFe4As4 Polycrystalline Sample

Critical Current Density and Vortex Dynamics in Pristine and Irradiated KCa2Fe4As4F2

Contact Info

Product

Resources

About

Improvements of fabrication processes and enhancement of critical current densities in (Ba,K)Fe₂As₂HIP wires and tapes

Fabrication of small superconducting coils using (Ba,A)Fe₂As₂ (A: Na, K) round wires with large critical current densities

Fabrication of small superconducting coils using (Ba,A)Fe₂As₂ (A: Na, K) round wires with large critical current densities