Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
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:1 パーセンタイル:63.35(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.
丸山 建一*; 田中 誠也*; 鬼柳 亮嗣; 中尾 朗子*; 森山 健太郎*; 石川 喜久*; 天児 寧*; 飯山 拓*; 二村 竜祐*; 内海 重宣*; et al.
Journal of Alloys and Compounds, 892, p.162125_1 - 162125_8, 2022/02
Hexagonal ferrite Ba(FeSc
)
O
is an important magnetic oxide material in both science and engineering because it exhibits helimagnetism around room temperature (300 K). In this study, the magnetic phase diagram of Ba(Fe
Sc
)
O
consisting of ferri-, heli-, antiferro-, and paramagnetic phases has been completed through magnetization and neutron diffraction measurements. The magnetic phase transition temperature to paramagnetism decreases with the increase in x, and the temperature at which the magnetization reaches a maximum, which corresponds to the magnetic phase transition from heli- to ferrimagnetism, is determined for low x crystals. The temperatures at which helimagnetism appears are precisely determined by observing the magnetic satellite reflection peaks in neutron diffraction at various temperatures, which characterize helimagnetism. Based on these results, the magnetic phase diagram of the Ba(Fe
Sc
)
O
system is constructed in the T-x plane. Helimagnetism appears at x
0.06, and magnetism with antiferromagnetic components appears as the extension phase of helimagnetism at x
0.19 through the coexistence region. The turn angle
of the helix for each x crystal is calculated from the relationship,
, where
is the incommensurability. The turn angle
decreases with the increase in temperature for the same x crystal, and increases with the increase in x at the same temperature. Furthermore, it is found that there are clear thresholds at which
cannot take values between 0
<
< 90
and 170
<
< 180
.
金子 耕士; 川崎 卓郎; 仲村 愛*; 宗像 孝司*; 中尾 朗子*; 花島 隆泰*; 鬼柳 亮嗣; 大原 高志; 辺土 正人*; 仲間 隆男*; et al.
Journal of the Physical Society of Japan, 90(6), p.064704_1 - 064704_6, 2021/06
被引用回数:23 パーセンタイル:95.74(Physics, Multidisciplinary)Multiple transition phenomena in divalent Eu compound EuAl with the tetragonal structure were investigated via single crystal time-of-flight neutron Laue technique. At 30 K below a charge-density-wave (CDW) transition, superlattice peaks emerge near nuclear Bragg peaks described by an ordering vector
= (0 0
). In contrast, magnetic peaks appear at
with
= 0.09 below
= 15.4 K, and moves to
with
= 0.19 below
=12.2 K, whereas no distinct change in the magnetic Bragg peak was detected at
and
. The structural modification with
is characterized by an absence of the superlattice peak in (0 0
). Considering an absence of splitting in magnetic peaks along
, the structural transition is mainly ascribed to a displacement of Al ions within the tetragonal
-plane. Complex incommensurate magnetic transitions are in stark contrast to a simple collinear commensurate structure in isovalent EuGa
. This could stem from incompatible electronic structures with the CDW transition between two compounds.
Kwon, H.*; Pietrasiak, E.*; 大原 高志; 中尾 朗子*; Chae, B.*; Hwang, C.-C.*; Jung, D.*; Hwang, I.-C.*; Ko, Y. H.*; Kim, K.*; et al.
Inorganic Chemistry, 60(9), p.6403 - 6409, 2021/05
被引用回数:0 パーセンタイル:0.01(Chemistry, Inorganic & Nuclear)The synthesis of sandwich-shaped multinuclear silver complexes with planar penta- and tetranuclear wheel-shaped silver units and a central anion is reported, along with complete spectroscopic and structural characterization. An NMR mechanistic study reveals that silver complexes were formed in the following order: 2Ag 3Ag
5Ag
4Ag
. The central hydroxides in 4Ag
and 5Ag
exhibit exotic physical properties due to the confined environment inside the complex. The size of these silver wheels can be tuned by changing the central anion or extracting/adding one silver atom. This study provides the facile way to synthesize discrete wheel-shaped multinuclear silver complexes and provides valuable insights into the dynamics of the self-assembly process.
矢島 健*; 日沼 洋陽*; 堀 智*; 岩崎 類*; 菅野 了次*; 大原 高志; 中尾 朗子*; 宗像 孝司*; 廣井 善二*
Journal of Materials Chemistry A, 9(18), p.11278 - 11284, 2021/05
被引用回数:10 パーセンタイル:79.18(Chemistry, Physical)Herein, we studied the crystalline compound LiGeP
S
with the largest Li-ion conductivity thus far via a novel route based on a combination of single-crystal neutron diffraction experiments at low temperature and first-principles calculations, and found that a correlated migration of the densely packed Li ions governs the overall Li-ion conduction. The correlated migration mechanism provides us with guidelines on how to design efficient superionic conductors for more efficient batteries.
山口 瑛子; 浅野 育美*; 北川 結理*; Meng, C.*; 中尾 淳*; 奥村 雅彦
Proceedings of Joint International Conference on Supercomputing in Nuclear Applications + Monte Carlo 2020 (SNA + MC 2020), p.127 - 130, 2020/10
粘土鉱物は身近な鉱物の一つであり、環境中の元素挙動に大きな影響を及ぼすにも関わらず、未解明な点が多い。粘土鉱物の重要な特性の一つに、同程度の大きさのイオンによる置換反応(同形置換)があり、粘土鉱物の強い吸着力の要因の一つと考えられているが、実際にどの程度影響を及ぼすか評価されたことはない。本発表では、系統的なモデル作成と第一原理計算を用いることで、同形置換が剥離強度に与える影響を数値的に評価した結果を報告する。
内海 重宣*; 田中 誠也*; 丸山 建一*; 天児 寧*; 鬼柳 亮嗣; 中尾 朗子*; 森山 健太郎*; 石川 喜久*; 他9名*
ACS Omega (Internet), 5(38), p.24890 - 24897, 2020/09
六方晶フェライトBa(FeSc
)
O
の磁気構造を解明し、さらなる応用開発を進めるためには、大型の高品質な単結晶を育成することが重要な第一歩である。本研究では、Na
O-Fe
O
フラックスを使用した自発結晶化法によって、さまざまなSc濃度
のBa(Fe
Sc
)
O
単結晶の育成に成功した。得られた結晶は、高品質の単相Ba(Fe
Sc
)
O
であることがX線回折と元素分析により確認され、
= 0.128結晶の77Kの磁化測定では、ヘリマグネティックな挙動を示すことがわかった。
=0.128結晶の中性子回折測定の結果、211K以下で磁気衛星反射が確認され、Ba(Fe
Sc
)
O
がヘリ磁性物質であることが確認された。
飯田 一樹*; 吉田 紘行*; 中尾 朗子*; Jeschke, H. O.*; Iqbal, Y.*; 中島 健次; 河村 聖子; 宗像 孝司*; 稲村 泰弘; 村井 直樹; et al.
Physical Review B, 101(22), p.220408_1 - 220408_6, 2020/06
被引用回数:18 パーセンタイル:85.16(Materials Science, Multidisciplinary)鉱物センテニアライトCaCu(OD)
Cl
0.6D
Oの結晶構造と磁気構造をシンクロトロンX線回折と中性子回折測定に密度汎関数理論(DFT)と疑似フェルミオン汎関数繰り込み群(PFFRG)の計算を組み合わせることで調べた。CaCu
(OD)
Cl
0.6D
OではCu
イオンは反強磁性
と幾何学的に完全なカゴメネットワークを形成する。Cu
とCa
イオン間のサイト間無秩序は見つからなかった。CaCu
(OD)
Cl
0.6D
Oは
=7.2K以下で磁気秩序を示し、負のベクトルスピンキラリティーを持つ
=0の磁気構造が現れる。0.3Kでの秩序モーメントは0.58(2)
Bに抑えられている。我々のDFT計算では、この系が量子臨界点の近くにあり、
-
-
カゴメ反強磁性体の優れた実現であることを示唆している。
Hirschberger, M.*; 中島 多朗*; Kriener, M.*; 車地 崇*; Spitz, L.*; Gao, S.*; 吉川 明子*; 山崎 裕一*; 佐賀山 基*; 中尾 裕則*; et al.
Physical Review B, 101(22), p.220401_1 - 220401_6, 2020/06
被引用回数:28 パーセンタイル:92.13(Materials Science, Multidisciplinary)For the skyrmion-hosting intermetallic GdPdSi
with centrosymmetric hexagonal lattice and triangular net of rare earth sites, we report a thorough investigation of the magnetic phase diagram. Our work reveals a magnetic phase with an isotropic value of the critical field for all orientations, where the magnetic ordering vector
is depinned from its preferred directions in the basal plane. The bulk nature of the skyrmion lattice and of other magnetic phases was evidenced by specific-heat measurements. Resistivity anisotropy, likely originating from partial gapping of the density of states along
in this Ruderman-Kittel-Kasuya-Yoshida magnet, is picked up via the planar Hall effect (PHE). The PHE confirms the single-
nature of the magnetic order when the field is in the hexagonal plane, and allows one to detect the preferred directions of
. Several scenarios for the depinned phase are discussed on the basis of the data.
阿部 伸行*; 塩澤 俊介*; 松浦 慧介*; 佐賀山 基*; 中尾 朗子*; 大原 高志; 徳永 祐介*; 有馬 孝尚*
Physical Review B, 101(18), p.180407_1 - 180407_5, 2020/05
被引用回数:2 パーセンタイル:18.66(Materials Science, Multidisciplinary)The correlation between magnetism and electric polarization in a chiral insulating magnet BaFe
O
Cl
has been investigated. The temperature dependence of magnetic susceptibility shows an anomaly at 564 K, suggesting the onset of antiferromagnetic order of Fe
moments. Electric polarization appears in a magnetic field below TN due to the spin-direction-dependent metal-ligand hybridization. The direction of the electric polarization can be controlled in three-dimensional space by changing the direction of an external magnetic field. This compound also shows an antiferromagnetic-to-weak-ferromagnetic transition accompanied by a structural phase transition at 140 K.
中里 晟也*; 岩佐 和晃*; 橋本 大輔*; 塩澤 真未*; 桑原 慶太郎*; 中尾 裕則*; 佐賀山 基*; 石角 元志*; 大原 高志; 中尾 朗子*; et al.
JPS Conference Proceedings (Internet), 30, p.011128_1 - 011128_6, 2020/03
Successive phase transitions of Ir
Sn
(
: La and Ce) were studied using neutron and X-ray diffraction techniques. A semimetal Ce
Ir
Sn
undergoes three phase transitions: an antiferromagnetic ordering characterized by a propagation vector
= (1/2, 1/2, 2/5) below 0.6 K, a structural transformation with
= (1/4, 1/4, 1/4) at 2.0 K, and another structural transformation with
= (1/2, 1/2, 0) above room temperature. La
Ir
Sn
was confirmed to be a superconductor below 2.5 K under the
= (1/2, 1/2, 0) structure that also appears above room temperature.
池田 修悟*; 金子 耕士; 田中 佑季*; 川崎 卓郎; 花島 隆泰*; 宗像 孝司*; 中尾 朗子*; 鬼柳 亮嗣; 大原 高志; 望月 健生*; et al.
Journal of the Physical Society of Japan, 89(1), p.014707_1 - 014707_7, 2020/01
被引用回数:0 パーセンタイル:0(Physics, Multidisciplinary)Magnetism in EuNiIn has been studied by specific heat, magnetic susceptibility, magnetization,
Eu M
ssbauer spectroscopy, and neutron diffraction experiments. The specific heat shows two magnetic transitions at
and
at zero magnetic field. An antiferromagnetic ground state of EuNiIn
has a uniaxial magnetic anisotropy along the b-axis, revealed by the magnetic susceptibility and the M
ssbauer spectroscopy. Single crystal neutron diffraction experiments clarify that this antiferromagnetic structure in the ground state is characterized by the commensurate propagation vector
= (1/2, 1/2, 1/2) which reveals no distinct anomaly at
. The magnetization curve along the b-axis at 2 K shows four successive magnetic field-induced transitions up to 50 kOe and, reaches 7
/f.u. above 190 kOe, The magnetic phase diagram in EuNiIn
has unique characteristics with five magnetic states in low magnetic field.
中根 僚宏*; 米山 翔太*; 兒玉 健*; 菊地 耕一*; 中尾 朗子*; 大原 高志; 東中 隆二*; 松田 達磨*; 青木 勇二*; 藤田 渉*
Dalton Transactions (Internet), 48(1), p.333 - 338, 2019/01
被引用回数:2 パーセンタイル:14.83(Chemistry, Inorganic & Nuclear)The two-dimensional quadratic lattice magnet, bis(glycolato)cobalt(II) ([Co(HOCHCO
)
]), showed anti-ferromagnetic ordering at 15.0 K and an abrupt increase in magnetisation at H = 22 600 Oe and 2 K, thereby acting as a metamagnet. Neutron diffraction studies suggested that the magnetic moment vectors of the Co(II) ions had an amplitude of 3.59 mB and were not aligned in a fully antiparallel fashion to those of their neighbours, which caused canting between the magnetic moment vectors in the sheet. The canting angle was determined to be 7.1deg. Canting induced net magnetisation in the sheet, but this magnetisation was cancelled between sheets. The magnetisations in the sheets were oriented parallel to the magnetic field at the critical magnetic field.
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:50 パーセンタイル:95.2(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.
岩佐 和晃*; 伊賀 文俊*; 茂吉 武人*; 中尾 朗子*; 大原 高志
Journal of the Physical Society of Japan, 87(6), p.064705_1 - 064705_5, 2018/06
被引用回数:0 パーセンタイル:0(Physics, Multidisciplinary)The magnetic-ordered state of a single-crystal sample of TbB has been studied with the high-precision neutron diffraction instrument SENJU installed at BL18 of the Materials and Life Science Facility in J-PARC. We observed new Bragg-reflection spots characterized by a propagation vector
= (1/4, 1/4, 0) below the N
el temperature
20 K, in addition to the
= (1/4, 1/4. 1/2) reported in the previous literatures. Because X-ray Thomson scattering measurements do not detect the
superlattice reflections at 13 K,
is a new magnetic-ordering propagation vector. The magnetic multi-q structure of TbB
is similar to that of CeB
, whereas the ratio of the
amplitude to that of qM1 is smaller than in CeB
. The combination of
and
is expected to assist the
= (1/2, 0, 0) lattice modulation.
土屋 朋生*; 小林 亮太*; 窪田 崇秀*; 斉藤 耕太郎*; 小野 寛太*; 大原 高志; 中尾 朗子*; 高梨 弘毅*
Journal of Physics D; Applied Physics, 51(6), p.065001_1 - 065001_7, 2018/02
被引用回数:6 パーセンタイル:35.17(Physics, Applied)MnVAl Heusler alloy films were epitaxially grown on MgO(100) single-crystal substrates by ultra-high-vacuum magnetron sputtering. A2- and L21-type Mn
VAl order was controlled by the deposition temperature. A2-type Mn
VAl films showed no spontaneous magnetization, while L21-type Mn
VAl films showed ferrimagnetic behaviour with a maximum saturation magnetization of 220 emu/cm
at room temperature (RT). An antiferromagnetic reflection was observed with neutron diffraction at RT for an A2-type Mn
VAl film deposited at 400
C. A bilayer sample of the antiferromagnetic A2-type Mn
VAl and Fe showed an exchange bias of 120 Oe at 10 K.
社本 真一; 伊藤 孝; 大西 弘明; 山内 宏樹; 稲村 泰弘; 松浦 直人*; 赤津 光洋*; 樹神 克明; 中尾 朗子*; 茂吉 武人*; et al.
Physical Review B, 97(5), p.054429_1 - 054429_9, 2018/02
被引用回数:15 パーセンタイル:63.41(Materials Science, Multidisciplinary)イットリウム鉄ガーネットの核および磁気構造と全マグノン分散を中性子散乱により調べた。低エネルギーの分散は強磁性マグノンで期待されるように14meVまで2次関数の分散を示した。積分した動的磁化率
"(
)の虚部は低エネルギーで平方根のエネルギー依存性を示した。
"(
)から絶対値でマグノン状態密度を求めた。その値は理論的に予想されるマグノン分散でひとつのカラリティーモードに対応する。
中島 健次; 川北 至信; 伊藤 晋一*; 阿部 淳*; 相澤 一也; 青木 裕之; 遠藤 仁*; 藤田 全基*; 舟越 賢一*; Gong, W.*; et al.
Quantum Beam Science (Internet), 1(3), p.9_1 - 9_59, 2017/12
J-PARC物質・生命科学実験施設の中性子実験装置についてのレビューである。物質・生命科学実験施設には23の中性子ビームポートがあり21台の装置が設置されている。それらは、J-PARCの高性能な中性子源と最新の技術を組み合わせた世界屈指の実験装置群である。このレビューでは、装置性能や典型的な成果等について概観する。
五十嵐 正安*; 松本 朋浩*; 八木橋 不二夫*; 山下 浩*; 大原 高志; 花島 隆泰*; 中尾 朗子*; 茂吉 武人*; 佐藤 一彦*; 島田 茂*
Nature Communications (Internet), 8, p.140_1 - 140_8, 2017/07
被引用回数:21 パーセンタイル:63.15(Multidisciplinary Sciences)Orthosilicic acid (Si(OH)) and its small condensation compounds are among the most important silicon compounds but have never been isolated, despite the long history of intense research due to their instability. These compounds would be highly useful building blocks for advanced materials if they become available at high purity. We developed a simple procedure to selectively synthesize orthosilicic acid, its dimer, cyclic trimer, and tetramer, as well as appropriate conditions to stabilize these species, in organic solvents. Isolation of orthosilicic acid, the dimer and the cyclic tetramer as hydrogen-bonded crystals with tetrabutylammonium halides and of the cyclic trimer as solvent-containing crystals was achieved. The solid-state structures of these compounds were unambiguously clarified by single crystal X-ray diffraction analysis and also by neutron diffraction study for orthosilicic acid. Based on these results, we also succeeded in developing a more practical synthetic procedure for high concentrations of stable orthosilicic acid stably in organic solvents via a simple hydrolysis of tetraalkoxysilanes.
川崎 卓郎; 金子 耕士; 仲村 愛*; 阿曽 尚文*; 辺土 正人*; 仲間 隆男*; 大原 高志; 鬼柳 亮嗣; 及川 健一; 田村 格良; et al.
Journal of the Physical Society of Japan, 85(11), p.114711_1 - 114711_5, 2016/11
被引用回数:8 パーセンタイル:55.05(Physics, Multidisciplinary)The magnetic structure of the intermetallic compound EuGa was investigated using single-crystal neutron diffraction with TOF Laue technique on the new diffractometer SENJU at MLF of J-PARC. Despite of the high neutron absorption of Eu, a vast number of diffraction spots were observed without isotope enrichment. The magnetic reflections appeared at
2
below 16 K, indicating that the ordering vector is
= (0, 0, 0). The continuous evolution of the magnetic reflection intensity below T
follows a squared Brillouin function for
= 7/2. By adopting a wavelength-dependent absorption collection, the magnetic structure of EuGa
revealed that a nearly full magnetic moment of 6.4
B of Eu lies within the basal plane of the lattice.