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論文

Spin density wave and van Hove singularity in the kagome metal CeTi$$_3$$Bi$$_4$$

Park, P.*; Ortiz, B. R.*; Spargue, M.*; Sakuya, A. P.*; Chen, S. A.*; Frontzek, M. D.*; Tian, W.*; Sibille, R.*; Mazzone, D. G.*; 田端 千紘; et al.

Nature Communications (Internet), 16, p.4384_1 - 4384_9, 2025/05

https://doi.org/10.1038/s41467-025-59460-4
 被引用回数：1 パーセンタイル：0.00(Multidisciplinary Sciences)

Kagome metals with van Hove singularities (VHSs) near the Fermi level can host intriguing quantum phenomena, including chiral loop currents, electronic nematicity, and unconventional superconductivity. However, unconventional magnetic states driven by VHSs, such as spin-density waves (SDWs), have yet to be observed experimentally in kagome metals. Here, we present a comprehensive investigation of the magnetic and electronic structure of the layered kagome metal CeTi$$_3$$Bi$$_4$$, where the Ti kagome electronic structure interacts with a magnetic sublattice of Ce$$^{3+}$$ $$J_{rm eff}$$ = 1/2 moments. Our findings establish the rare-earth Kagome metals LnTi3Bi4 as a model platform where characteristic electronic structure of the kagome lattice plays a pivotal role in magnetic order.

論文

The Influence of structural dynamics in two-dimensional hybrid organic-inorganic perovskites on their photoluminescence efficiency; Neutron scattering analysis

Rajeev, H. S.*; Hu, X.*; Chen, W.-L.*; Zhang, D.*; Chen, T.*; 古府 麻衣子*; 梶本 亮一; 中村 充孝; Chen, A. Z.*; Johnson, G. C.*; et al.

Journal of the Physical Society of Japan, 94(3), p.034602_1 - 034602_14, 2025/03

https://doi.org/10.7566/JPSJ.94.034602
 被引用回数：0 パーセンタイル：0.00(Physics, Multidisciplinary)

Two-dimensional hybrid organic-inorganic perovskites (HOIPs) have emerged as promising materials for light-emitting diode applications. In this study, by using time-of-flight neutron spectroscopy we identified and quantitatively separated the lattice vibrational and molecular rotational dynamics of two perovskites, butylammonium lead iodide (BA)$$_{2}$$PbI$$_{4}$$ and phenethyl-ammonium lead iodide (PEA)$$_{2}$$PbI$$_{4}$$. By examining the corresponding temperature dependence, we found that the lattice vibrations, as evidenced by neutron spectra, are consistent with the lattice dynamics obtained from Raman scattering. We revealed that the rotational dynamics of organic molecules in these materials tend to suppress their photoluminescence quantum yield (PLQY) while the vibrational dynamics did not show predominant correlations with the same. Additionally, we observed photoluminescence emission peak splitting for both systems, which becomes prominent above certain critical temperatures where the suppression of PLQY begins. This study suggests that the rotational motions of polarized molecules may lead to a reduction in exciton binding energy or the breaking of degeneracy in exciton binding energy levels, enhancing non-radiative recombination rates, and consequently reducing photoluminescence yield. These findings offer a deeper understanding of fundamental interactions in 2D HOIPs and could guide the design of more efficient light-emitting materials for advanced technological applications.

論文

$$mu$$SR study on the noncentrosymmetric superconductor NbGe$$_2$$

Jiao, J. C.*; Chen, K. W.*; Hillier, A. D.*; 伊藤 孝; 髭本 亘; Li, Z.*; Lv, B.*; Xu, Z.-A.*; Shu, L.*

Physical Review B, 110(21), p.214516_1 - 214516_9, 2024/12

https://doi.org/10.1103/PhysRevB.110.214516
 被引用回数：0 パーセンタイル：0.00(Materials Science, Multidisciplinary)

We report on a muon spin relaxation ($$mu$$SR) study on the polycrystalline noncentrosymmetric superconductor NbGe$$_2$$ with superconducting transition temperature $$T_c$$ = 2.0-2.1 K. The zero-field $$mu$$SR experiment indicates the absence of a spontaneous magnetic field in the superconducting state, showing the preservation of time-reversal symmetry in the superconducting state. The transverse-field $$mu$$SR experiment is performed to map the phase diagram of NbGe$$_2$$, from which clear evidence of both type-I and type-II superconductivities is obtained. More importantly, we clearly delineate the region in the phase diagram where type-I and type-II superconductivities coexist.

論文

Methanotrophic ${it Methanoperedens}$ archaea host diverse and interacting extrachromosomal elements

Shi, L.-D.*; West-Roberts, J.*; Schoelmerich, M. C.*; Penev, P. I.*; Chen, L.-X.*; 天野 由記; Lei, S.*; Sachdeva, R.*; Banfield, J. F.*

Nature Microbiology (Internet), 9(9), p.2422 - 2433, 2024/09

https://doi.org/10.1038/s41564-024-01740-8
 被引用回数：1 パーセンタイル：39.49(Microbiology)

Methane emissions that contribute to climate change can be mitigated by anaerobic methane-oxidizing archaea such as ${it Methanoperedens}$. Some ${it Methanoperedens}$ have huge extrachromosomal genetic elements (ECEs) called Borgs that may modulate their activity, yet the broader diversity of ${it Methanoperedens}$ ECEs is little studied. Here, we report small enigmatic linear ECEs, circular viruses and unclassified ECEs, that we predict replicate within ${it Methanoperedens}$. The linear ECEs have features such as inverted terminal repeats, pervasive tandem repeats, and coding patterns that are strongly reminiscent of Borgs, but they are only 52 kb to 145 kb in length. They share proteins with Borgs and ${it Methanoperedens}$. Thus, we refer to them as mini-Borgs. Mini-Borgs are genetically diverse and we assign them to at least five family-level groups. We also identify eight novel families of ${it Methanoperedens}$ viruses, some of which encode multiheme cytochromes, and unclassified circular ECEs that encode TnpB genes. A population-heterogeneous CRISPR array is encoded in close proximity to TnpB and has spacers that target other ${it Methanoperedens}$ ECEs including previously reported plasmids. The diverse groups of ECEs exchange genetic information with each other and with ${it Methanoperedens}$, likely impacting the activity and evolution of these environmentally important archaea.

論文

Magnetic excitation in the hyperkagome antiferromagnet Mn$$_{3}$$RhSi

社本 真一; 山内 宏樹; 飯田 一樹*; 池内 和彦*; 金子 耕士; Chen, Y.-S.*; 矢野 真一郎*; Hsu, P.-T.*; Lee, M. K.*; Hall, A. E.*; et al.

Physical Review Research (Internet), 6(3), p.033303_1 - 033303_7, 2024/09

https://doi.org/10.1103/PhysRevResearch.6.033303

Mn$$_{3}$$RhSiの磁気励起は少なくとも0.3から140meVに広がる。200Kでの非弾性散乱強度を積分することで、Mnサイト当たり約5$$mu_{B}$$の磁気モーメントは、約5$$mu_{B}$$であることがわかった。一方で、長距離磁気秩序の磁気モーメントは4Kでわずか2.61$$mu_{B}$$であり、多くの部分が低温まで揺らいでいることがわかった。

論文

Gradient residual strain determination of surface impacted railway S38C axles by neutron Bragg-edge transmission imaging

Hu, F. F.*; Qin, T. Y.*; Ao, N.*; Su, Y. H.; Zhou, L.*; 徐 平光; Parker, J. D.*; 篠原 武尚; Chen, J.*; Wu, S. C.*

Engineering Fracture Mechanics, 306, p.110267_1 - 110267_18, 2024/08

https://doi.org/10.1016/j.engfracmech.2024.110267
 被引用回数：2 パーセンタイル：55.14(Mechanics)

Non-destructive and quantitative mapping of gradient residual strain distribution in surface-hardened railway S38C axles could provide a positive reference for determining service lifetime and maintenance strategy. To tackle this concern, time-of-flight neutron Bragg-edge transmission imaging was employed by real axle samples with and without impacted crater. A novel and simple procedure to formulate the residual strain field was also developed in this work, with the transmission batch code in Appendix A. By mapping the global two- dimensional residual strains, it can be verified that the residual strains into the axle are uniformly distributed in the hoop direction. Subsequently, it was revealed that the axial and hoop residual strains, respectively in the cylinder and the long strip samples prepared from a real S38C hollow axle, indicated a gradient evolution distribution with a depth of $$sim$$ 8 mm, covering a range of -5500 $$sim$$ 1000 $$mu$$$$varepsilon$$ for axial strains and -6500 $$sim$$ 1000 $$mu$$$$varepsilon$$ for hoop strains. More importantly, the maximum compressive lattice strain of the cylinder sample was increased by 15.61%, and 22.35% at the impacting speeds of 100, and 125 m/s, respectively; and that of the long strip sample increased by 29.17%, and 43.70%, respectively. It can thus be concluded that lattice strains have redistributed around the impact crater, demonstrating the local alteration of the residual strain field. These new findings suggest the localized variation in residual strains should be taken into account while evaluating the service damage evolution of railway axles, especially those affected by high-speed impacts during operation.

論文

Giant barocaloric effects in sodium hexafluorophosphate and hexafluoroarsenate

Zhang, Z.*; 服部 高典; Song, R.*; Yu, D.*; Mole, R.*; Chen, J.*; He, L.*; Zhang, Z.*; Li, B.*

Journal of Applied Physics, 136(3), p.035105_1 - 035105_8, 2024/07

https://doi.org/10.1063/5.0211085
 被引用回数：2 パーセンタイル：35.22(Physics, Applied)

バロカロリック材料を用いた固体冷凍は、環境に優しく高効率であるため、過去10年間にわたり世界的に注目されてきた。ここでは、室温付近で立方晶から菱面体晶への相転移を起こすヘキサフルオロ燐酸ナトリウム(NaPF$$_6$$)とヘキサフルオロ砒酸ナトリウム(NaAsF$$_6$$)における巨大バロカロリック効果を報告する。われわれは中性子粉末回折により、NaPF$$_6$$の低温相の構造が空間群R$=3$の菱面体構造であることを明らかにした。NaPF$$_6$$とNaAsF$$_6$$には3つのラマン振動モード(F$$_{2g}$$, E$$_g$$, A$$_{1g}$$)が存在する。相転移温度はNaPF$$_6$$及びNaAsF$$_6$$においてそれぞれdT$$_t$$/dP=250K/GPa及び310K/GPaの割合で圧力とともに変化する。NaPF$$_6$$とNaAsF$$_6$$の圧力誘起エントロピー変化は、それぞれ約45.2Jkg$$^{-1}$$K$$^{-1}$$と35.6Jkg$$^{-1}$$K$$^{-1}$$と決定された。飽和駆動圧力は約40MPaであった。高圧下の中性子粉末回折から、バロカロリック効果は立方晶から菱面体晶への圧力誘起相転移に関係していることが示唆された。

論文

Interaction of solute manganese and nickel atoms with dislocation loops in iron-based alloys irradiated with 2.8 MeV Fe ions at 400 $$^{circ}$$C

Nguyen, B. V. C.*; 村上 健太*; Chena, L.*; Phongsakorn, P. T.*; Chen, X.*; 橋本 貴司; Hwang, T.*; 古澤 彰憲; 鈴木 達也*

Nuclear Materials and Energy (Internet), 39, p.101639_1 - 101639_9, 2024/06

https://doi.org/10.1016/j.nme.2024.101639
 被引用回数：1 パーセンタイル：0.00(Nuclear Science & Technology)

In reactor pressure vessel materials, the formation of Mn- and Ni-rich nanoclusters is a major cause of neutron irradiation embrittlement. The segregation of these solute atoms into dislocation loops has attracted attention as a mechanism to accelerate solute clustering. In this study, the behaviors of solute Mn and Ni atoms in Fe-0.6wt.%Ni, Fe-1.4wt.%Mn, and Fe-1.4wt.%Mn-0.6wt.%Ni alloys irradiated at 400 $$^{circ}$$C up to 3 dpa were analyzed using three-dimensional atom probe tomography. Solute atom clusters were observed in all materials, and their shapes were spherical, flat, and torus in FeNi, FeMn, and FeMnNi, respectively. In ternary alloy FeMnNi, Mn and Ni atoms were concentrated in the sample in the form of arcs, and the orientation of the plane containing the arcs was estimated by comparing field desorption images. The size, number density, and orientation of this structure were found to be in good agreement with those of both types of dislocation loops, namely, b = 1/2 $$<$$111$$>$$ and b = $$<$$100$$>$$, identified in a previous study using the same material. The positions of Ni and Mn enrichment did not fully overlap. Ni atoms tended to be concentrated more in the inner part of the loop than the Mn atoms. Mn atoms were enriched only in the vicinity of the dislocation loops, whereas Ni atoms showed a higher concentration inside the dislocation loops than in the bulk.

論文

Onset of collectivity for argon isotopes close to $$N=32$$

Linh, B. D.*; Corsi, A.*; Gillibert, A.*; Obertelli, A.*; Doornenbal, P.*; Barbieri, C.*; Duguet, T.*; G$'o$mez-Ramos, M.*; Holt, J. D.*; Hu, B. S.*; et al.

Physical Review C, 109(3), p.034312_1 - 034312_15, 2024/03

https://doi.org/10.1103/PhysRevC.109.034312
 被引用回数：2 パーセンタイル：74.11(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$$^{50}$$Arビームからの1中性子ノックアウト反応実験を行い、$$^{49}$$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$$1/2^-$$への分光学的因子が大きいことから、始状態の$$^{50}$$Arの基底状態において中性子が$$p_{1/2}$$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$$^{52}$$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。

論文

System of radiological protection; Towards a consistent framework on earth and in space

R$"u$hm, W.*; 伴 信彦*; Chen, J.*; Li, C.*; Dobynde, M.*; Durante, M.*; El-Jaby, S.*; 込山 立人*; 小笹 晃太郎*; 佐藤 達彦; et al.

Journal of Medical Physics - Zeitschrift f$"u$r medizinische Physik -, 34(1), p.4 - 13, 2024/02

https://doi.org/10.1016/j.zemedi.2024.01.004
 被引用回数：0 パーセンタイル：0.00(Radiology, Nuclear Medicine & Medical Imaging)

国際放射線防護委員会(ICRP)は、過去90年間に渡って世界各国や国際的な放射線防護の枠組み作りに貢献してきた。2019年、ICRPは宇宙飛行士の放射線防護に関わる様々な問題に対応したタスクグループ(TG115)を立ち上げ、地上の放射線防護体系と宇宙の放射線防護体系との共通の枠組み作りに取り組んでいる。本論文では、現時点でICRPが定めている宇宙放射線防護体系についてとりまとめて報告する。

論文

Comparison of dose and risk estimates between ISS Partner Agencies for a 30-day Lunar Mission

Shavers, M. R.*; Semones, E. J.*; Shurshakov, V.*; Dobynde, M.*; 佐藤 達彦; 込山 立人*; Tomi, L.*; Chen, J.*; El-Jaby, S.*; Straube, U.*; et al.

Journal of Medical Physics - Zeitschrift f$"u$r medizinische Physik -, 34(1), p.31 - 43, 2024/02

https://doi.org/10.1016/j.zemedi.2023.10.005
 被引用回数：2 パーセンタイル：59.20(Radiology, Nuclear Medicine & Medical Imaging)

本論文では、国際宇宙ステーションに協力している宇宙機関が、それぞれの評価方法で推定した宇宙線被ばく線量及びそのリスクを相互比較した結果を報告する。比較するミッションには、30日間の磁気圏外ミッションを選択し、宇宙線源として銀河宇宙線と太陽高エネルギー粒子の両方を考慮した。本比較結果より、各機関の線量・リスク評価方法に関する一貫性を確認することができた。本成果は、国際放射線防護委員会(ICRP)のタスクグループ115のレポートとして将来、まとめられる予定である。

論文

Quantum critical behavior of the hyperkagome magnet Mn$$_3$$CoSi

山内 宏樹; Sari, D. P.*; 安井 幸夫*; 坂倉 輝俊*; 木村 宏之*; 中尾 朗子*; 大原 高志; 本田 孝志*; 樹神 克明; 井川 直樹; et al.

Physical Review Research (Internet), 6(1), p.013144_1 - 013144_9, 2024/02

https://doi.org/10.1103/PhysRevResearch.6.013144

$$beta$$-Mn-type family alloys Mn$$_3$$$$TX$$ have three-dimensional antiferromagnetic (AFM) corner-shared triangular network. The antiferromagnet Mn$$_3$$RhSi shows magnetic short-range order (SRO) over a wide temperature range of approximately 500 K above the N$'{e}$el temperature $$T_{rm N}$$ = 190 K. Mn$$_3$$CoSi has the smallest lattice parameter and the lowest $$T_{rm N}$$ in the family compounds. The quantum critical point (QCP) from AFM to the quantum paramagnetic state is expected near a cubic lattice parameter of 6.15 $AA. Although $T_N$$ of Mn$$_3$$CoSi is only 140 K, quantum critical behavior is observed in Mn$$_3$$CoSi as the enhancement of the electronic specific heat coefficient $$gamma$$. We study how the magnetic SRO appears in Mn$$_3$$CoSi by using neutron scattering, $$mu$$SR, and physical property measurements. The experimental results show that the neutron scattering intensity of the magnetic SRO does not change much regardless of the suppressed magnetic moment in the long-range magnetic ordered state compared to those of Mn$$_3$$RhSi. The initial asymmetry drop ratio of $$mu$$SR above $$T_{rm N}$$ becomes small, and the magnetic SRO temperature $$T_{SRO}$$ is suppressed to 240 K. The results suggest that the Mn$$_3$$CoSi is close to the QCP in the Mn$$_3$$$$TX$$ system.

論文

Strongly coupled spin waves and surface acoustic waves at room temperature

Hwang, Y.*; Puebla, J.*; 近藤 浩太*; Gonzalez-Ballestero, C.*; 一色 弘成*; S$'a$nchez Mu$~n$oz, C.*; Liao, L.*; Chen, F.*; Luo, W.*; 前川 禎通*; et al.

Physical Review Letters, 132(5), p.056704_1 - 056704_7, 2024/01

https://doi.org/10.1103/PhysRevLett.132.056704
 被引用回数：17 パーセンタイル：97.80(Physics, Multidisciplinary)

Here, we report the observation of strong coupling between magnons and surface acoustic wave (SAW) phonons in a thin CoFeB film constructed in an on-chip SAW resonator by analyzing SAW phonon dispersion anticrossings. We employ a nanostructured SAW resonator design that, in contrast to conventional SAW resonators, allows us to enhance shear-horizontal strain. Crucially, this type of strain couples strongly to magnons. Our device design provides the tunability of the film thickness with a fixed phonon wavelength, which is a departure from the conventional approach in strong magnon-phonon coupling research. We detect a monotonic increase in the coupling strength by expanding the film thickness, which agrees with our theoretical model. Our work offers a significant way to advance fundamental research and the development of devices based on magnon-phonon hybrid quasiparticles.

論文

Chiral Dirac fermion in a collinear antiferromagnet

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

https://doi.org/10.1088/0256-307X/40/12/126101
 被引用回数：11 パーセンタイル：85.96(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.

論文

Validation of the $$^{10}$$Be ground-state molecular structure using $$^{10}$$Be($$p,palpha$$)$$^{6}$$He triple differential reaction cross-section measurements

Li, P. J.*; Beaumel, D.*; Lee, J.*; Assi$'e$, 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

https://doi.org/10.1103/PhysRevLett.131.212501
 被引用回数：21 パーセンタイル：94.59(Physics, Multidisciplinary)

$$^{10}$$Beのクラスター構造を($$p,palpha$$)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$"o$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、$$^{10}$$Beの比較的コンパクトな分子状態を確認した。

論文

Spiral spin cluster in the hyperkagome antiferromagnet Mn$$_{3}$$RhSi

社本 真一; 山内 宏樹; 飯田 一樹*; 池内 和彦*; Hall, A. E.*; Chen, Y.-S.*; Lee, M. K.*; Balakrishnan, G.*; Chang, L.-J.*

Communications Physics (Internet), 6, p.248_1 - 248_6, 2023/09

https://doi.org/10.1038/s42005-023-01363-1
 被引用回数：2 パーセンタイル：38.73(Physics, Multidisciplinary)

Mn$$_{3}$$RhSi単結晶の中性子散乱測定により、局所スピン相関秩序がらせん構造を持つことがわかった。磁気クラスター形成の起源の可能性を、リフシッツ不変量とグリフィス相の観点から議論し、Co$$_{7}$$Zn$$_{7}$$Mn$$_{6}$$の室温スキルミオン相とMnの非フェルミ液体挙動と比較した。

論文

Level structures of $$^{56,58}$$Ca cast doubt on a doubly magic $$^{60}$$Ca

Chen, 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

https://doi.org/10.1016/j.physletb.2023.138025
 被引用回数：9 パーセンタイル：89.00(Astronomy & Astrophysics)

$$^{57,59}$$Scからの1陽子ノックアウト反応を用いて、$$^{56}$$Caと$$^{58}$$Caのガンマ崩壊を観測した。$$^{56}$$Caでは1456(12)keVの$$gamma$$線遷移が、$$^{58}$$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$$2^{+}_{1} rightarrow 0^{+}_{gs}$$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、$$2^{+}_{1}$$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$$0_{f5/2}$$と$$0_{g9/2}$$軌道はほぼ縮退しており、これは$$^{60}$$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$$^{70}$$Caあるいはそれ以上にまで広げる可能性がある。

論文

A Colossal barocaloric effect induced by the creation of a high-pressure phase

Jiang, X.*; 服部 高典; Xu, X.*; Li, M.*; Yu, C.*; Yu, D.*; Mole, R.*; 矢野 真一郎*; Chen, J.*; He, L.*; et al.

Materials Horizons, 10(3), p.977 - 982, 2023/03

https://doi.org/10.1039/d2mh00905f
 被引用回数：26 パーセンタイル：93.14(Chemistry, Multidisciplinary)

現在の蒸気圧縮式冷凍機に代わる環境に優しい冷凍機として、バロカロリック効果に基づく固体冷凍機が世界的に注目されている。一般に、バロカロリック効果が発現する相はいずれも常圧でも存在する。ここでは、それらの物質と違って、KPF$$_{6}$$が高圧の菱面体晶相を生成することにより、巨大なバロカロリック効果を示すことを実証した。相図は、圧力依存の熱量測定、ラマン散乱測定、中性子回折測定に基づいて構築されたものである。本研究は、巨大バロカロリー効果に、高圧相の生成という新たな手法をもたらすと期待される。

論文

"Southwestern" boundary of the $$N = 40$$ island of inversion; First study of low-lying bound excited states in $$^{59}$$V and $$^{61}$$V

Elekes, Z.*; Juh$'a$sz, M. M.*; Sohler, D.*; Sieja, K.*; 吉田 数貴; 緒方 一介*; Doornenbal, P.*; Obertelli, A.*; Achouri, N. L.*; 馬場 秀忠*; et al.

Physical Review C, 106(6), p.064321_1 - 064321_10, 2022/12

https://doi.org/10.1103/PhysRevC.106.064321
 被引用回数：3 パーセンタイル：43.00(Physics, Nuclear)

$$^{59}$$Vと$$^{61}$$Vの低励起準位構造を初めて探索した。$$^{61}$$Vについては中性子ノックアウト反応と陽子非弾性散乱が、$$^{59}$$Vについては中性子ノックアウト反応データが得られた。$$^{59}$$Vについては4つ、$$^{61}$$Vについては5つの新たな遷移が確認された。Lenzi-Nowacki-Poves-Sieja (LNPS)相互作用に基づく殻模型計算との比較によって、それぞれの同位体について確認されたガンマ線のうち3つが、first 11/2$$^{-}$$状態とfirst 9/2$$^{-}$$状態からの崩壊と決定された。$$^{61}$$Vについては、($$p$$,$$p'$$)非弾性散乱断面積は四重極変形と十六重極変形を想定したチャネル結合法により解析されたが、十六重極変形の影響により、明確に反転の島に属するとは決定できなかった。

論文

Extended $$p_{3/2}$$ neutron orbital and the $$N = 32$$ shell closure in $$^{52}$$Ca

Enciu, M.*; Liu, H. N.*; Obertelli, A.*; Doornenbal, P.*; Nowacki, F.*; 緒方 一介*; Poves, A.*; 吉田 数貴; Achouri, N. L.*; 馬場 秀忠*; et al.

Physical Review Letters, 129(26), p.262501_1 - 262501_7, 2022/12

https://doi.org/10.1103/PhysRevLett.129.262501
 被引用回数：18 パーセンタイル：86.28(Physics, Multidisciplinary)

$$sim$$230MeV/nucleonでの$$^{52}$$Caからの中性子ノックアウト反応が$$gamma$$線分光と行われ、$$1f_{7/2}$$と$$2p_{3/2}$$軌道からの中性子ノックアウト反応の運動量分布が測定された。断面積は$$N=32$$の閉殻と整合し、Ca同位体での$$N=28$$と$$N=34$$閉殻と同程度に強い閉殻であることが確認された。運動量分布の分析から$$1_{f7/2}$$と$$2p_{3/2}$$軌道の平均二乗根半径の差は0.61(23)fmと決定され、これはmodified-shell-modelによる予言の0.7fmと整合した。これは、中性子過剰なCa同位体での$$2p_{3/2}$$軌道半径が大きいことが、中性子数にしたがって線形的に荷電半径が増える意外な現象の原因であることを示唆している。

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