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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：3 パーセンタイル：46.22(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.
松村 武*; 塚越 舜*; 上田 祥央*; 比嘉 野乃花*; 中尾 朗子*; 金子 耕士; 垣花 将司*; 辺土 正人*; 仲間 隆男*; 大貫 惇睦*
Journal of the Physical Society of Japan, 91(7), p.073703_1 - 073703_5, 2022/07
被引用回数：8 パーセンタイル：72.05(Physics, Multidisciplinary)Successive magnetic phase transitions in EuIrGe, an intermetallic compound with a body centered tetragonal lattice belonging to a polar space group I4mm, has been investigated by neutron diffraction and resonant X-ray diffraction. It is shown that EuIrGe exhibits an incommensurate longitudinal sinusoidalorder with 
(0, 0, 0.792) and m
c-axis in the high temperature phase, which changes to a cycloidal order with = (
, 0, 0.8) (
0.017) and m ac-plane in the intermediate phase. In the low temperature phase, the cycloidal plane rotates by 45
to have =(
, 0.8) (
0.012). It is also pointed out that the X-ray scattering amplitude from odd-parity magnetic quadrupole due to the polar environment interfere with that from normal even-parity magnetic dipole in the magnetic ordered phase.
SR and NMR studies比嘉 野乃花*; 伊藤 孝; 與儀 護*; 服部 泰佑; 酒井 宏典; 神戸 振作; Guguchia, Z.*; 髭本 亘; 中島 美帆*; 本間 佳哉*; et al.
Physical Review B, 104(4), p.045145_1 - 045145_7, 2021/07
被引用回数：4 パーセンタイル：18.02(Materials Science, Multidisciplinary)We report the results of SR and 
Si NMR measurements carried out on the cubic chiral magnet EuPtSi. Our zero-field SR experiments revealed the development of critical slowing down of Eu spin fluctuations over a relatively wide critical region above 
. We also found from Si NMR that the spin fluctuations are strongly suppressed by magnetic field in the paramagnetic state above 20K. These characteristic spin dynamics observed over a wide region of temperature and magnetic field suggest the presence of magnetic frustration in the spin system. Such frustration would underlie the mechanism stabilizing the short-period skyrmion lattice observed in this compound.
2
3の空間群に属する化合物および関連する化合物の結晶構造について垣花 将司*; 竹内 徹也*; 芳賀 芳範; 播磨 尚朝*; 辺土 正人*; 仲間 隆男*; 大貫 惇睦*
固体物理, 55(10), p.505 - 514, 2020/10
立方晶キラル構造に属する磁性体が示す特異な磁気相が注目されている。代表的な物質MnSi(空間群23)および関連物質の構造の特徴を分類するとともに、一見複雑に見える結晶構造を安定化させる要因について考察する。
金子 耕士; 垣花 将司*; 辺土 正人*; 仲間 隆男*; 大貫 惇睦*
波紋, 30(3), p.160 - 165, 2020/08
MnSiと同じ空間群に属する4
電子系化合物EuPtSiについて、磁気特性を調べた。単結晶中性子回折実験の結果、MnSiとEuPtSiの磁気構造に多くの共通点を見出した。この結果は、EuPtSiが4電子系で初めて磁気スキルミオン格子を示す物質であることを示している。
大貫 惇睦*; 垣花 将司*; 伊覇 航*; 仲井間 憲李*; 青木 大*; 仲村 愛*; 本多 史憲*; 中島 美帆*; 天児 寧*; 郷地 順*; et al.
JPS Conference Proceedings (Internet), 29, p.012001_1 - 012001_9, 2020/02
EuPtSi with the cubic chiral structure exhibits a skyrmion phase under magnetic field. We succeeded in growing high-quality single crystals by the Bridgman method. Fermi surface splitting reflecting the noncentrosymmetric structure was successfully observed experimentally.
電子系化合物EuPtSiにおける磁気スキルミオン金子 耕士; 垣花 将司*; 辺土 正人*; 仲間 隆男*; 大貫 惇睦*
固体物理, 54(12), p.757 - 766, 2019/12
MnSiと同じ空間群に属する4電子系化合物EuPtSiについて、磁気特性を調べた。単結晶中性子回折実験の結果、MnSiとEuPtSiの磁気構造に多くの共通点を見出した。この結果は、EuPtSiが4電子系で初めて磁気スキルミオン格子を示す物質であることを示している。
magnetic order in trillium lattice antiferromagnet EuPtSi studied by resonant X-ray scattering田端 千紘*; 松村 武*; 中尾 裕則*; 道村 真司*; 垣花 将司*; 稲見 俊哉*; 金子 耕士; 辺土 正人*; 仲間 隆男*; 大貫 惇睦*
Journal of the Physical Society of Japan, 88(9), p.093704_1 - 093704_5, 2019/09
被引用回数：43 パーセンタイル：87.71(Physics, Multidisciplinary)The magnetic order in the magnetic-fild-induced so-called A phase of cubic chiral antiferromagnet EuPtSi was investigated by resonant X-ray scattering (RXS) near the Eu 
edge. The high flux RXS signal under the magnetic field applied along [111] revealed the first and second order satellite magnetic reflections, indicating that the A phase is a triple- magnetic ordered state that is described by three propagation vectors lying in the plane normal to the magnetic field direction; 
, 
, and 
. With the high resolution in the reciprocal space achieved in the RXS measurement, it is suggested that the triple- order strongly couples with the underlying crystal lattice. The triple- magnetic order is discussed in the context of a magnetic skyrmion lattice on which the geometrical frustration may play a crucial role.
Eu M
ssbauer spectroscopy本間 佳哉*; 垣花 将司*; 徳永 陽; 與儀 護*; 中島 美帆*; 仲村 愛*; 清水 悠晴*; Li, D.*; Maurya, A.*; 佐藤 芳樹*; et al.
Journal of the Physical Society of Japan, 88(9), p.094702_1 - 094702_8, 2019/08
被引用回数：10 パーセンタイル：57.42(Physics, Multidisciplinary)We report the results of Eu Mssbauer spectroscopy on EuPtSi with a chiral structure belonging to the P2
3 space group at zero magnetic field. The paramagnetic single absorption forms a magnetic splitting profile directly below 4.0 K and the spectrum at 3.9 K consists of the sum of the paramagnetic single absorption and the magnetic splitting absorption, which indicates a first-order transition at 4.0 K. The temperature dependence of the effective hyperfine fields at the Eu nucleus follows a power law indicates a full moment of Eu
ions.
伊覇 航*; 垣花 将司*; 松田 進弥*; 本多 史憲*; 芳賀 芳範; 竹内 徹也*; 中島 美帆*; 天児 寧*; 郷地 順*; 上床 美也*; et al.
Journal of Alloys and Compounds, 788, p.361 - 366, 2019/06
被引用回数：11 パーセンタイル：46.44(Chemistry, Physical)Ferromagnetic ordering of EuCuP is investigated on a single crystal sample grown from tin flux. Application of hydrostatic pressure up to 8 GPa stabilizes ferromagnetic ordering, suggesting divalent Eu is stable. The Hall effect and resistivity measurements show that EuCuP is a low-carrier ferromagnetic metal with a characteristic resistivity cusp appearing at the ferromagnetic transition temperature.
垣花 将司*; 西村 憲吾*; 竹内 徹也*; 芳賀 芳範; 播磨 尚朝*; 辺土 正人*; 仲間 隆男*; 大貫 惇睦*
Journal of the Physical Society of Japan, 88(4), p.044712_1 - 044712_11, 2019/04
被引用回数：4 パーセンタイル：32.58(Physics, Multidisciplinary)Fermi surfaces of semimetallic YSb, LuSb, YBi and LuBi were investigated by de Haas-van Alphen effect. The Fermi surfaces consist of hole pockets arising from 
-bands from Sb or Bi and electron ellipsoids from 5
band of Y or Lu. Larger carrier number of YBi and LuBi is attributed to larger spin-orbit interaction of Bi-6 state than Sb-5.
金子 耕士; Frontzek, M. D.*; 松田 雅昌*; 中尾 朗子*; 宗像 孝司*; 大原 高志; 垣花 将司*; 芳賀 芳範; 辺土 正人*; 仲間 隆男*; et al.
Journal of the Physical Society of Japan, 88, p.013702_1 - 013702_5, 2019/01
被引用回数：75 パーセンタイル：94.53(Physics, Multidisciplinary)Magnetic transitions in chiral antiferromagnet EuPtSi were investigated by means of single crystal neutron diffraction. In the ground state, magnetic peaks emerge at positions represented by 
=
. Upon heating, an additional magnetic peak splitting around 2.5 K was uncovered, indicating a presence of a first-order transition with 
=
. An half-polarized neutron scattering for polarization parallel to Q reveled that polarization antiparallel to Q has stronger intensity in both magnetic phases. This feature clarifies single chiral character of helical structure with moments normal to the ordering vector in both ordered states. Under vertical magnetic field along [1,1,1] in the 
phase, magnetic peaks form hexagonal patterns in the equatorial scattering plane around nuclear. An ordering vector 
of the -phase has the similar size in the periodicity to , and could be a hallmark of a formation of skyrmion lattice in EuPtSi.
Si竹内 徹也*; 屋良 朝之*; 安次富 洋介*; 伊覇 航*; 垣花 将司*; 中島 美帆*; 天児 寧*; 本多 史憲*; 本間 佳哉*; 青木 大*; et al.
Journal of the Physical Society of Japan, 87(7), p.074709_1 - 074709_14, 2018/07
被引用回数：13 パーセンタイル：63.33(Physics, Multidisciplinary)Effects of magnetic field and pressure on the Kondo-like behavior in the valence-fluctuating antiferromagnetic compound EuPtSi were studied using single-crystalline samples. Anomalous features in EuPtSi are due to valence fluctuation and/or valence change of the Eu ions at low temperatures.
(Ge
Si
) based on the doniach phase diagram伊覇 航*; 屋良 朝之*; 安次富 洋介*; 垣花 将司*; 竹内 徹也*; 本多 史憲*; 仲村 愛*; 青木 大*; 郷地 順*; 上床 美也*; et al.
Journal of the Physical Society of Japan, 87(6), p.064706_1 - 064706_14, 2018/06
被引用回数：19 パーセンタイル：72.20(Physics, Multidisciplinary)We succeeded in growing single crystals of the series of EuCu(GeSi) compounds.Physical property measurements demonstrate a maximum of the antiferromagnetic transition temperature appears at 
. Antiferromagnetism then disappears around 
followed by a heavy-fermion formation at higher concentrations. These observations follow the Doniach phase diagram as a function of 
.
Co照屋 淳志*; 垣花 将司*; 竹内 徹也*; 青木 大*; 本多 史憲*; 仲村 愛*; 芳賀 芳範; 松林 和幸*; 上床 美也*; 播磨 尚朝*; et al.
Journal of the Physical Society of Japan, 85(3), p.034706_1 - 034706_10, 2016/03
被引用回数：9 パーセンタイル：53.05(Physics, Multidisciplinary)Superconducting characteristics and Fermi surfaces of ZrCo are experimentally studied on a single crystal sample grown by Bridgman technique. Thermodynamic quantities in the superconducting state such as specific heat and magnetization show deviation from a single-gap the BCS model and can be attributed on the band structure with the dominant contribution of Zr-4 and Co-3 components.
垣花 将司*; 照屋 淳志*; 西村 憲吾*; 仲村 愛*; 竹内 徹也*; 芳賀 芳範; 播磨 尚朝*; 辺土 正人*; 仲間 隆男*; 大貫 惇睦
Journal of the Physical Society of Japan, 84(9), p.094711_1 - 094711_8, 2015/09
被引用回数：17 パーセンタイル：69.05(Physics, Multidisciplinary)Fermi surface properties of illuminate NiSbS and PbBiSe have been clarified by de Haas-van Alphen effect, resistivity and specific heat measurements. Fermi surfaces were found to split into two, reflecting the non-centrosymmetric crystal structure. The splitting energies have been estimated experimentally. Those are originated from spin-orbit interactions.
-electron magnet EuPtSi金子 耕士; 田端 千紘*; 竹内 徹也*; Frontzek, M. D.*; 松田 雅昌*; 大石 一城*; 伊藤 孝; 宗像 孝司*; 鬼柳 亮嗣; 垣花 将司*; et al.
no journal, ,
Magnetic skyrmion, particle-like topologically non-trivial spin textures, attracts surge of interests from both fundamental and application points of view. Since the first discovery in MnSi crystallizing in the cubic space group 
, intensive research on magnetic skyrmions has conducted for materials particularly in this space group. This leads to findings of new class of materials, whereas magnetic ions were mostly limited to d electron systems. Recently, it turned out that f-electron compounds can host magnetic skyrmion lattice as well. The magnetic skyrmions in f-electron compounds possess contrasting characteristics, such as short periodicity and strong anisotropy. Among recent discoveries, cubic chiral compound EuPtSi provides ideal opportunities to compare with d-electron systems as it crystallizes in the same space group as MnSi, namely . We will present our neutron and X-ray scattering studies to characterize magnetic skyrmion lattice in this compound.
金子 耕士; Frontzek, M. D.*; 松田 雅昌*; 中尾 朗子*; 宗像 孝司*; 大原 高志; 垣花 将司*; 芳賀 芳範; 辺土 正人*; 仲間 隆男*; et al.
no journal, ,
空間群に属する空間反転対称性を持たない立方晶化合物EuPtSiでは、Euイオンは2価の安定状態で7
Bの大きなモーメントを持ち、比較的低温の=4.0Kで反強磁性秩序を示す。磁場により中間温度領域にのみ誘起される、MnSiのスキルミオン相と類似した特徴的な磁場誘起相が現れること、その秩序相内でホール抵抗の増大が観測されていることから、高い注目を集めている。本研究では、磁気構造を明らかにすることを目的として単結晶中性子回折を行い、ゼロ磁場ではキラリティーを有する特徴的な磁気構造を持つこと、秩序相内で新たな転移の存在などを明らかにした。その詳細について報告する。
金子 耕士; 田端 千紘*; 大石 一城*; 伊藤 孝; 中尾 裕則*; Frontzek, M. D.*; 松田 雅昌*; 宗像 孝司*; 中尾 朗子*; 大原 高志; et al.
no journal, ,
MnSiと同じ空間群に属する立方晶化合物EuPtSiでは、有限磁場・温度領域でのみ安定化する特徴的な磁場誘起秩序相であるA相が現れ、輸送特性, 中性子, X線回折から、磁気スキルミオン格子が実現していることが確認された。MnSiの磁気スキルミオン相と比べ、EuPtSi固有の特徴の一つは、強い異方性をもつことである。この点について、磁場中中性子散乱で調べた微視的な構造変化を報告する。
金子 耕士; 田端 千紘*; 大石 一城*; 伊藤 孝; 中尾 裕則*; Frontzek, M. D.*; 松田 雅昌*; 宗像 孝司*; 中尾 朗子*; 大原 高志; et al.
no journal, ,
MnSiと同じ空間群に属する立方晶化合物EuPtSiでは、有限磁場・温度領域でのみ安定化する特徴的な磁場誘起秩序相であるA相が現れ、輸送特性, 中性子, X線回折から、磁気スキルミオン格子が実現していることが確認された。MnSiの磁気スキルミオン相と比べ、EuPtSi固有の特徴の一つは、強い異方性をもつことである。この点について、磁場中中性子散乱で調べた微視的な構造変化を報告する。
