19 research outputs found

    Spin order dependent skyrmion stabilization in MnFeCoGe hexagonal magnets

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    Topological magnetic skyrmions in centrosymmetric systems exhibit a higher degrees of freedom in their helicity, hence possess a great potential in the advanced spintronics including skyrmion based quantum computation. However, the centrosymmetric magnets also display non-topological trivial bubbles along with the topological skyrmions. Hence it is utmost priority to investigate the impact of different magnetic ground states and their underlying interactions on the stabilization of magnetic skyrmions in cetrosymmetric magnets. Here, we present a combined theoretical and experimental study on the role of non-collinear magnetic ground state on the skyrmion stabilization in a series of exchange frustrated non-collinear ferromagnetic system MnFe1-xCoxGe. With the help of neutron diffraction (ND) and Lorentz transmission electron microscopy (LTEM) studies, we show that hexagonal skyrmions lattice emerges as a stable field driven state only when the underlying magnetic ground state is collinear with easy-axis anisotropy. In contrast, non-topological type-II bubbles are found to be stable state in the case of non-collinear magnetic ordering with partial in-plane anisotropy. Furthermore, we also find that the skyrmions transform to the non-topological bubbles when the system undergoes a spin reorientation transition from the easy-axis to easy-cone ferromagnetic phase. Our results categorically establish the significant role of in-plane magnetic moment/anisotropy that hinders the stability of skyrmion both in the case of collinear and non-collinear magnets. Thus, the present study offers a wide range of opportunities to manipulate the stability of dipolar skyrmions by changing the intrinsic characteristics of the materials.Comment: 18 pages, 4 figure

    ATHENA detector proposal - a totally hermetic electron nucleus apparatus proposed for IP6 at the Electron-Ion Collider

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    ATHENA has been designed as a general purpose detector capable of delivering the full scientific scope of the Electron-Ion Collider. Careful technology choices provide fine tracking and momentum resolution, high performance electromagnetic and hadronic calorimetry, hadron identification over a wide kinematic range, and near-complete hermeticity.This article describes the detector design and its expected performance in the most relevant physics channels. It includes an evaluation of detector technology choices, the technical challenges to realizing the detector and the R&D required to meet those challenges

    ATHENA detector proposal — a totally hermetic electron nucleus apparatus proposed for IP6 at the Electron-Ion Collider

    Get PDF
    ATHENA has been designed as a general purpose detector capable of delivering the full scientific scope of the Electron-Ion Collider. Careful technology choices provide fine tracking and momentum resolution, high performance electromagnetic and hadronic calorimetry, hadron identification over a wide kinematic range, and near-complete hermeticity. This article describes the detector design and its expected performance in the most relevant physics channels. It includes an evaluation of detector technology choices, the technical challenges to realizing the detector and the R&D required to meet those challenges

    Quantification of alloy atomic composition sites in 2D ternary MoS2(1-x)Se2x and their role in persistent photoconductivity, enhanced photoresponse and photo-electrocatalysis

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    Engineering transition metal dichalcogenides-based semiconducting two-dimensional (2D) layered materials for photo(electro)chemical (PEC) hydrogen evolution reaction (HER) by water splitting is an enduring challenge. Here, alloy-assisted photoconductivity and photoresponse from CVD-grown MoS2(1-x)Se2x (MSSE) 2D ternary atomic layered alloy-based photodetector device is presented for the realization of PEC HER. The explicit role of ‘S–Se’ and ‘Se2’ atomic alloy sites including chalcogen-induced vacancy defects on the photoconductivity/photoresponse and PEC HER performance of MSSE 2D alloy is investigated. Alloy formation, atomic site-by-site ‘Se’ composition and atomic structure are characterized using Raman/Photoluminescence (PL) spectroscopy, high-angle annular dark field (HAADF)- scanning transmission electron microscopy (STEM) extensively and supported with Auger Electron Spectroscopy (AES) mapping. Further, the local density and concentration of S–Se, Se2 atomic sites and defects were quantitatively estimated using HAADF-STEM image analysis in correlation with AES and it is found between the range of ∼15–20 % in MSSE alloy. A 10-fold high photoresponsivity in the case of MSSE concerning as-grown MS having fast photocurrent growth time and the prolonged decay time originates from the ‘Se’ and this alloy assisted states to enhance the PEC performance of MSSE alloy. The enhanced PEC HER activity of MSSE alloy was identified in terms of overpotential and current density. In addition, increased density of states as a function of ‘Se’ alloying, shifts in a p-band centre and lowers ΔGH* according to density functional theory calculations, which makes MSSE alloy an efficient HER activity. Further, the PEC stability and presence of the ‘S–Se’ and ‘Se2’ alloying and their role towards HER have been correlated by the spectral line shape analysis of PL and Raman spectra from post-PEC HER catalysts. These experimental and theoretical findings establish the role of chalcogen, and transition metal-based 2D alloy, leading to the design of new PECs of engineered 2D atomic layer interfaces

    Molecular Breeding for Incorporation of Submergence Tolerance and Durable Bacterial Blight Resistance into the Popular Rice Variety ‘Ranidhan’

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    Ranidhan is a popular late-maturing rice variety of Odisha state, India. The farmers of the state suffer heavy loss in years with flash floods as the variety is sensitive to submergence. Bacterial blight (BB) disease is a major yield-limiting factor, and the variety is susceptible to the disease. BB resistance genes Xa21, xa13, and xa5, along with the Sub1 QTL, for submergence stress tolerance were transferred into the variety using marker-assisted backcross breeding approach. Foreground selection using direct and closely linked markers detected the progenies carrying all four target genes in the BC1F1, BC2F1, and BC3F1 generations, and the positive progenies carrying these genes with maximum similarity to the recipient parent, Ranidhan, were backcrossed into each segregating generation. Foreground selection in the BC1F1 generation progenies detected all target genes in 11 progenies. The progeny carrying all target genes and similar to the recipient parent in terms of phenotype was backcrossed, and a total of 321 BC2F1 seeds were produced. Ten progenies carried all target genes/QTL in the BC2F1 generation. Screening of the BC3F1 progenies using markers detected 12 plants carrying the target genes. A total of 1270 BC3F2 seeds were obtained from the best BC3F1 progeny. Foreground selection in the BC3F2 progenies detected four plants carrying the target genes in the homozygous condition. The bioassay of the pyramided lines conferred very high levels of resistance to the predominant isolates of bacterial blight pathogen. These BB pyramided lines were submergence-tolerant and similar to Ranidhan in 13 agro-morphologic and grain quality traits; hence, they are likely to be adopted by farmers

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    Not AvailableRanidhan is a popular late-maturing rice variety of Odisha state, India. The farmers of the state suffer heavy loss in years with flash floods as the variety is sensitive to submergence. Bacterial blight (BB) disease is a major yield-limiting factor, and the variety is susceptible to the disease. BB resistance genesXa21, xa13, and xa5, along with the Sub1 QTL, for submergence stress tolerance were transferred into the variety using marker-assisted backcross breeding approach. Foreground selection using direct and closely linked markers detected the progenies carrying all four target genes in the BC1F1, BC2F1, and BC3F1 generations, and the positive progenies carrying these genes with maximum similarity to the recipient parent, Ranidhan, were backcrossed into each segregating generation. Foreground selection in the BC1F1 generation progenies detected all target genes in 11 progenies. The progeny carrying all target genes and similar to the recipient parent in terms of phenotype was backcrossed, and a total of 321 BC2F1 seeds were produced. Ten progenies carried all target genes/QTL in the BC2F1 generation. Screening of the BC3F1 progenies using markers detected 12 plants carrying the target genes. A total of 1270 BC3F2 seeds were obtained from the best BC3F1 progeny. Foreground selection in the BC3F2 progenies detected four plants carrying the target genes in the homozygous condition. The bioassay of the pyramided lines conferred very high levels of resistance to the predominant isolates of bacterial blight pathogen. These BB pyramided lines were submergence-tolerant and similar to Ranidhan in 13 agro-morphologic and grain quality traits; hence, they are likely to be adopted by farmers.Not Availabl

    Covalently Connected Carbon Nanotubes as Electrocatalysts for Hydrogen Evolution Reaction through Band Engineering

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    Controlled assembly of mesoscopic structures can bring interesting phenomena because of their interfaces. Here, carbon nanotubes (CNTs) are cross-coupled via a C–C bonding through Suzuki reaction resulting in three-dimensional (3D) CNT sponges, and these 3D CNTs are studied for their efficacy toward the electrocatalytic hydrogen evolution reaction (HER) in acidic mediumone of the promising methods for the production of a renewable energy source, hydrogen. Both single and multiwall CNTs (SWCNTs and MWCNTs) are studied for the development of 3DSWCNTs and 3DMWCNTs, and these 3D CNTs are found to be HER active with small reaction onset potentials and low charge-transfer resistances unlike their uncoupled counterparts. First-principle density functional calculations show that the combination of electron acceptor and donor bonded to the CNT network can provide a unique band structure modulation in the system facilitating the HER reaction. This study can provide possibilities for band engineering of CNTs via functionalization and cross-coupling reactions

    Molecular Breeding for Incorporation of Submergence Tolerance and Durable Bacterial Blight Resistance into the Popular Rice Variety ‘Ranidhan’

    Full text link
    Ranidhan is a popular late-maturing rice variety of Odisha state, India. The farmers of the state suffer heavy loss in years with flash floods as the variety is sensitive to submergence. Bacterial blight (BB) disease is a major yield-limiting factor, and the variety is susceptible to the disease. BB resistance genes Xa21, xa13, and xa5, along with the Sub1 QTL, for submergence stress tolerance were transferred into the variety using marker-assisted backcross breeding approach. Foreground selection using direct and closely linked markers detected the progenies carrying all four target genes in the BC1F1, BC2F1, and BC3F1 generations, and the positive progenies carrying these genes with maximum similarity to the recipient parent, Ranidhan, were backcrossed into each segregating generation. Foreground selection in the BC1F1 generation progenies detected all target genes in 11 progenies. The progeny carrying all target genes and similar to the recipient parent in terms of phenotype was backcrossed, and a total of 321 BC2F1 seeds were produced. Ten progenies carried all target genes/QTL in the BC2F1 generation. Screening of the BC3F1 progenies using markers detected 12 plants carrying the target genes. A total of 1270 BC3F2 seeds were obtained from the best BC3F1 progeny. Foreground selection in the BC3F2 progenies detected four plants carrying the target genes in the homozygous condition. The bioassay of the pyramided lines conferred very high levels of resistance to the predominant isolates of bacterial blight pathogen. These BB pyramided lines were submergence-tolerant and similar to Ranidhan in 13 agro-morphologic and grain quality traits; hence, they are likely to be adopted by farmers
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