Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
van der Waals magnet
-UTe
酒井 宏典; 田端 千紘; 金子 耕士; 常盤 欣文; 北澤 崇文; 神戸 振作*; 徳永 陽; 芳賀 芳範
Physical Review B, 114(8), p.L080402_1 - L080402_6, 2026/08
被引用回数:1 パーセンタイル:73.91(Materials Science, Multidisciplinary)単斜晶ZrSe
型構造を持つファンデルワールス(vdW)アクチノイド化合物
-UTe
は、
モーメントを有する狭ギャップ半導体である。
Te NMRにより、20K以下で層内に閉じ込められた強い異方的スピン揺らぎが観測され、特に
軸成分が増強すること、また反強磁性(AFM)転移温度
KでNMR信号が消失することが明らかになった。単結晶中性子回折により、磁気伝播ベクトル
と、
軸方向にAFM積層した
軸モーメントの縦型正弦波変調が見出され、その振幅は
であった。結晶場一重項-一重項誘起モーメントの枠組みにより、容易軸異方性、
における小さな比熱異常、縮小した秩序モーメント、および局在
vdW磁性体における交換相互作用に駆動された
の選択が説明される。本研究は、制約された交換相互作用の幾何学が面内非整合磁気状態を安定化することを示すものである。
SO
(OH)
Prokhnenko, O.*; 金子 耕士; 田端 千紘; 赤木 満*; Lee, C.*; 山中 隆義*; 酒井 宏典; 廣瀬 雄介; Gazizulina, A.*; 常盤 欣文; et al.
Physical Review B, 114(1), p.014414_1 - 014414_13, 2026/07
被引用回数:0 パーセンタイル:0.00(Materials Science, Multidisciplinary)We report a comprehensive study of spin-
quantum magnet brochantite, Cu
SO
(OH)
, combining high-field thermodynamic measurements, polarized neutron diffraction, inelastic neutron scattering, and nuclear magnetic resonance spectroscopy. Using bulk magnetization and specific heat measurements we construct the magnetic
-
phase diagram for magnetic fields applied along main crystallographic directions. Polarized neutron diffraction reveals a noncollinear magnetic ground state confined to the ab plane. A field-induced transition is observed for magnetic fields in the ab plane whose critical field and character evolve continuously with field direction in the ab plane. The experimental results demonstrate that the ground-state and field-induced phases cannot be explained by a simple XXZ model with a single dominant exchange interaction and that weaker interchain and anisotropic interactions have to be taken into account. Our work establishes brochantite as a low-symmetry Cu-based quantum magnet with noncollinear order and complex field-induced behavior.
Al
東中 隆二*; Iwami, Takuma*; Saito, Kosuke*; 伊藤 孝; 田端 千紘; 金子 耕士; 大原 高志; 鬼柳 亮嗣; 中尾 朗子*; 中村 惇平*; et al.
Journal of the Physical Society of Japan, 95(6), p.063702_1 - 063702_5, 2026/06
被引用回数:0 パーセンタイル:0.00(Physics, Multidisciplinary)Neutron scattering and muon spin rotation (mSR) measurements on single-crystal SmAu
Al
reveal magnetically ordered states associated with successive transitions at 2.8 K and 0.9 K. Magnetic Bragg peaks appear below TN with an incommensurate propagation vector q = (0.30, 0, 1.33). mSR detects spontaneous internal fields below 2.8 K, and the spectral shape is consistent with the incommensurate magnetic ordering. No anomalies are observed at 0.9 K, indicating that the magnetic structure remains essentially unchanged.
PtGe
松田 駿汰*; 日比野 瑠央*; 田端 千紘; 金子 耕士; 比嘉 野乃花*; 鬼丸 孝博*; 田中 裕斗*; 藤 秀樹*; 菅原 仁*; 林 純一*; et al.
Physical Review B, 113(19), p.195116_1 - 195116_8, 2026/05
被引用回数:0 パーセンタイル:0.00(Materials Science, Multidisciplinary)The spontaneous Hall effect, corresponding to a zero-field anomalous Hall effect (AHE), is induced by symmetry breaking associated with ferromagnetism. Studies in recent years, however, have revealed that antiferromagnetic (AFM) states characterized by magnetic point groups that allow ferromagnetism can also break the relevant symmetries and induce AHE without a large net magnetization. Here, we report that the AFM system Ce
PtGe
exhibits a pronounced spontaneous Hall effect. Single-crystal neutron scattering experiments demonstrate that Ce
PtGe
exhibits a collinear AFM structure with a propagation vector
= 0. The small net magnetization indicates that the observed AHE arises from symmetry breaking inherent to its AFM structure. The anomalous Hall conductivity (AHC) reaches 300 
cm
, which exceeds the intrinsic AHC of related compounds such as Ce
CuGe
and Ce
PdGe
. This large AHC, most likely attributed to the large spin-orbit coupling of the Pt atoms, provides a platform for understanding the interplay between the Berry curvatures and localized f-moments with an AFM configuration.
In
Ge
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 EuIr
In
Ge
, 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.
藤原 理賀; 萩原 雅人; 石角 元志*; Sari, D. P.*; 渡邊 功雄*; 髭本 亘; 田端 千紘; 金子 耕士
Physical Review B, 113(6), p.064409_1 - 064409_8, 2026/02
被引用回数:0 パーセンタイル:0.00(Materials Science, Multidisciplinary)We report a field-induced quantum first-order transition in the antiferromagnet KCoPO
H
O. Using highly oriented microcrystals with
, polarized neutron diffraction directly reveals coexistence of an incommensurate cycloid and a commensurate collinear state, together with a discontinuous jump of the ordering wave vector from incommensurate to commensurate. Magnetization and specific heat show a step and a collapse of the
anomaly near
~T with no measurable hysteresis, while LF-
SR detects two-component relaxation and slow fluctuations around
. The
-
phase diagram exhibits a narrow coexistence region. Symmetry of space group
constrains the DM vector to the
plane and, together with XY anisotropy, nearly degenerates the incommensurate and commensurate states, enabling a first-order switch in field. KCoPO
H
O thus serves as a platform for quantum first-order transitions in frustrated magnets.
O
Prokhnenko, O.*; Nikitin, S. E.*; 金子 耕士; 田端 千紘; 廣瀬 雄介; 常盤 欣文; 芳賀 芳範; 藤田 全基; 野尻 浩之*; Anovitz, L. M.*; et al.
Physical Review B, 112(9), p.094402_1 - 094402_7, 2025/09
被引用回数:0 パーセンタイル:0.00(Materials Science, Multidisciplinary)The spin dynamics in the natural mineral aegirine, NaFeSi
O
, a member of the pyroxene family, was studied using elastic and inelastic neutron scattering. Magnetization and specific heat measurements as well as single-crystal neutron diffraction maps confirm two successive magnetic transitions at 8.8 and 5.8~K, consistent with previous studies. The observed spin-wave excitations emerge from the incommensurate magnetic Bragg peaks corresponding to the propagation vector
, and extend up to energies of about 1.5 meV. In the low-temperature helical phase, the spin dynamics of the Fe
ions is well described by a simple linear spin-wave model. The observed excitations can be modeled using a spin Hamiltonian that includes three primary exchange interactions. Our results show that no single exchange interaction dominates the spin dynamics. The similar strengths of the intrachain and interchain couplings point to the fact that the magnetic interactions in aegirine are three-dimensional, rather than being confined along one direction. As a result, the system cannot be considered quasi-one-dimensional, as previously suggested, and calls for further investigations.
田端 千紘; 今 布咲子*; 日比野 瑠央*; 清水 悠晴*; 網塚 浩*; 金子 耕士; 本間 佳哉*; 青木 大*; 中尾 裕則*
Journal of the Physical Society of Japan, 94(8), p.083701_1 - 083701_5, 2025/07
被引用回数:6 パーセンタイル:79.12(Physics, Multidisciplinary)Resonant X-ray scattering at the uranium M4 edge revealed successive phase transitions in URhSn. An antiferro-quadrupole (AFQ) order with propagation vector q = 0 emerges between 16 K and 54 K. Below 16 K, this AFQ order coexists with a canted magnetism, leading to a ground state that breaks mirror symmetry and exhibits chirality or polarity.
Bi
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
被引用回数:20 パーセンタイル:97.55(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
Bi
, where the Ti kagome electronic structure interacts with a magnetic sublattice of Ce
= 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.
under pressureKnafo, W.*; Thebault, T.*; Raymond, S.*; Manuel, P.*; Khalyavin, D. D.*; Orlandi, F.*; Ressouche, E.*; Beauvois, K.*; Lapertot, G.*; 金子 耕士; et al.
Physical Review X, 15(2), p.021075_1 - 021075_16, 2025/05
被引用回数:11 パーセンタイル:93.08(Physics, Multidisciplinary)The discovery of multiple superconducting phases in UTe
boosted research on correlated-electron physics. This heavy-fermion paramagnet was rapidly identified as a reference compound to study the interplay between magnetism and unconventional superconductivity with multiple degrees of freedom. The proximity to a ferromagnetic quantum phase transition was initially proposed as a driving force to triplet-pairing superconductivity. However, we find here that long-range incommensurate antiferromagnetic order is established under pressure. The propagation vector k
= (0.07, 0.33, 1) of the antiferromagnetic phase is close to a wavevector where antiferromagnetic fluctuations have previously been observed at ambient pressure. These elements support that UTe
is a nearly-antiferromagnet at ambient pressure. Our work appeals for theories modelling the evolution of the magnetic interactions and electronic properties, driving a correlated paramagnetic regime at ambient pressure to a long-range antiferromagnetic order under pressure. A deeper understanding of itinerant-f-electrons magnetism in UTe
will be a key for describing its unconventional superconducting phases.
平田 芳信*; 中川 洋; 山内 宏樹; 金子 耕士; 萩原 雅人; 山口 秀幸*; 今泉 鉄平*; 西津 貴久*
International Journal of Biological Macromolecules, 306, p.141668_1 - 141668_7, 2025/03
被引用回数:8 パーセンタイル:84.18(Biochemistry & Molecular Biology)中性子準弾性散乱(QENS)を用いて、炊飯米澱粉の老化における分子ダイナミクスに及ぼす米に対する水の割合の影響を調べた。X線回折と示差走査熱量測定の結果、炊飯用米澱粉の結晶化度にはほとんど差が認められなかったが、再結晶化の程度とエンタルピーの変化は、加水量の増加とともに小さくなることがわかった。QENS測定の結果、ゲル化試料の弾性非干渉性構造因子(EISF)値は、炊飯加水量の増加とともに小さくなり、加水量の多いゲル化米澱粉のダイナミクスが空間的に拡張していることがわかった。
=
antiferromagnetic tetramer compound Yb
SiO
長谷 正司*; 金子 耕士; 田端 千紘; 山内 宏樹; 辻井 直人*; D
nni, A.*
Physical Review B, 111(9), p.094403_1 - 094403_9, 2025/03
被引用回数:1 パーセンタイル:21.19(Materials Science, Multidisciplinary)We studied magnetic properties of Yb
SiO
having pseudospins of
=
using magnetization, specific heat, and inelastic neutron scattering (INS) measurements. We observed cluster-like excitations in the INS measurements. We determined that the spin system in Yb
SiO
is the
=
AFM tetramer with two exchange interactions of
and
~meV. The spin tetramer can explain the excitation energies,
, magnetic specific heat at
~K, and the magnitude of the scattering vector (
) dependence of the intensity [
] at 0.7 and 1.2 meV. The spin tetramer, however, cannot explain well
at 1.9 meV and
of the three excitations probably due to effects of weak inter-tetramer interactions.
CuZn
P
May, A. F.*; 田端 千紘; Okamoto, Satoshi*; Ortiz, B. R.*; Christianson, A. D.*; Yan, J.*; 金子 耕士; McGuire, M. A.*
Physical Review Materials (Internet), 9(2), p.024406_1 - 024406_13, 2025/02
被引用回数:7 パーセンタイル:75.82(Materials Science, Multidisciplinary)The physical properties of single crystalline Eu
CuZn
P
were inspected via thermodynamic, transport, and neutron diffraction measurements. Eu
CuZn
P
is composed of EuCuP and EuZn
P
motifs stacked in a one-to-one ratio. The magnetic response of Eu
CuZn
P
is similar to that of EuZn
P
in its A-type antiferromagnetic (semiconducting) form.
小手川 恒*; 中村 彰良*; Huyen, V. T. N.*; 新井 祐樹*; 藤 秀樹*; 菅原 仁*; 林 純一*; 武田 圭生*; 田端 千紘; 金子 耕士; et al.
Physical Review B, 110(21), p.214417_1 - 214417_8, 2024/12
被引用回数:4 パーセンタイル:37.43(Materials Science, Multidisciplinary)In this study, we show that the orthorhombic system TaMnP exhibits a large anomalous Hall conductivity (AHC) in spite of the small net magnetization. Neutron scattering experiment and the observation of the AH effect comprehensively suggest a dominant AF structure in TaMnP is represented by
. The AHC is one of the largest among those observed in AF materials at zero fields. First-principles calculations suggest that the spin-orbit interaction originating in nonmagnetic Ta-5
electrons significantly contributes to the enhancement of Berry curvatures in the momentum space. We found that the AF domain switching is triggered by the magnetic fields along all the crystal axes. This indicates that the AF domain determining the sign of the Hall response can be controlled even through the small net magnetization symmetrically different.
-Mn荒木 新吾*; 岩本 凱成*; 秋葉 和人*; 小林 達生*; 宗像 孝司*; 金子 耕士; 長壁 豊隆
Physical Review B, 110(9), p.094420_1 - 094420_7, 2024/09
被引用回数:1 パーセンタイル:7.96(Materials Science, Multidisciplinary)
-Mn相は、自発磁化が0.02
/Mnと比較的小さいにもかかわらず、圧力誘起弱強磁性(WFM)状態で大きな異常ホール効果(AHE)を示す。このAHEの背後にある根本的な機構を理解するために、2.0GPaの圧力下で単結晶中性子回折測定を行い、WFM相の磁気構造を決定した。I、II、III-1、IV-1位置のMnは、ほぼコリニアーな磁気モーメントが[001]方向に揃ったフェリ磁性構造を持つことを見出した。一方で、III-2とIV-2位置のMnの微小な磁気モーメントは(001)面内を向いている。この磁気構造で計算したネットの磁気モーメントの大きさ(-0.020
0.005)
/Mn原子)は、実験で決定された自発磁化と非常によく一致する。
= (0, 0, 0)での磁気反射の観測は、AHEの出現の重要な条件を満たしている。
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
Mn
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
の磁気モーメントは、約5
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
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。
triangular skyrmion lattice state in the cubic chiral helimagnet EuPtSi松村 武*; 田端 千紘; 金子 耕士; 中尾 裕則*; 垣花 将司*; 辺土 正人*; 仲間 隆男*; 大貫 惇睦*
Physical Review B, 109(17), p.174437_1 - 174437_8, 2024/05
被引用回数:17 パーセンタイル:82.84(Materials Science, Multidisciplinary)We investigated the magnetic helicity of the triple-
magnetic structure of the triangular skyrmion lattice in the A-phase of EuPtSi for a magnetic field along the [111] axis by resonant X-ray diffraction using a circularly polarized beam. We show that all three Fourier components of the triple-
structure are perpendicular to the respective
vectors and have the same helicity. They are connected by the rotation operations about the [111] axis. The helicity is the same as that of the single-
helimagnetic phase at low fields, suggesting that the antisymmetric exchange interaction inherent in the chiral structure supports the formation of the triangular skyrmion lattice. We also observe that the helical plane in the helimagnetic phase is tilted to the magnetic field to form a conical structure before the first-order transition to the skyrmion lattice phase.
Pt
Ga
studied by resonant X-ray and neutron scattering田端 千紘; 今 布咲子*; 太田 玖吾*; 日比野 瑠央*; 松本 裕司*; 網塚 浩*; 中尾 裕則*; 芳賀 芳範; 金子 耕士
Physical Review B, 109(13), p.134403_1 - 134403_7, 2024/04
被引用回数:3 パーセンタイル:28.31(Materials Science, Multidisciplinary)Antiferromagnetic (AF) order of U
Pt
Ga
with the ordering temperature 
= 26 K was investigated by resonant X-ray scattering and neutron diffraction on single crystals. This compound possesses a unique crystal structure in which uranium ions form honeycomb layers and then stacks along the c-axis with slight offset, which gives rise to a stacking disorder. The AF order can be described with the propagation vector of q = (1/6, 1/6, 0) in the hexagonal notation. The ordered magnetic moments orient perpendicular to the honeycomb layers, indicating a collinear spin structure consistent with Ising-like anisotropy. The magnetic reflections are found to be broadened along c
indicating that the stacking disorder results in anisotropic correlation lengths. The semiquantitative analysis of neutron diffraction intensity, combined with group theory considerations based on the crystallographic symmetry, suggests a zig-zag type magnetic structure for the AF ground state, in which the AF coupling runs perpendicular to the stacking offset, characterized as q = (1, 0, 0). The realization of the zig-zag magnetic structure implies the presence of frustrating intralayer exchange interactions involving both ferromagnetic (FM) first-neighbor and AF second and third-neighbor interactions in this compound.
金子 耕士; 田端 千紘; 萩原 雅人; 山内 宏樹; 大場 洋次郎; 熊田 高之; 久保田 正人; 児島 佑樹*; 生田目 望; 佐々木 未来; et al.
JPS Conference Proceedings (Internet), 41, p.011015_1 - 011015_6, 2024/03
We will introduce our recent update on low temperature system for neutron diffraction experiments. This is characterized by advantages such as liquid He free and sophisticated automatic temperature control functions, which can be a new standard for low temperature and high magnetic field experiments of neutron scattering.
Pt
Al
太田 玖吾*; 松本 裕司*; 渡部 悠貴*; 金子 耕士; 田端 千紘; 芳賀 芳範
New Physics; Sae Mulli, 73(12), p.1170 - 1173, 2023/12
ハニカム格子を持つ反強磁性体U
Pt
Al
の磁気構造を決定するために中性子散乱実験を行った。U
Pt
Al
は
=9Kと
=26Kで二つの相転移を示す。
の第一相では、
=(1/3, 0, 0)の伝搬ベクトルで記述される磁気反射が観測された。

のフェーズIIでは、
=(1/3, 0, 0)と
=(1/2, 0, 0)の磁気反射が観測され、
=(1/3, 0, 0)の磁気反射強度は弱いが有限であった。温度依存強度のヒステリシスは
での相転移にまたがって観測され、
での転移が1次転移であることを示唆している。