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山本 将隆*; 日高 宏之*; 柳澤 達也*; 田端 千紘; 中尾 裕則*; 下村 晋*; 小野寺 秀也*; 網塚 浩*
Journal of the Physical Society of Japan, 95, p.053703_1 - 053703_4, 2026/05
被引用回数：0We report on the negative magnetization (NM) phenomenon characterized by a spontaneous magnetization antiparallel to an applied magnetic field in an antiferromagnetic (AFM) carbide TbNiC. The NM phenomenon in this compound is observed in the AFM state with a field cooling process at low magnetic fields below 500 Oe. The monotonic decrease in magnetization below the Neel temperature of 25 K observed in temperature dependence measurement of magnetization for TbNiC cannot be explained by Neel's classical theory of ferrimagnetism. We propose a novel ferrimagnetic model in which the NM originates from phase coupling between charge density wave and AFM orders.
石 禎浩*; 上杉 智教*; 森 義治*; 西尾 勝久
Physical Review Accelerators and Beams (Internet), 29(5), p.050101_1 - 050101_14, 2026/05
被引用回数：0In heavy-ion accelerators used for radioactive isotope production, the accelerated beam is typically directed onto a target and then discarded in a beam dump. To make more efficient use of the beam, recycling of the beam passed through the target is proposed in the framework of the so-called energy recovery internal target (ERIT). In the ERIT system, the target is irradiated by a circulating beam, while the energy lost in the target is recovered using rf cavities. So far, such a system has been realized only for proton beams. Here, an ERIT system for heavy-ion beams is demonstrated for the first time. A major challenge is the circulation of ions with multiple atomic charge states. After passing through the target, ions rapidly reach an equilibrated charge-state distribution, independent of the initial charge state. This stochastic charge-state conversion (SCSC) leads to rapid beam-emittance growth. To mitigate this effect, we develop a method to match the closed orbits and betatron functions of different charge states at the target location, based on a scaling fixed-field alternating-gradient (FFA) lattice. We present the design of such an FFA ring and show, through 6D beam-tracking simulations, that the transverse emittance growth induced by SCSC can be significantly reduced over a practical number of turns, whereas longitudinal emittance growth remains significant and is discussed separately.
magnetic order with spatially alternating spin scalar chirality in overdoped Co
TaSCho, W.*; Park, P.*; Kim, C.*; An, Y.*; 飯田 一樹*; 梶本 亮一; Matin, S.*; Sibille, R.*; Crooker, S. A.*; Park, J.-G.*
Physical Review B, 113(17), p.174410_1 - 174410_14, 2026/05
被引用回数：0Co
TaS (
) exhibits a spontaneous Hall effect from spin texture in antiferromagnets, with a tetrahedral triple-Q () order and uniform spin scalar chirality. Upon Co overdoping (
), it undergoes a shift in magnetic ordering vectors from 
to 
. Interestingly, the spontaneous Hall effect disappeared in the overdoped regime, which was originally attributed to the loss of order. However, a question remains whether a new type of order can exist with alternating chirality in the overdoped regime. To address this, we investigated CoTaS using inelastic neutron scattering (INS), neutron diffraction, and optical dichroism, and found that INS data and spin-wave simulations support a order with alternating chirality. Moreover, neutron diffraction data show field-independent Bragg peaks, while linear dichroism detects no in-plane anisotropy, consistent with threefold rotation symmetry. Our data support the scenario of an alternating-chirality order in CoTaS, cancelling the spontaneous Hall effect. This study highlights a combined neutron-optical approach to identify complex spin textures.
-iron at high pressures determined using 
neutron diffraction青木 勝敏*; 高野 将大*; 福山 鴻*; 鍵 裕之*; 町田 晃彦*; 齋藤 寛之*; 服部 高典; 佐野 亜沙美; 舟越 賢一*
Physical Review B, 113(18), p.184440_1 - 184440_6, 2026/05
被引用回数：1体心立方(bcc)-鉄の磁気モーメントの温度依存性をその場中性子粉末回折法を用いて、約2GPaおよび6GPaの圧力下で300
950Kの範囲において調べた。磁気散乱の相対寄与を高めるため、中性子散乱長が天然Feの約半分である
Fe同位体が用いられた。キュリー温度(
)は、2.1GPa, 6.0GPa, 6.7GPaでそれぞれ946(30)K、838(50)K、740(40)Kと決定され、(K) = 1043 - 49(7)
+ 1.3(1.2)
で表される磁気相境界が決定された。6.7GPaで加熱すると、磁気転移に続いて
構造転移が観測された。この結果は、磁気相境界が相境界の低温側に位置することを示している。したがって、転移は、常磁性bcc鉄から常磁性fcc鉄への構造変化に対応する。
As studied by X-ray magnetic circular dichroismWan, Y.*; 芝田 悟朗; 竹田 幸治*; 岡根 哲夫; 斎藤 祐児; 山上 浩志; 藤森 淳*; 他10名*
Physical Review Materials (Internet), 10(5), p.054402_1 - 054402_8, 2026/05
被引用回数：0In order to unveil the nature of the ferromagnetism in (Ba,K)(Zn,Mn)As, its magnetization process has been studied by X-ray magnetic circular dichroism (XMCD) at the Mn 
edge in a wide range of temperature and magnetic field. The average magnetization of the Mn atoms as a function of magnetic field (
-
curves) at various temperatures could be successfully explained by a mixture of paramagnetic (PM), superparamagnetic (SPM), and ferromagnetic (FM) components as previously reported for GaMnAs, revealing the complex nature of the ferromagnetism in (Ba,K)(Zn,Mn)As. The average magnetization of the SPM clusters of different sizes and the FM regions were found to be small compared to those in GaMnAs, which we attribute to the antiferromagnetic interaction between nearest-neighbor Mn atoms in (Ba,K)(Zn,Mn)As on the basis of recent theoretical predictions.
佐藤 優樹; 角藤 壮*; 田中 孝幸*; 嶋野 寛之*
European Physical Journal; Special Topics, 235(4), p.949 - 958, 2026/04
被引用回数：1 パーセンタイル：0.00(Physics, Multidisciplinary)In decommissioning the Fukushima Daiichi Nuclear Power Station, understanding the distribution of radioactive substances is crucial to developing detailed decontamination plans and minimizing worker exposure. In this study, an autonomous mobile radiation source detection system based on a mecanum wheel robot equipped with a Compton camera was constructed. The Compton camera visualizes the radiation source, and software embedded in the robot system reads the results to recognize the radiation source and move the robot toward it. If the robot's depth camera detects an obstacle while moving, it changes direction, visualizes the radiation source again using the Compton camera, and repeats moving the robot toward the radiation source. Furthermore, two demonstration tests were conducted in the laboratory using a 
Cs radiation source to confirm that the robot can reach it where there are obstacles or a narrow region. We have also summarized issues that must be identified to apply this system to actual decommissioning sites.
InGe studied by single crystal neutron diffraction田端 千紘; 金子 耕士; 中尾 朗子*; 大原 高志; 松田 達磨*; 大貫 惇睦*
Journal of the Physical Society of Japan, 95(5), p.053702_1 - 053702_4, 2026/04
被引用回数：0 パーセンタイル：0.00(Physics, Multidisciplinary)The magnetic order of EuIrInGe, which crystallizes in a Dresselhaus-type noncentrosymmetric tetragonal structure, was investigated using two complementary single-crystal neutron diffraction approaches. Time-of-flight single-crystal diffraction reveals antiferromagnetic Bragg reflections with propagation vector q = (0, 0, 0) below the Neel temperature TN = 2.5 K, indicating a breaking of body-centered translational symmetry. Polarized neutron diffraction on a triple-axis spectrometer demonstrates that the ordered Eu2+ 4f moments lie within the basal plane and form a collinear antiferromagnetic structure with antiparallel alignment between corner and body-center sites. Despite the Dresselhaus-type spin splitting in the conduction bands, the magnetic order remains simple, implying weak coupling between localized moments and itinerant electrons.
Sb
with an ordered honeycomb network今津 毅士; 古谷 直也*; 足立 匡*; 工藤 一貴*; 今井 剛樹*; 御領 潤*
Journal of the Physical Society of Japan, 95(4), p.044704_1 - 044704_7, 2026/04
被引用回数：0 パーセンタイル：0.00(Physics, Multidisciplinary)空間反転対称性を破る結晶構造をもつ蜂の巣格子超伝導体BaPtAsSbは超伝導転移温度のx依存性が非単調な振る舞いを示す。更にミューオンスピン緩和実験によりSbエンド(
=1)において自発磁場が観測され、時間反転対称性を破る超伝導状態が実現している可能性がある。BaPtAs(=0), BaPtSb(=1)の第一原理計算を行い、バンド構造を再現する有効強束縛模型を用いてギャップ方程式と凝縮エネルギーの解析を行い、安定となる超伝導対称性を議論した。その結果、BaPtAs(=0)では時間反転対称性のある従来型のs波超伝導とf波超伝導が安定化し、BaPtSb(=1)では時間反転対称性を破るカイラルd波状態が広く安定化することがわかった。この結果はミューオンスピン緩和実験とも整合する。また本論文で得られた知見は六方晶におけるカイラル超伝導相の探索に重要な指針を与える。
CaOsO
assessed by X-ray magnetic dichroism measurements芝田 悟朗; 藤森 淳; 他10名*
Physical Review B, 113(16), p.165151_1 - 165151_7, 2026/04
被引用回数：0We studied the cubic double perovskite BaCaOsO
containing the Os
(
) ions, which exhibits a phase transition to a `hidden order' below 
K, by X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD) at the Os edge. The cubic ligand-field splitting between the 
and 
levels of Os 
was deduced by XAS to be 
eV. The temperature dependence of the XMCD spectra was consistent with a 
meV residual cubic splitting of the lowest 
multiplet state into the non-Kramers 
doublet ground state and the 
triplet excited state. Ligand-field (LF) multiplet calculation under fictitious strong magnetic fields indicated that the exchange interaction between nearest-neighbor octupoles should be as strong as 
meV if a ferro-octupole order is stabilized in the `hidden-ordered' state, consistent with the exchange interaction of 
meV previously predicted theoretically using model and density functional theory calculations.
徳永 陽; 鈴木 通人*; Kr
mer, S.*; 酒井 宏典; 神戸 振作; 播磨 尚朝*; 青木 大*; Horvati
, M.*; Sheikin, I.*
Physical Review B, 113(14), p.L140406_1 - L140406_7, 2026/04
被引用回数：0We report low-temperature 
In nuclear magnetic resonance (NMR) study of the prototypical heavy-fermion compound CeIrIn in high magnetic fields applied close to the crystallographic 
axis. For this orientation, a field-induced transition was previously reported to take place at about 28~T. Although we do not observe any change of the NMR spectrum above the transition, the intensity of the NMR lines drastically decreases as a consequence of a considerable shortening of the 
relaxation time. In addition, 
shows a pronounced maximum at the transition. Taking into account previous high-field de Haas-van Alphen results in conjunction with band-structure calculations, our NMR results are most naturally explained by the field-induced transition into an antiferromagnetic state with the propagation vector 
and magnetic moments aligned antiferromagnetically along the axis.
森 道康; 小椎八重 航*; 前川 禎通*
Physical Review B, 113(13), p.134505_1 - 134505_8, 2026/04
被引用回数：0 パーセンタイル：0.00(Materials Science, Multidisciplinary)Josephson diode effect between two singlet superconductors separated by the Rashba system is studied theoretically. The coupling energy of two superconductors is analytically calculated using a tunneling Hamiltonian with a one-dimensional model. In a magnetic field perpendicular to an applied current, we obtain a coupling energy proportional to the applied current and magnetic field. This makes the critical current asymmetric with respect to the current or the magnetic field, i.e., Josephson diode effect. More importantly, depending on a distance between the superconducting electrodes 
, the Josephson diode effect changes its magnitude and sign. The magnitude is inversely proportional to a band split caused by the spin-orbit interaction. Since is experimentally controllable, the Josephson diode effect can be optimized by tuning of .
Prestwood, D.*; 吉川 貴史; 齊藤 英治; 他15名*
Physical Review B, 113(13), p.134410_1 - 134410_12, 2026/04
被引用回数：1 パーセンタイル：0.00(Materials Science, Multidisciplinary)We study a thin-film yttrium iron garnet sample that exhibits magnetic stripe domains due to a small perpendicular magnetic anisotropy. Using wide-field magneto-optic Kerr effect measurements we reveal the domain pattern evolution as a function of applied field and discuss the role of cubic anisotropy in the domain formation. Rich magnon spectra are observed in the stripe domain states, with a range of excitation conditions providing distinct spectra. The measurements are interpreted using micromagnetic simulations to provide the spatial profiles of each resonance mode. We further simulate domain patterns and resonance spectra accounting for the cubic anisotropy, with good correlation to experiment. This study highlights how noncollinear magnetic domain structures can host complex resonant behavior in a low-damping magnetic material, with potential use in future magnonic applications.
Er静間 俊行*; Omer, M.; 羽島 良一*; 小泉 光生; 高橋 時音; 角田 佑介*; 大塚 孝治*
Physical Review C, 113(4), p.044325_1 - 044325_9, 2026/04
被引用回数：0Low-energy dipole excitations in Er were investigated via nuclear resonance fluorescence using a quasi-monoenergetic, linearly polarized photon beam produced at the High Intensity 
-ray Source (HIS) facility at Duke University. The parity of the excited states was determined from the azimuthal asymmetry in the intensities of resonantly scattered rays with respect to the polarization plane of the incident beam. Electric and magnetic dipole strengths were extracted for excitation energies between 2.2 and 3.5 MeV. The results are interpreted in terms of the nuclear scissors mode by comparing with large-scale shell-model calculations based on the Qasiparticle Vacua Shell Model. In addition, the characteristics of the E1 excitations are examined in comparison with those of neighboring rare-earth nuclei to explore their relations to collective octupole--vibrational two-phonon excitations. This work is a contribution of the Japan Atomic Energy Agency (JAEA) to the International Atomic Energy Agency (IAEA) under the agreement of the coordinated research program (CRP), J02015 (Facilitation of Safe and Secure Trade Using Nuclear Detection Technology - Detection of RN and Other Contraband). This work was a part of the study of NRF phenomenon aiming at nuclear security and safeguards applications, being supported by the subsidiary for "promotion of strengthening nuclear security or the like" of the Ministry of Education, Culture, Sports, Science, and Technology (MEXT), Japan.
Zn
北澤 崇文; 志村 恭通*; 鬼丸 孝博*; 土田 駿*; 久保 勝規; 芳賀 芳範; 酒井 宏典; 常盤 欣文; 神戸 振作; 徳永 陽
Physical Review Research (Internet), 8(2), p.023009_1 - 023009_14, 2026/04
We investigated electron-nuclear spin entanglement in the paramagnetic ground state of the Ho-based cubic compound HoCoZn. From analyses of magnetization and specific heat data, we determined the cubic crystalline electric field (CEF) parameters, the magnetic exchange constant, and the hyperfine coupling constant between the 4
magnetic moment and the 
Ho nuclear spin. Our results show that the 
CEF ground state is split by the hyperfine coupling, with an energy width of 1.3~K at 0~T, and that the true paramagnetic ground state is a quasi-sextet arising primarily from entanglement between the -electron effective spin 
and the Ho nuclear spin 
. We further demonstrate that, depending on the CEF parameters, the paramagnetic ground state can switch to an electron-nuclear coupled dectet. These findings underscore the importance of accurately identifying the electron-nuclear level scheme for understanding the low-temperature properties of rare-earth compounds containing spin-active nuclei.
小栗 香里; 荒井 陽一; 渡部 創; 瀬古 典明*; 保科 宏行*
ソルト・サイエンス研究財団2024年度助成研究報告集(I 理工学編), p.269 - 278, 2026/03
医療用
Acの安定した国内生産を目指し、原料となる
Raを海水から効率良く、採取する技術を開発するため、様々な吸着材を合成しRaのアナログ元素であるBaを代替元素として評価した。その結果、1段階目にリン酸型(P)グラフト重合吸着材を用い、次いで吸着したBaを含む数種の元素を溶出させた酸溶液を、TEHDGA/SiO-P充填カラムに通液することでBaのみを分離できることを見いだした。これにより、海水中のRaを資源利用できる見込みが得られた。
Budai, N.*; 一色 弘成; 大谷 義近
Physical Review Applied (Internet), 25(3), p.L031002_1 - L031002_7, 2026/03
被引用回数：0 パーセンタイル：0.00(Physics, Applied)We present a magnetic imaging technique to investigate materials with perpendicular magnetic anisotropy, using a conventional atomic force microscope (AFM). In this method, the Si tip acts as a thermal anchor, generating localized in-plane temperature gradients in a heated nanowire. The resulting anomalous Nernst effect (ANE) is measured at both ends of the wire. For uniform out-of-plane magnetization, the anomalous Nernst signal reverses the sign as the tip scans from edge to edge, reflecting the direction of the local temperature gradient. By simulating this gradient, the coefficient of the ANE can be quantitatively determined. Furthermore, this technique enables the visualization of magnetic multi-domain structures. This method offers a simple, quantitative, and practical approach to magnetic imaging using widely available AFM setups.
Valet, T.*; 山本 慧; Pigeau, B.*; de Loubens, G.*; Klein, O.*
Physical Review B, 113(10), p.L100410_1 - L100410_6, 2026/03
被引用回数：0 パーセンタイル：0.00(Materials Science, Multidisciplinary)In the context of a growing interdisciplinary interest in the angular momentum of wave fields, the spin-wave case has yet to be fully explored, with the extensively studied notion of spin transport being only part of the broader picture. Here we report experimental evidence for non-zeromagnon orbital angular momentum inside magnetic disk, by resolving the frequency splitting between magnon modes with counter-rotating wavefronts and thereby avoiding formation of azimuthal standing waves. This requires an unambiguous formulation of spin and orbital angular momenta for spin waves, which we provide in full generality taking advantage of a systematic application of quantum field theory techniques as detailed in an associated article. The results unequivocally establish magnetic dipole-dipole interactions as a magnetic-field controllable spin-orbit interaction for magnons. Our findings open a new research direction, leveraging the spectroscopic readability of angular momentum for azimuthal spin waves and other related systems.
松村 拓輝*; 徳永 陽; 酒井 宏典; 神戸 振作; 木俣 基; 他14名*
Physical Review B, 113(9), p.094506_1 - 094506_12, 2026/03
被引用回数：0 パーセンタイル：0.00(Materials Science, Multidisciplinary)Spin-triplet superconductivity is an intriguing quantum coherent state with both spin and orbital degrees of freedom, which holds significant potential for future applications in quantum technology. However, how the spin of the triplet pairs responds to an external magnetic field remains poorly understood. This is mainly due to the absence of suitable spin-triplet superconductors. Here, we report results of Knight-shift and ac-susceptibility measurements on UTe. We demonstrate that the spin susceptibility, which slightly decreases compared to the normal-state value below the superconducting transition temperature 
, is rapidly restored and nearly recovers to the normal-state values around 5 T, well below the SC upper critical field 
when the magnetic field is applied along the axis.
Valet, T.*; 山本 慧; Pigeau, B.*; de Loubens, G.*; Klein, O.*
Physical Review B, 113(10), p.104437_1 - 104437_17, 2026/03
被引用回数：0 パーセンタイル：0.00(Materials Science, Multidisciplinary)In the context of an ever-expanding experimental and theoretical interest in the magnetization dynamics of mesoscopic magnetic structures, both in the classical and quantum regimes, we formulate a low-energy field theory for the linear spin waves in finite and textured ferromagnets and we perform its constrained canonical quantization. The introduction of a manifestly gauge invariant Lagrangian enables a straightforward application of the Noether's theorem. Taking advantage of this in the context of a broad class of axisymmetric ferromagnets of special conceptual and experimental relevance, a general expression of the conserved and quantized spin-wave total angular momentum is rigorously derived, while separate conservation and quantization of its orbital and spin components are established for a more restricted class of uniaxial exchange ferromagnets. Further particularizing this general framework to the case of axially saturated magnetic thin disks, we develop a semi-analytic theory of the low frequency part of the exchange-dipole azimuthal spin-wave spectrum, providing a powerful theoretical platform for the analysis and interpretation of magnetic resonance experiments on magnetic microdots as further demonstrated in a joint paper.
reactions on neutron-rich nuclei; Collectivity and resonances in low-energy cross sections斉藤 照之; 松尾 正之*
Physical Review C, 113(3), p.034607_1 - 034607_16, 2026/03
被引用回数：0 パーセンタイル：0.00(Physics, Nuclear)We formulate a microscopic theory to calculate cross section of the radiative neutron capture on neutron-rich nuclei using the continuum quasiparticle random-phase approximation (cQRPA). This formulation is designed to be applied to neutron-rich nuclei around the 
-process path, for which the compound nuclear model may not be appropriate. It takes into account effects of various excitation modes such as the soft dipole excitation, the giant resonances, and the quasiparticle resonance in addition to the surface vibrations such as quadrupole and octupole modes. We perform numerical calculations to demonstrate new features of the present theory, employing reactions 
and 
with 
transitions populating the ground state, collective 
and 
states in 
and 
. With these examples, we discuss enhanced resonance contributions in the reaction at low energy, which originate from the quasiparticle resonance and the pygmy quadrupole resonance located just above the one neutron separation energy, and from combination with the low-lying octupole vibrational state.
