Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Naeem, M.*; Ma, Y.*; Tian, J.*; Kong, H.*; Romero-Resendiz, L.*; Fan, Z.*; Jiang, F.*; Gong, W.; Harjo, S.; Wu, Z.*; et al.
Materials Science & Engineering A, 924, p.147819_1 - 147819_10, 2025/02
被引用回数：0 パーセンタイル：0.00(Nanoscience & Nanotechnology)Face-centered cubic (fcc) medium-/high-entropy alloys (M/HEAs) typically enhance strength and ductility at cryogenic temperatures via stacking faults, twinning, or martensitic transformation. However, in-situ neutron diffraction on VCoNi MEA at 15 K reveals that strain hardening is driven solely by rapid dislocation accumulation, without these mechanisms. This results in increased yield strength, strain hardening, and fracture strain. The behavior, explained by the Orowan equation, challenges conventional views on cryogenic strengthening in fcc M/HEAs and highlights the role of dislocation-mediated plasticity at low temperatures.
Xu, J.*; Lang, P.*; Liang, S.*; Zhang, J.*; Fei, Y.*; Wang, Y.*; Gao, D.*; 服部 高典; 阿部 淳*; Dong, X.*; et al.
Journal of Physical Chemistry Letters (Internet), p.2445 - 2451, 2025/00
被引用回数：0 パーセンタイル：0.00(Chemistry, Physical)アルダー-エン反応は、アルケンとアリル水素との化学反応であり、C-C結合を構築する効率的な方法である。従来、この反応には触媒、高温、あるいは光触媒が必要であった。本研究では、触媒を用いずに室温下で加圧することで成功した1-ヘキセンのアルダー-エン反応を報告する。1-ヘキセンは4.3GPaで結晶化し、18GPaで重合してオレフィンを形成する。ガスクロマトグラフィー-質量分析法により、1-ヘキセンが高圧下でのアルダー-エン反応により二量体を生成することを発見した。その場中性子回折から、この反応過程はトポケミカル則に従わないことがわかった。理論計算により、1つのC-H 
結合と2つのアルケン
結合を含む6員環遷移状態が示され、そのエネルギーは20GPaまで圧縮すると明らかに減少した。本研究は、触媒を用いずに室温でアルダー-エン反応を実現する新規かつ有望な方法を提供し、この重要な反応の応用を拡大するものである。
neutron diffractionNaeem, M.*; Ma, Y.*; Knowles, A. J.*; Gong, W.; Harjo, S.; Wang, X.-L.*; Romero Resendiz, L.*; 他6名*
Materials Science & Engineering A, 916, p.147374_1 - 147374_8, 2024/11
被引用回数：2 パーセンタイル：67.89(Nanoscience & Nanotechnology)Heterostructured materials (HSMs) improve the strength-ductility trade-off of alloys, but their cryogenic performance under real-time deformation is unclear. We studied heterostructured CrCoNi medium-entropy alloy via neutron diffraction at 77 K and 293 K. A significant mechanical mismatch between fine and coarse grains led to an exceptional yield strength of 918 MPa at 293 K, increasing to 1244 MPa at 77 K with a uniform elongation of 34%. This strength-ductility synergy at 77 K is attributed to high dislocation pile-up density, increased planar faults, and martensitic transformation. Compared to homogeneous alloys, HSMs show promise for enhancing cryogenic mechanical performance in medium-/high-entropy alloys.
Zhu, L.*; He, H.*; Naeem, M.*; Sun, X.*; Qi, J.*; Liu, P.*; Harjo, S.; 中島 健次; Li, B.*; Wang, X.-L.*
Physical Review Letters, 133(12), p.126701_1 - 126701_6, 2024/09
被引用回数：1 パーセンタイル：53.15(Physics, Multidisciplinary)It has long been suspected that magnetism could play a vital role in the phase stability of multi- component high-entropy alloys. However, the nature of the magnetic order, if any, has remained elusive. Here, by using elastic and inelastic neutron scattering, we demonstrate evidence of antiferromagnetic order below 
80 K and strong spin fluctuations persisting to room temperature in a single-phase face-centered cubic (fcc) CrMnFeCoNi high-entropy alloy. Despite the chemical complexity, the magnetic structure in CrMnFeCoNi can be described as 
-Mn-like, with the magnetic moments confined in alternating (001) planes and pointing toward the 
111
direction. Combined with first-principles calculation results, it is shown that the antiferromagnetic order and spin fluctuations help stabilized the fcc phase in CrMnFeCoNi high-entropy alloy.
Wang, S.*; Wang, J.*; Zhang, S.*; Wei, D.*; Chen, Y.*; Rong, X.*; Gong, W.; Harjo, S.; Liu, X.*; Jiao, Z.*; et al.
Journal of Materials Science & Technology, 185, p.245 - 258, 2024/06
被引用回数：13 パーセンタイル：98.32(Materials Science, Multidisciplinary)Nanoprecipitates and nanoscale retained austenite (RA) with suitable stability play crucial roles in determining the yield strength (YS) and ductility of ultrahigh strength steels (UHSSs). However, owing to the kinetics incompatibility between nanoprecipitation and austenite reversion, it is highly challenging to simultaneously introduce high-density nanoprecipitates and optimized RA in UHSSs. In this work, through the combination of austenite reversion treatment (ART) and subsequent flash austenitizing (FA), nanoscale chemical heterogeneity was successfully introduced into a low-cost UHSS prior to the aging process. This chemical heterogeneity involved the enrichment of Mn and Ni in the austenite phase. The resulting UHSS exhibited dual-nanoprecipitation of Ni(Al,Mn) and (Mo,Cr)
C and nanoscale austenite stabilized via Mn and Ni enrichment. The hard martensitic matrix strengthened by high-density dual-nanoprecipitates constrains the plastic deformation of soft RA with a relatively low fraction, and the presence of relatively stable nanoscale RA with adequate Mn and Ni enrichment leads to a marginal loss in YS but keeps a persistent transformation-induced plasticity (TRIP) effect. As a result, the newly-developed UHSS exhibits an ultrahigh YS of 1.7 GPa, an ultimate tensile strength (UTS) of 1.8 GPa, a large uniform elongation (UE) of 8.5 percent, and a total elongation (TE) of 13 percent. The strategy of presetting chemical heterogeneity to introduce proper metastable phases before aging can be extended to other UHSSs and precipitation-hardened alloys.
水野 るり恵*; 新倉 潤*; 齋藤 岳志*; 松崎 禎市郎*; 櫻井 博儀*; Amato, A.*; 浅利 駿介*; Biswas, S.*; Chiu, I.-H.; Gianluca, J.*; et al.
Nuclear Instruments and Methods in Physics Research A, 1060, p.169029_1 - 169029_14, 2024/03
被引用回数：2 パーセンタイル：28.72(Instruments & Instrumentation)We have developed a photon detection system for muonic X-ray spectroscopy. The detector system consists of high-purity germanium detectors with BGO Compton suppressors. The signals from the detectors are readout with a digital acquisition system. The absolute energy accuracy, energy and timing resolutions, photo-peak efficiency, the performance of the Compton suppressor, and high count rate durability are studied with standard -ray sources and in-beam experiment using 
Al(
)
Si resonance reaction. The detection system was demonstrated at Paul Scherrer Institute. A calibration method for a photon detector at a muon facility using muonic X-rays of 
Au and 
Bi is proposed.
Linh, B. D.*; Corsi, A.*; Gillibert, A.*; Obertelli, A.*; Doornenbal, P.*; Barbieri, C.*; Duguet, T.*; G
mez-Ramos, M.*; Holt, J. D.*; Hu, B. S.*; et al.
Physical Review C, 109(3), p.034312_1 - 034312_15, 2024/03
被引用回数：1 パーセンタイル：63.95(Physics, Nuclear)理化学研究所RIビームファクトリーにて中性子過剰核
Arビームからの1中性子ノックアウト反応実験を行い、
Arのエネルギー準位および分光学的因子を導出した。特に、第一励起状態の
への分光学的因子が大きいことから、始状態のArの基底状態において中性子が
軌道を多く占めていることがわかった。これは、中性子数32がよい魔法数として知られる
Caとは異なった性質であり、カルシウムからアルゴンへと陽子が2個減ることで閉殻構造が大きく崩れることが明らかになった。
SnHuang, Z.*; Wang, W.*; Ye, H.*; Bao, S.*; Shangguan, Y.*; Liao, J.*; Cao, S.*; 梶本 亮一; 池内 和彦*; Deng, G.*; et al.
Physical Review B, 109(1), p.014434_1 - 014434_9, 2024/01
被引用回数：2 パーセンタイル：46.22(Materials Science, Multidisciplinary)TbMnSn is a correlated topological magnet with a Mn-based kagome lattice, in which a Chern gap opens at the Dirac point at low temperatures. The magnetic moment direction of the ferrimagnetic order changes from in the kagome plane to the out-of-plane upon cooling, which is essential for generating the Chern gap, but the underlying mechanism for the spin reorientation remains elusive. Here, we investigate the spin-reorientation transition in TbMnSn using neutron scattering. We provide direct evidence for the spin-reorientation transition and unveil the coexistence of two Tb modes at 200 K. To account for these results, we put forward a model based on SU(N) spin-wave theory, in which there is a temperature evolution of the ground state Tb 
orbitals, driven by the crystalline electric field, single-ion anisotropy, and exchange interactions between Tb and Mn ions. Our findings shed light on the complex magnetism of TbMnSn, despite its relatively simple ground state magnetic structure, and provide insights into the mechanisms for tuning magnetic topological materials.
Zhang, A.*; Deng, K.*; Sheng, J.*; Liu, P.*; Kumar, S.*; 島田 賢也*; Jiang, Z.*; Liu, Z.*; Shen, D.*; Li, J.*; et al.
Chinese Physics Letters, 40(12), p.126101_1 - 126101_8, 2023/12
被引用回数：9 パーセンタイル：81.90(Physics, Multidisciplinary)In a Dirac semimetal, the massless Dirac fermion has zero chirality, leading to surface states connected adiabatically to a topologically trivial surface state as well as vanishing anomalous Hall effect. Recently, itis predicted that in the nonrelativistic limit of certain collinear antiferromagnets, there exists a type of chiral "Dirac-like" fermion, whose dispersion manifests four-fold degenerate crossing points formed by spin-degenerate linear bands, with topologically protected Fermi arcs. Here, by combining with neutron diffraction and first-principles calculations, we suggest a multidomain collinear antiferromagnetic configuration, rendering the existence of the Fermi-arc surface states induced by chiral Dirac-like fermions.
Ratliff, H.; McGirl, N. A.*; Beach, M. R.*; Castellanos, L. A.*; Clowdsley, M. S.*; Heilbronn, L. H.*; LaTessa, C.*; Norbury, J. W.*; Rusek, A.*; Sivertz, M.*; et al.
Nuclear Instruments and Methods in Physics Research B, 544, p.165121_1 - 165121_15, 2023/11
被引用回数：0 パーセンタイル：0.00(Instruments & Instrumentation)Experiments emulating the deep-space radiation environment within an enclosed spacecraft were conducted at the NASA Space Radiation Laboratory; this was achieved by bombarding various combinations of two consecutive thick targets with Galactic Cosmic Ray-like particle beams. While all secondary particles generated in the first of these two targets could be characterized using time-of-flight techniques, characterization of the neutrons produced in the second target, emulating the "back wall" of a spacecraft, required the development and implementation of deconvolution techniques. This work covers this methodology, its validation, and the systematic results present within this benchmark dataset of neutron yields from the secondary target.
Be ground-state molecular structure using Be(
)
He triple differential reaction cross-section measurementsLi, P. J.*; Beaumel, D.*; Lee, J.*; Assi
, M.*; Chen, S.*; Franchoo, S.*; Gibelin, J.*; Hammache, F.*; Harada, T.*; 延与 佳子*; et al.
Physical Review Letters, 131(21), p.212501_1 - 212501_7, 2023/11
被引用回数：18 パーセンタイル：91.30(Physics, Multidisciplinary)Beのクラスター構造を()反応を用いて調査した。三重微分断面積が実験的に測定され、Tohsaki-Horiuchi-Schuck-R
pke波動関数の方法や反対称化分子動力学を用いた歪曲波インパルス近似計算と比較した。実験データと理論計算の顕著な一致が確認され、Beの比較的コンパクトな分子状態を確認した。
Lyons, T. P.*; Puebla, J.*; 山本 慧; Deacon, R. S.*; Hwang, Y.*; 石橋 幸治*; 前川 禎通*; 大谷 義近*
Physical Review Letters, 131(19), p.196701_1 - 196701_6, 2023/11
被引用回数：14 パーセンタイル：86.35(Physics, Multidisciplinary)Harnessing the causal relationships between mechanical and magnetic properties of van der Waals materials presents a wealth of untapped opportunity for scientific and technological advancement, from precision sensing to novel memories. This can, however, only be exploited if the means exist to efficiently interface with the magnetoelastic interaction. Here, we demonstrate acoustically-driven spin-wave resonance in a crystalline antiferromagnet, chromium trichloride, via surface acoustic wave irradiation. The resulting magnon-phonon coupling is found to depend strongly on sample temperature and external magnetic field orientation, and displays a high sensitivity to extremely weak magnetic anisotropy fields in the few mT range. Our work demonstrates a natural pairing between power-efficient strain-wave technology and the excellent mechanical properties of van der Waals materials, representing a foothold towards widespread future adoption of dynamic magneto-acoustics.
民井 淳*; Pellegri, L.*; Sderstrm, P.-A.*; Allard, D.*; Goriely, S.*; 稲倉 恒法*; Khan, E.*; 木戸 英治*; 木村 真明*; Litvinova, E.*; et al.
European Physical Journal A, 59(9), p.208_1 - 208_21, 2023/09
被引用回数：5 パーセンタイル：77.95(Physics, Nuclear)光核反応は原子核構造の観点からも応用の観点からも重要であるにも関わらず、その反応断面積は未だに不定性が大きい。近年、超高エネルギー宇宙線の起源を探るために、鉄よりも軽い原子核の光核反応断面積を正確に知る必要が指摘されている。この状況を打破するため、原子核物理の実験、理論、宇宙物理の共同研究となるPANDORAプロジェクトが始まった。本論文はその計画の概要をまとめたものである。原子核実験ではRCNP、iThembaによる仮想光子実験とELI-NPによる実光子実験などが計画されている。原子核理論では、乱雑位相近似計算、相対論的平均場理論、反対称化分子動力学、大規模殻模型計算などが計画されている。これらで得られた信頼性の高い光核反応データベースと宇宙線伝搬コードを組み合わせ、超高エネルギー宇宙線の起源の解明に挑む。
Bao, S.*; Gu, Z.-L.*; Shangguan, Y.*; Huang, Z.*; Liao, J.*; Zhao, X.*; Zhang, B.*; Dong, Z.-Y.*; Wang, W.*; 梶本 亮一; et al.
Nature Communications (Internet), 14, p.6093_1 - 6093_9, 2023/09
被引用回数：17 パーセンタイル：93.61(Multidisciplinary Sciences)Magnon polarons are novel elementary excitations possessing hybrid magnonic and phononic signatures, and are responsible for many exotic spintronic and magnonic phenomena. Despite long-term sustained experimental efforts in chasing for magnon polarons, direct spectroscopic evidence of their existence is hardly observed. Here, we report the direct observation of magnon polarons using neutron spectroscopy on a multiferroic FeMo
O
possessing strong magnon-phonon coupling. Specifically, below the magnetic ordering temperature, a gap opens at the nominal intersection of the original magnon and phonon bands, leading to two separated magnon-polaron bands. Each of the bands undergoes mixing, interconverting and reversing between its magnonic and phononic components. We attribute the formation of magnon polarons to the strong magnon-phonon coupling induced by Dzyaloshinskii-Moriya interaction. Intriguingly, we find that the band-inverted magnon polarons are topologically nontrivial. These results uncover exotic elementary excitations arising from the magnon-phonon coupling, and offer a new route to topological states by considering hybridizations between different types of fundamental excitations.
Shangguan, Y.*; Bao, S.*; Dong, Z.-Y.*; Xi, N.*; Gao, Y.-P.*; Ma, Z.*; Wang, W.*; Qi, Z.*; Zhang, S.*; Huang, Z.*; et al.
Nature Physics, 19(12), p.1883 - 1889, 2023/09
被引用回数：19 パーセンタイル：94.23(Physics, Multidisciplinary)The magnetization of a quantum magnet can be pinned at a fraction of its saturated value by collective effects. One example of such a plateau phase is found in spin-1/2 triangular-lattice antiferromagnets. They feature strong geometrical frustration and the plateau phase therein is often interpreted as arising from an order-by-disorder mechanism driven by quantum fluctuations. Here we observe a one-third magnetization plateau under an applied magnetic field in the spin-1 antiferromagnet NaNiBiO with a honeycomb lattice, which, with conventional magnetic interactions, would not be geometrically frustrated. Based on our elastic neutron scattering measurements, we propose the spin structure of the plateau phase to be an unusual partial spin-flop ferrimagnetic order. Our theoretical calculations indicate that bond-anisotropic Kitaev interactions are the source of frustration that produces the plateau. These results suggest that Kitaev interactions provide a different route to frustration and phases driven by quantum fluctuations in high-spin magnets.
Ratliff, H.; McGirl, N. A.*; Beach, M. R.*; Castellanos, L. A.*; Clowdsley, M. S.*; Heilbronn, L. H.*; LaTessa, C.*; Norbury, J. W.*; Rusek, A.*; Sivertz, M.*; et al.
Nuclear Instruments and Methods in Physics Research B, 542, p.87 - 94, 2023/09
被引用回数：1 パーセンタイル：28.72(Instruments & Instrumentation)Experiments at the NASA Space Radiation Laboratory were performed to develop a benchmark dataset relevant to space radiation shielding scenarios by bombarding aluminum and polyethylene targets with galactic cosmic ray-like ion beams. Unique to this experiment, a dual-target configuration was used to emulate an enclosed environment in space in which the radiation environment must be characterized. Neutrons produced by interactions in both thick targets were detected and characterized; this paper discusses the neutrons produced in the most upstream of the two thick targets, detailing the role of source ion and target configuration on neutron yield.
O近藤 洋介*; Achouri, N. L.*; Al Falou, H.*; Atar, L.*; Aumann, T.*; 馬場 秀忠*; Boretzky, K.*; Caesar, C.*; Calvet, D.*; Chae, H.*; et al.
Nature, 620(7976), p.965 - 970, 2023/08
被引用回数：24 パーセンタイル：95.07(Multidisciplinary Sciences)非常に中性子が過剰な原子核Oは、陽子、中性子ともに魔法数であることから古くからその性質に興味が持たれていたが、酸素の最後の束縛核
Oよりも中性子が4個も多いため、これまで観測されてこなかった。この論文では、理化学研究所RIBFにて
Fからの1陽子ノックアウト反応によってOを生成し、そこから放出される中性子を測定することによって初めてその観測に成功した。核構造の観点からは、Oでは二重閉殻が保たれているか興味が持たれていたが、実験で得られた分光学的因子が殻模型計算で予言されて程度の大きいことから、閉殻構造をもたない可能性が高いことがわかった。
SnSeRen, Q.*; Gupta, M. K.*; Jin, M.*; Ding, J.*; Wu, J.*; Chen, Z.*; Lin, S.*; Fabelo, O.*; Rodriguez-Velamazan, J. A.*; 古府 麻衣子; et al.
Nature Materials, 22(8), p.999 - 1006, 2023/08
被引用回数：72 パーセンタイル：99.21(Chemistry, Physical)Ultralow thermal conductivity and fast ionic diffusion endow superionic materials with excellent performance both as thermoelectric converters and as solid-state electrolytes. Yet the correlation and interdependence between these two features remain unclear owing to a limited understanding of their complex atomic dynamics. Here we investigate ionic diffusion and lattice dynamics in argyrodite AgSnSe using synchrotron X-ray and neutron scattering techniques along with machine-learned molecular dynamics. We identify a critical interplay of the vibrational dynamics of mobile Ag and a host framework that controls the overdamping of low-energy Ag-dominated phonons into a quasi-elastic response, enabling superionicity. Concomitantly, the persistence of long-wavelength transverse acoustic phonons across the superionic transition challenges a proposed 'liquid-like thermal conduction' picture. Rather, a striking thermal broadening of low-energy phonons, starting even below 50 K, reveals extreme phonon anharmonicity and weak bonding as underlying features of the potential energy surface responsible for the ultralow thermal conductivity (
0.5 Wm
K) and fast diffusion. Our results provide fundamental insights into the complex atomic dynamics in superionic materials for energy conversion and storage.
Ca cast doubt on a doubly magic 
CaChen, S.*; Browne, F.*; Doornenbal, P.*; Lee, J.*; Obertelli, A.*; 角田 佑介*; 大塚 孝治*; 茶園 亮樹*; Hagen, G.*; Holt, J. D.*; et al.
Physics Letters B, 843, p.138025_1 - 138025_7, 2023/08
被引用回数：7 パーセンタイル：83.07(Astronomy & Astrophysics)
Scからの1陽子ノックアウト反応を用いて、
Caと
Caのガンマ崩壊を観測した。Caでは1456(12)keVの線遷移が、Caでは1115(34)keVの遷移が観測された。どちらの遷移も暫定的に
と割り当てられた。有効核子間相互作用をわずかに修正した広い模型空間での殻模型計算では、
準位エネルギー、2中性子分離エネルギー、反応断面積が実験とよく一致し、N=34閉殻の上に新しい殻が形成されていることを裏付けた。その構成要素である
と
軌道はほぼ縮退しており、これはCaが二重魔法核である可能性を排除し、Ca同位体のドリップラインを
Caあるいはそれ以上にまで広げる可能性がある。
Ne at the transition into the island of inversion; Detailed structure study of NeWang, H.*; 安田 昌弘*; 近藤 洋介*; 中村 隆司*; Tostevin, J. A.*; 緒方 一介*; 大塚 孝治*; Poves, A.*; 清水 則孝*; 吉田 数貴; et al.
Physics Letters B, 843, p.138038_1 - 138038_9, 2023/08
被引用回数：4 パーセンタイル：62.61(Astronomy & Astrophysics)Neからの1中性子除去反応を用いて、Neの詳細な線分光を行った。平行運動量分布の解析に基づき、Neの準位構造とスピンパリティを決定し、初めて負のパリティ状態を同定した。測定された断面積と運動量分布から、N=20とN=28のシェルギャップの消失の証拠となる有意なintruder p-wave強度が明らかになった。束縛状態については、弱いf-waveの可能性のある強度が観測された。いくつかの有効相互作用を用いた大規模殻模型計算では、実験的に観測された大きなp-wave強度と小さなf-wave強度は再現されず、Ne同位体に沿った反転の島への遷移の完全な理論的記述への挑戦が続いていることを示している。
