Pinning behavior in bulk MgB2 prepared using boron powder refined via high-energy ultra-sonication

Arvapalli, Sai Srikanth; Muralidhar, M.; Jirsa, M.; Sakai, Naomichi; Murakami, Masato

doi:10.1007/s10948-021-05885-z

Cited by 8 publications

(5 citation statements)

References 27 publications

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“…For example, carbon doping shifts the peak to the right, while grain refinement resulting in more grain boundaries tends to shift the peak to the left. [ 43,44 ] In the present study, we can observe that the peak position shifted from 0.19 for 0 wt% Dy 2 O 3 to 0.23 for 1 wt% Dy 2 O 3 (see Figure ). The shift towards higher values indicates certain high‐field pinning in addition to conventional grain boundary pinning.…”

Section: Resultssupporting

confidence: 65%

Enhancing Critical Current Density of Bulk MgB₂ via Nanoscale Boron and Dy₂O₃ Doping

Muralidhar¹,

Kitamoto²,

Arvapalli³

et al. 2022

Adv Eng Mater

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Moderate critical current density (Jc) has been a long‐lasting problem in bulk MgB2 superconductors. We show a certain increment in Jc of bulk MgB2 via the use of amorphous boron precursor together with Dy2O3 doping. Dy2O3 dopant concentration varies from 0 to 2 wt%. X‐Ray diffraction (XRD) shows the formation of DyB4 particles. The critical temperature (Tc) is not affected by Dy2O3 doping and stands close to 38 K, showing that there is no Dy interaction with the MgB2 lattice. Microstructural studies show nanometer‐sized MgB2 grains. A high self‐field Jc of around 380 kA cm−2 is achieved at 20 K within the Dy2O3 doping range of 0.5–1.5 wt%. At around 1 wt% Dy2O3 doping an improved high‐field performance, 90 kA cm−2 at 2 T, 20 K, is observed. In the flux pinning diagram, 1 wt% Dy2O3 doping caused a peak shift from 0.19 (0 wt%) to 0.23. This indicates secondary pinning by DyB4 and lattice strains. Raman studies show the increase in the phonon density of states (PDOS) with increasing Dy2O3 doping.

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Section: Resultssupporting

confidence: 65%

Enhancing Critical Current Density of Bulk MgB₂ via Nanoscale Boron and Dy₂O₃ Doping

Muralidhar¹,

Kitamoto²,

Arvapalli³

et al. 2022

Adv Eng Mater

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“…This method was applied for the fabrication of YBCO bulk single grains by top-seeded IG process, and improvement of the superconducting properties were achieved. Later, this method was applied to other superconducting compounds such as MgB 2 , where it successfully improved the superconducting properties [22,23]. This clearly shows the efficiency of the present method, which is a general one and can be applied to various materials and methods to improve the physical and functional properties.…”

Section: Introductionmentioning

confidence: 59%

Investigation of high-energy ultrasonication of RE₂BaCuO₅(RE = Y, Gd) on the growth and superconducting properties of REBa₂Cu₃O_7−δtop-seeded melt textured bulks

Naik¹,

Hagiwara²,

Ishibashi³

et al. 2022

Supercond. Sci. Technol.

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Recently, the improvement of flux pinning performance of REBa2Cu3O7-δ (REBCO) bulk was achieved employing high energy ultrasonic irradiation (up to 300 W and 60 min) prior to the infiltration-growth process. Here, we demonstrate that higher ultrasonic power and shorter duration treatment (450 W for 30 min) of the RE2BaCuO5 (RE211, RE = Y, Gd) powder produces individual, nanometer-sized and surface damaged ultrasonically pre-treated RE211 particles (RE211Ultra). We study the growth of YBCO and GdBCO systems via top-seeded melt-growth (TSMG) method and with the addition of 30 mol% of RE211Ultra, which were pre-treated by high-energy ultrasonication and compared with the conventional method. Isothermal growth experiments clarified that the addition of RE211Ultra particles enables faster and more effective crystal growth via an improved peritectic reaction due to their size in the nanometer range and due to the presences of sharp edges, which is crucial for growing large, single grain bulks of REBCO. Microstructural investigations by scanning electron microscopy indicated the presence of 2 differently sized RE211 inclusions within the bulk GdBCO and YBCO superconductors. All samples showed an onset of superconductivity at ~92 K or above. Utilizing the effective growth temperature window and the addition of RE211Ultra, single grain bulks of GdBCO and YBCO were fabricated by the slow-cooling method. The field dependence critical current density (Jc) of the bulk samples using RE211Ultra were found to exhibit superior performance over the standard GdBCO/ YBCO samples due to significant changes of sample growth and of their microstructures. Here, we discuss various factors affecting the addition of RE211Ultra on the development of the microstructure, the growth of bulk, single grain materials and further, the superconducting properties of different REBCO superconductors.

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“…A comprehensive comparison is shown in table 1. Further, one should also take into consideration, the possible pinning from special Mg-B-O phases forming on the pore walls of the bulk MgB2 matrix, which we have previously observed [29]. To establish a profound relationship we are further working with solvents with different viscosities.…”

Section: Resultsmentioning

confidence: 99%

Effect of boron precursor ultra-sonicated in hexane medium on the critical current density of sintered bulk MgB₂

Arvapalli

Jirsa

Murakami

et al. 2022

J. Phys.: Conf. Ser.

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The large coherence length of MgB2 material allows large defects such as grain boundaries to act as strong pinning centres. As an alternative to the high-cost commercial nano precursors, we used a novel ultra-sonication technique to refine a cheap rough boron precursor and avoid the use of the expensive commercial nano amorphous boron powder. Recent novel low-cost ultra-sonication technique proved to improve the critical current density, J c, of MgB2. Here, we discuss the consequences of ultra-sonication duration in hexane medium on the boron precursor as well as the superconducting properties of MgB2 bulks. XRD revealed small peaks corresponding to unreacted Mg. First derivative of susceptibility was plotted as a function of temperature to explain the Tc,onset and ΔTc. J c was found to grow if the MgB2 bulk was prepared of boron ultra-sonicated for up to 30 minutes and then reduced with further boron ultra-sonication (60 minutes). SEM micrographs showed that boron powder subjected to longer ultra-sonication resulted in agglomeration of broken boron particles, forming large MgB2 grains. Based on the comparison of superconducting properties with previous results, we speculate that viscosity of the ultra-sonication medium might have a crucial role in the refinement of boron precursor powder.

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Pinning behavior in bulk MgB2 prepared using boron powder refined via high-energy ultra-sonication

Cited by 8 publications

References 27 publications

Enhancing Critical Current Density of Bulk MgB₂ via Nanoscale Boron and Dy₂O₃ Doping

Enhancing Critical Current Density of Bulk MgB₂ via Nanoscale Boron and Dy₂O₃ Doping

Investigation of high-energy ultrasonication of RE₂BaCuO₅(RE = Y, Gd) on the growth and superconducting properties of REBa₂Cu₃O_7−δtop-seeded melt textured bulks

Effect of boron precursor ultra-sonicated in hexane medium on the critical current density of sintered bulk MgB₂

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Pinning behavior in bulk MgB2 prepared using boron powder refined via high-energy ultra-sonication

Cited by 8 publications

References 27 publications

Enhancing Critical Current Density of Bulk MgB2 via Nanoscale Boron and Dy2O3 Doping

Enhancing Critical Current Density of Bulk MgB2 via Nanoscale Boron and Dy2O3 Doping

Investigation of high-energy ultrasonication of RE2BaCuO5(RE = Y, Gd) on the growth and superconducting properties of REBa2Cu3O7−δtop-seeded melt textured bulks

Effect of boron precursor ultra-sonicated in hexane medium on the critical current density of sintered bulk MgB2

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Enhancing Critical Current Density of Bulk MgB₂ via Nanoscale Boron and Dy₂O₃ Doping

Enhancing Critical Current Density of Bulk MgB₂ via Nanoscale Boron and Dy₂O₃ Doping

Investigation of high-energy ultrasonication of RE₂BaCuO₅(RE = Y, Gd) on the growth and superconducting properties of REBa₂Cu₃O_7−δtop-seeded melt textured bulks

Effect of boron precursor ultra-sonicated in hexane medium on the critical current density of sintered bulk MgB₂