Effect of Ag Addition on the Surface Topography and the Vibrational Dynamics of MgB2

Kumar, Dinesh; Muralidhar, M.; Murakami, Masato

doi:10.1007/s10948-017-4481-y

Cited by 5 publications

(3 citation statements)

References 29 publications

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“…These materials comprise dopants and additives, such as carbon, [7][8][9][10][11][12][13][14] silver, etc. [6,[15][16][17][18][19][20][21] Dopants interact with lattice, whereas additives form secondary phases, both acting then as pinning centers. These substituents were added to the solid mixture of Mg and B powders, rigorously mixed before sintering.…”

Section: Introductionmentioning

confidence: 99%

Optimization of Carbon Encapsulated Boron Doping for High‐Performance Bulk Sintered MgB₂

et al. 2020

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Carbon has been a standard doping agent in MgB 2 for long time. It, however, has also participated in a non-uniform distribution of the constituents throughout the bulk MgB 2. To address this issue, carbon encapsulated boron (CEB) was used instead of the manually added mixture of boron and carbon. The previous studies confirmed that only low concentrations of carbon in CEB were effective for synthesis of a high-performance bulk MgB 2. Here, a further step in optimization carbon content in CEB is reported. Carbon content in CEB varied as 1, 1.1, 1.35, 1.5, and 1.9 wt%. X-ray diffraction (XRD) results depict a slight shift in peaks corresponding to a-b plane, indicating carbon substitution into the lattice. High superconducting critical current density in self-field, such as 660, 550, and 435 kA cm À2 , was observed in the samples with 1.5 wt% CEB at 10, 15, and 20 K, respectively. In addition, J c of 75 kA cm À2 at 2 T and 20 K was observed in the 1.5 wt% CEB sample, which is thrice the value observed in the pure sample, with a minute tradeoff in T c (around 37.5 K). Scanning electron microscope (SEM) images reveal that small particles of size ranging from 50 to 200 nm contribute to J c improvement. Energy-dispersive X-ray (EDX) results show carbon uniformly distributed throughout the bulk.

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Section: Introductionmentioning

confidence: 99%

Optimization of Carbon Encapsulated Boron Doping for High‐Performance Bulk Sintered MgB₂

et al. 2020

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“…The E 2g mode did not shift during Ag addition, indicating no lattice substitution, the peak width was reduced with increasing Ag content. [ 39 ] Similar to Ag, Dy 2 O 3 also does not substitute in the MgB 2 lattice, but forms a secondary compound. With Dy 2 O 3 doping (0.2–2 wt%), the peak position ( ω 2 ) shifts to higher wave numbers, i.e., 540 to 580 cm −1 , intensity of PDOS increases, while the FWHM and intensity of E 2g mode decrease with increasing Dy 2 O 3 content (see.…”

Section: Resultsmentioning

confidence: 99%

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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“…The peaks shift to higher angles, indicating a carbon-doped In 2 S 3 structure as relatively high amounts of L-cysteine were used during the preparation process. The unreacted carbon species near the In 2 S 3 surfaces lead to the compression of the lattice 42 and hence causing a distortion. No characteristic peaks from impurities indicate a pure crystalline indium sulfide phase formed by the hydrothermal process.…”

Section: Xrd Patterns Of Carbon-assisted In 2 S 3 Nanoflakementioning

confidence: 99%

Photocatalytic H₂O₂ Generation over Microsphere Carbon-Assisted Hierarchical Indium Sulfide Nanoflakes via a Two-Step One-Electron Pathway

Ahmed

Abdullah

Kuo

2023

ACS Appl. Mater. Interfaces

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The increasing demand for an alternative to traditional fuel has motivated intensive research and drawn more attention. H2O2 has emerged as an alternative due to its high capabilities, relatively safer nature as a fuel, and ease of transportation. The photocatalytic method is adopted to generate H2O2 using sustainable light energy to achieve an entire green system for a completely environmentally friendly process. Herein, the synthesized microsphere carbon-assisted hierarchical two-dimensional (2D) indium sulfide (In2S3) nanoflakes have been characterized thoroughly by various techniques such as X-ray diffraction (XRD), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), diffuse reflectance spectra (DRS), photoluminescence (PL), and electron paramagnetic resonance (EPR). The photocatalytic performance of the In2S3-based photocatalysts can be promoted with the carbon layer assisting in facilitating the transfer of the photogenerated electrons and narrowing their band gaps. Optimized In2S3 successfully yielded 31.2 mM g–1 h–1 in the photocatalytic oxygen reduction reaction (ORR) process. Based on the results of different radical trapping experiments and different reaction conditions, the catalytic ORR process is proposed to be a two-step one-electron pathway.

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Effect of Ag Addition on the Surface Topography and the Vibrational Dynamics of MgB2

Cited by 5 publications

References 29 publications

Optimization of Carbon Encapsulated Boron Doping for High‐Performance Bulk Sintered MgB₂

Optimization of Carbon Encapsulated Boron Doping for High‐Performance Bulk Sintered MgB₂

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

Photocatalytic H₂O₂ Generation over Microsphere Carbon-Assisted Hierarchical Indium Sulfide Nanoflakes via a Two-Step One-Electron Pathway

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Effect of Ag Addition on the Surface Topography and the Vibrational Dynamics of MgB2

Cited by 5 publications

References 29 publications

Optimization of Carbon Encapsulated Boron Doping for High‐Performance Bulk Sintered MgB2

Optimization of Carbon Encapsulated Boron Doping for High‐Performance Bulk Sintered MgB2

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

Photocatalytic H2O2 Generation over Microsphere Carbon-Assisted Hierarchical Indium Sulfide Nanoflakes via a Two-Step One-Electron Pathway

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Resources

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Optimization of Carbon Encapsulated Boron Doping for High‐Performance Bulk Sintered MgB₂

Optimization of Carbon Encapsulated Boron Doping for High‐Performance Bulk Sintered MgB₂

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

Photocatalytic H₂O₂ Generation over Microsphere Carbon-Assisted Hierarchical Indium Sulfide Nanoflakes via a Two-Step One-Electron Pathway