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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：0

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

Incommensurate antiferromagnetism in UTe$$_2$$ under pressure

Knafo, 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

https://doi.org/10.1103/PhysRevX.15.021075

The discovery of multiple superconducting phases in UTe$$_2$$ 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$$_{rm m}$$ = (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$$_2$$ 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$$_2$$ will be a key for describing its unconventional superconducting phases.

論文

Neutron spectroscopy study on crystalline electric field excitations in NdB$$_4$$

山内 宏樹; 目時 直人; 綿貫 竜太*; Hong, T.*; Fernandez-Baca, J. A.*; 萩原 雅人; 益田 隆嗣*; 吉沢 英樹*; 伊藤 晋一*

Journal of the Physical Society of Japan, 94(5), p.054705_1 - 054705_8, 2025/04

https://doi.org/10.7566/JPSJ.94.054705

The $textit{f}$-electron states of NdB$$_4$$ were determined by observing crystalline electric field (CEF) excitations with inelastic neutron scattering experiments. Our analysis yields CEF excitation energies of 2.8, 12.4, 17.2, and 25.4 meV. The $textit{f}$-electron states are simply described by one of $$J$$-multiplets $$left|pm J_z rightrangle$$ with negligibly small mixing. The ground state is the pseudo-quartet consist of the ground doublet dominated by $$left|pm frac{5}{2} rightrangle$$ and the first excited doublet dominated by $$left|pm frac{7}{2} rightrangle$$ at 2.8 meV, which is consistent with magnetic specific heat and entropy reported in earlier study. The simple $textit{f}$-electron states in NdB$$_4$$ are the consequence of the strong uniaxial and in-plane isotropic CEF potential due to the local structure of Nd$$^{3+}$$ ions with point symmetry $$C_{2v}$$.

論文

Effect of the ratio of water to rice on the molecular dynamics of cooked rice starch during retrogradation; Implications for amorphous structure in gelatinized state

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

https://doi.org/10.1016/j.ijbiomac.2025.141668
 被引用回数：0 パーセンタイル：0.00(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。

論文

Magnetic and quadrupole coupling emerging in NdB$$_4$$ with geometrically frustrated orthogonal antiferromagnetic dimer

目時 直人; 山内 宏樹; 萩原 雅人; 綿貫 竜太*; 河村 聖子; 古府 麻衣子*; 中島 健次; 松田 雅昌*

Physical Review B, 111(10), p.104424_1 - 104424_9, 2025/03

https://doi.org/10.1103/PhysRevB.111.104424
 被引用回数：0 パーセンタイル：0.00(Materials Science, Multidisciplinary)

フラストレートしたシャストリ・サザランド格子を有するNdB$$_4$$の磁気転移を理解する目的で中性子非弾性散乱実験を行った。$$|pm frac{5}{2}rangle$$と$$|pm frac{7}{2}rangle$$による準四重項状態が磁気秩序相で4つに分裂する。スペクトルは磁気相互作用$$langle J_x rangle J_x$$、磁気$$J_x$$と四極子$$O_{zx}$$の結合、そして一軸的な結晶場により説明される。この$$f$$電子状態により、主たる秩序変数である面内磁気モーメント$$m_perp=langle J_x rangle$$と結く誘起された2次的な秩序変数$$m_c=langle J_z rangle$$を説明することができた。幾何学的フラストレーションによってハイゼンベルグ相互作用が打ち消し合う状況で、磁気と四極子の結合が本質的な役割をすることが明らかになった。

論文

Spin-singlet ground state with spin gap in $$S_{rm eff}$$ = $$frac{1}{2}$$ antiferromagnetic tetramer compound Yb$$_2$$SiO$$_5$$

長谷 正司*; 金子 耕士; 田端 千紘; 山内 宏樹; 辻井 直人*; D$"o$nni, A.*

Physical Review B, 111(9), p.094403_1 - 094403_9, 2025/03

https://doi.org/10.1103/PhysRevB.111.094403
 被引用回数：0 パーセンタイル：0.00(Materials Science, Multidisciplinary)

We studied magnetic properties of Yb$$_2$$SiO$$_5$$ having pseudospins of $$S_{rm eff}$$ = $$frac{1}{2}$$ 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$$_2$$SiO$$_5$$ is the $$S_{rm eff}$$ = $$frac{1}{2}$$ AFM tetramer with two exchange interactions of $$J_1 = 0.74$$ and $$J_2 = 0.95$$~meV. The spin tetramer can explain the excitation energies, $$chi (T)$$, magnetic specific heat at $$T < 15$$~K, and the magnitude of the scattering vector ($$Q$$) dependence of the intensity [$$I(Q)$$] at 0.7 and 1.2 meV. The spin tetramer, however, cannot explain well $$I(Q)$$ at 1.9 meV and $$I(T)$$ of the three excitations probably due to effects of weak inter-tetramer interactions.

論文

Physical properties of intergrowth compound Eu$$_{2}$$CuZn$$_{2}$$P$$_{3}$$

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

https://doi.org/10.1103/PhysRevMaterials.9.024406
 被引用回数：0 パーセンタイル：0.00(Materials Science, Multidisciplinary)

The physical properties of single crystalline Eu$$_{2}$$CuZn$$_{2}$$P$$_{3}$$ were inspected via thermodynamic, transport, and neutron diffraction measurements. Eu$$_{2}$$CuZn$$_{2}$$P$$_{3}$$ is composed of EuCuP and EuZn$$_{2}$$P$$_{2}$$ motifs stacked in a one-to-one ratio. The magnetic response of Eu$$_{2}$$CuZn$$_{2}$$P$$_{3}$$ is similar to that of EuZn$$_{2}$$P$$_{2}$$ in its A-type antiferromagnetic (semiconducting) form.

論文

Possible field-induced quantum state in a rhombic lattice antiferromagnet KCoPO$$_{4}$$$$cdot$$H$$_{2}$$O

藤原 理賀; 萩原 雅人; 幸田 章宏*; 中村 惇平*; 松尾 晶*; 金道 浩一*; 石角 元志*

Physical Review Materials (Internet), 9(1), p.014406_1 - 014406_9, 2025/01

https://doi.org/10.1103/PhysRevMaterials.9.014406
 被引用回数：1 パーセンタイル：0.00(Materials Science, Multidisciplinary)

We reported the magnetic behavior of a rhombic lattice quantum antiferromagnet KCoPO$$_{4}$$$$cdot$$H$$_{2}$$O. The rhombic lattice model is equivalent to a model of a square lattice with two different diagonal components, and competing exchange interactions potentially produce exotic quantum states. This compound is well characterized by the $$J$$$$_{rm{eff}}$$ = 1/2 state. The magnetic structure of KCoPO$$_{4}$$$$cdot$$H$$_{2}$$O is identified as an incommensurate helical structure, characterized by a magnetic modulation propagation vector $$bold{k}$$ = (0.1747(1) 0 0) with an in-plane moment rotating along the $$a$$ axis. Moreover, a magnetic field-induced phase transition is observed at approximately 1 T. The application of a magnetic field suppresses spin ordering and enhance spin fluctuations. Our experimental results suggest the presence of a quantum phase in the magnetic phase diagram of the spin-1/2 Heisenberg rhombic lattice antiferromagnet with easy-plane anisotropy.

論文

Large spontaneous Hall effect with flexible domain control in the antiferromagnetic material TaMnP

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

https://doi.org/10.1103/PhysRevB.110.214417
 被引用回数：0 パーセンタイル：0.00(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 $$B_{3g}$$. 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$$d$$ 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.

論文

Unique magnetic transition process demonstrating the effectiveness of bond percolation theory in a quantum magnet

Zheng, X.-G.*; 山内 一宏*; 萩原 雅人; 西堀 英治*; 河江 達也*; 渡邊 功雄*; 内山 智貴*; Chen, Y.*; Xu, C.-N.*

Nature Communications (Internet), 15, p.9989_1 - 9989_12, 2024/11

https://doi.org/10.1038/s41467-024-54335-6
 被引用回数：0 パーセンタイル：0.00(Multidisciplinary Sciences)

Like the crystallization of water to ice, magnetic transition occurs at a critical temperature after the slowing down of dynamically fluctuating short-range correlated spins. Here, we report a unique type of magnetic transition characterized by a linear increase in the volume fraction of unconventional static short-range-ordered spin clusters, which triggered a transition into a long-range order at a threshold fraction perfectly matching the bond percolation theory in a new quantum antiferromagnet of pseudo-trigonal Cu$$_{4}$$(OH)$$_{6}$$Cl$$_{2}$$. Static short-range order appeared in its Kagome lattice plane below Ca. 20 K from a pool of coexisting spin liquid, linearly increasing its fraction to 0.492(8), then all Kagome spins transitioned into a stable two-dimensional spin order at $$T$$_${rm N}$$$ = 5.5 K. Inspection on the magnetic interactions and quantum magnetism revealed an intrinsic link to the spin liquid material Herbertsmithite, ZnCu$$_${3}$$$(OH)$$_${6}$$$Cl$$_${2}$$. The unconventional static nature of the short-range order was inferred to be due to a pinning effect by the strongly correlated coexisting spin liquids. This work presents a unique magnetic system to demonstrate a complete bond percolation process toward the critical transition. Meanwhile, the unconventionally developed magnetic order in this chemically clean system should shed new light on spin-liquid physics.

論文

Ferrimagnetic structure in the high-pressure phase of $$alpha$$-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

https://doi.org/10.1103/PhysRevB.110.094420
 被引用回数：0 パーセンタイル：0.00(Materials Science, Multidisciplinary)

$$alpha$$-Mn相は、自発磁化が0.02$${mu}_{rm B}$$/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$${pm}$$0.005)$${mu}_{rm B}$$/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。$$q$$ = (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。

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

Ferroaxial transitions in glaserite-type Na$$_2$$Ba${it M}$(PO$$_4$$)$$_2$$ (${it M}$ = Mg, Mn, Co, and Ni)

梶田 遥一*; 永井 隆之*; 山岸 茂直*; 木村 健太*; 萩原 雅人; 木村 剛*

Chemistry of Materials, 36(15), p.7451 - 7458, 2024/08

https://doi.org/10.1021/acs.chemmater.4c01406
 被引用回数：2 パーセンタイル：56.91(Chemistry, Physical)

Ferroaxial transitions of Na$$_{2}$$Ba${it M}$(PO$$_{4}$$)$$_{2}$$ (${it M}$ = Mg, Mn, Co, and Ni) with the glaserite structure, featuring rotational distortions of PO$$_{4}$$ tetrahedra, are investigated. Neutron powder diffraction (NPD) measurements on polycrystalline samples were carried out in the temperature range from room temperature to 800 K. Structure analyses on the NPD data revealed that all of the compounds studied here have a ferroaxial structure (space group: ${it P}$ $$bar{3}$$)at room temperature and undergo a ferroaxial transition into a non-ferroaxial phase (space group: ${it P}$ $$bar {3}$$${it m}$1) upon heating. Structural parameters change continuously at the transition temperature, which suggests that the ferroaxial transition of Na$$_{2}$$Ba${it M}$(PO$$_{4}$$)$$_{2}$$ systems is of the second order. Furthermore, to examine the structural stability, ab initio phonon calculations were carried out for Na$$_{2}$$BaMg(PO$$_{4}$$)$$_{2}$$. The calculated result shows that the rotational phonon mode instability inherent in the non-ferroaxial ${it P}$ $$bar{3}$$${it m}$1 phase leads to the ${it P}$ $$bar{3}$$ phases as a ground state, which well explains the experimental result. This study revealed that Na$$_{2}$$Ba${it M}$ (PO$$_{4}$$)$$_{2}$$ systems with the glaserite structure are a class of ferroaxial compounds showing a second-order pure ferroaxial transition.

論文

Ferroelectricity induced by a combination of crystallographic chirality and axial vector

永井 隆之*; 萩原 雅人; 横井 里江*; 森分 博紀*; 木村 剛*

Journal of the American Chemical Society, 146(33), p.23348 - 23355, 2024/08

https://doi.org/10.1021/jacs.4c06283
 被引用回数：1 パーセンタイル：37.20(Chemistry, Multidisciplinary)

Ferroelectric materials compatible with magnetism and/or conductive properties provide a platform for exploring unconventional phenomena, such as the magnetoelectric effect, nonreciprocal responses, and nontrivial superconductivity. Though recent studies on multiferroics have offered several approaches, the search for magnetic and/or conducting ferroelectric materials is still a challenging issue under the traditional "d$$^{0}$$-ness" rule, refusing active d electrons. Here, we propose the emergence of ferroelectricity through a combination of crystallographic chirality and axial vector, accepting even non-d$$^{0}$$ magnetic ions. This proposal is demonstrated in quasi-one-dimensional magnetic systems SrM$$_{2}$$V$$_{2}$$O$$_{8}$$ (M = Ni, Mg, and Co). The ferroelectric phase transition is observed by measurements of neutron powder diffraction and dielectric properties in all compositions. Structural analyses and first-principles calculations indicate that these magnetic compounds are identified as proper-type ferroelectrics whose ferroelectric phase transition is achieved by spiral motions of crystallographic screw chains formed by edge-shared MO6 octahedra, considered as the combination of locally defined chirality and axial vector. Computationally predicted magnitude of spontaneous polarization of SrM$$_{2}$$V$$_{2}$$O$$_{8}$$ reaches $$sim$$10$$^{circ}$$$$mu$$C/cm$$^{2}$$, comparable to that of conventional ferroelectrics, despite the incorporation of non-d$$^{0}$$ magnetic elements. The mechanism proposed in this study offers a unique approach to the exploration of new ferroelectrics beyond the traditional paradigms.

論文

Influence of local structures on amorphous alumina exhibiting resistance random-access memory function

久保田 正人; 加藤 誠一*

Journal of Applied Physics, 136(2), p.025102_1 - 025102_5, 2024/07

https://doi.org/10.1063/5.0208486
 被引用回数：1 パーセンタイル：40.97(Physics, Applied)

We studied local structures of amorphous alumina samples and Al$$_{2}$$O$$_{3}$$ polycrystalline using atomic pair distribution function measurements. We derived the Al-Al, O-O, and A-O atomic distances for each sample. By comparing them, werevealed that the subtle difference in the local structure significantly influences the performance ofa nonvolatile memory function.

論文

Elastic and inelastic neutron scattering experiments under high pressure in the frustrated antiferromagnet CuFeO$$_{2}$$

寺田 典樹*; Khalyavin, D. D.*; Manuel, P.*; 浅井 晋一郎*; 益田 隆嗣*; 齋藤 開*; 中島 多朗*; 長壁 豊隆

Physical Review B, 110(2), p.024406_1 - 024406_9, 2024/07

https://doi.org/10.1103/PhysRevB.110.024406
 被引用回数：0 パーセンタイル：0.00(Materials Science, Multidisciplinary)

フラストレート反強磁性体CuFeO$$_{2}$$は、圧力により、コメンシュレートなコリニアー相(CM1)からいくつかのインコメンシュレートでノンコリニアーな相への複雑な磁気相転移を示す。圧力が磁気相互作用に及ぼす影響を調べるために、高圧下で中性子回折および非弾性中性子散乱実験を行った。圧力が増すと、CM1基底状態は臨界圧力($${P}$$ $$leqq$$ 3GPa)以下でも磁場の印加に対して不安定になる。これは、2.1GPaで臨界磁場$${H_{c1}}$$が7.5Tから4.5Tに大幅に減少したことで確かめられた。さらに、スピン波分散関係のエネルギーギャップは、$$P$$=2.1GPaの圧力印加によって1.0meVから0.88meVに減少する。実験結果をスピン波計算と比較すると、スピン波励起の変化は、一軸異方性項または最近接交換相互作用の分離度のいずれかの減少によって説明できることがわかった。

論文

Single helicity of the triple-$$q$$ 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

https://doi.org/10.1103/PhysRevB.109.174437
 被引用回数：4 パーセンタイル：74.90(Materials Science, Multidisciplinary)

We investigated the magnetic helicity of the triple-$$q$$ 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-$$q$$ structure are perpendicular to the respective $$q$$ 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-$$q$$ 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.

論文

Polarized neutron diffraction study on UPt$$_{2}$$Si$$_{2}$$

今 布咲子*; 田端 千紘; 齋藤 開*; 中島 多朗*; 日高 宏之*; 柳澤 達也*; 網塚 浩*

Journal of the Physical Society of Japan, 93(4), p.044701_1 - 044701_11, 2024/04

https://doi.org/10.7566/JPSJ.93.044701
 被引用回数：0 パーセンタイル：0.00(Physics, Multidisciplinary)

We investigated the magnetic structure of the antiferromagnetic (AFM) ordered state ($$T_{rm N}$$ $$sim$$ 34 K) in tetragonal UPt$$_{2}$$Si$$_{2}$$ using polarized and unpolarized neutron diffraction. Previous neutron scattering studies reported that this system possesses a simple AFM structure with a propagation vector, Q= 0, and the ordered magnetic moments aligned along the c-axis. By contrast, our latest resonant X-ray scattering (RXS) experiments have revealed that the magnetic structure is modulated by the charge-density-wave (CDW) order, which emerges in one of the two Pt atomic layers in the unit cell below $$sim$$320 K. The modulation is characterized by a transverse wave in the c-plane, with the propagation vector of the CDW order, q$$_{rm CDW}$$ = ($$sim$$0.42, 0, 0). In this study using neutron scattering, we observed that the superlattice reflections specified by q$$_{rm CDW}$$ develop below $$T_{rm N}$$, in addition to the magnetic reflections with Q= 0, thereby further confirming the presence of modulation in the AFM structure of this system. From detailed analyses, we revealed that the amplitude of the transverse-wave magnetic modulation is 0.72(2)$$mu$$$$_{rm B}$$/U, which is quantitative information that can not be obtained through RXS experiments. This implies that the CDW drives the ordered magnetic moments to be tilted up to 20$$^{circ}$$ in the AFM state. The observations strongly suggest that the magnetism of UPt$$_{2}$$Si$$_{2}$$ is heavily influenced by the hybridization effects between the $$5f$$ electrons of U and the 5d electrons of Pt.

論文

Magnetic order in honeycomb layered U$$_2$$Pt$$_6$$Ga$$_{15}$$ 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

https://doi.org/10.1103/PhysRevB.109.134403
 被引用回数：2 パーセンタイル：40.97(Materials Science, Multidisciplinary)

Antiferromagnetic (AF) order of U$$_2$$Pt$$_6$$Ga$$_{15}$$ with the ordering temperature $$T$$$$_{rm N}$$ = 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.

論文

New standard for low temperature sample environment at JAEA/JRR-3

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

https://doi.org/10.7566/JPSCP.41.011015

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.

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