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Zn
and UCoZn広瀬 雄介*; 竹内 徹也*; 本多 史憲*; 吉内 伸吾*; 萩原 政幸*; 山本 悦嗣; 芳賀 芳範; 摂待 力生*; 大貫 惇睦
Journal of the Physical Society of Japan, 84(7), p.074704_1 - 074704_10, 2015/07
被引用回数：6 パーセンタイル：45.13(Physics, Multidisciplinary)Magnetic phase diagram of two heavy fermion metamagnets UIrZn and UCoZn is investigated. UIrZn shows a reconstruction of the electronic states across the metamagnetic crossover. However, UCoZn shows a rather continuous evolution. The remarkable difference in both compounds can be accounted for by different degree of hybridization between 5
and ligand electrons.
Zn (T: Rh and Ir)本多 史憲*; 広瀬 雄介*; 三宅 厚志*; 水牧 仁一朗*; 河村 直己*; 筒井 智嗣*; 綿貫 徹; 渡辺 真仁*; 竹内 徹也*; 摂待 力生*; et al.
Journal of Physics; Conference Series, 592(1), p.012021_1 - 012021_5, 2015/03
被引用回数：3 パーセンタイル：72.07(Physics, Atomic, Molecular & Chemical)重い電子系化合物YbTZn(T: Rh and Ir)について、X線吸収分光法によりYb価数観察を行った。いずれの化合物でもYb価数は温度依存性を示し、約100K以下で冷却とともにYb価数が減少する変化が見られた。これは、同型化合物であるYbCoZnにおいて温度依存性が見られないこととは対照的な結果である。
Zn金子 耕士; Raymond, S.*; Ressouche, E.*; Lapertot, G.*; 竹内 徹也*; 広瀬 雄介*; 本多 史憲*; 大貫 惇睦
JPS Conference Proceedings (Internet), 3, p.011061_1 - 011061_5, 2014/06
YbCoZn has a heavy-fermion ground state with an enormously large Sommerfeld coefficient of 8 J/molK
, and that is sensitive to external fields. Whereas pressure induces antiferromagnetic order, magnetic field induces metamagnetic transitions around 0.5 T, and new ordered state appears above 6 T for 
. In order to get insights into electronic states and its magnetic field response, neutron scattering experiments on single crystalline samples were carried. In a field-induced phase, magnetic reflections were successfully observed, which has a different propagation vector to that of pressure induced phase. Inelastic neutron scattering probes a crystal-field excitation at a low excitation energy which overlaps to quasielastic response. The results suggest degenerated energy scale, and that leads to variety of external response in YbCoZn.
and EuAl仲村 愛*; 平仲 裕一*; 辺土 正人*; 仲間 隆男*; 三浦 泰直*; 堤 泰樹*; 森 晶宣*; 石田 一裕*; 三田村 勝哉*; 広瀬 雄介*; et al.
JPS Conference Proceedings (Internet), 3, p.011012_1 - 011012_6, 2014/06
Two europium compounds with the same structure EuGa and EuAl have been investigated. The Fermi surfaces revealed experimentally show a peculiar feature: flat Fermi surface sheets appear parallel to the tetragonal [110] planes. Reflecting this, a charge density wave transition due to the nesting of Fermi surface sheets has been observed in EuAl.
Zn (T: Co, Ir)広瀬 雄介*; 竹内 徹也*; 吉内 伸吾*; 山本 悦嗣; 芳賀 芳範; 摂待 力生*; 大貫 惇睦
JPS Conference Proceedings (Internet), 3, p.011056_1 - 011056_6, 2014/06
Transport properties of UTZn (T: Co, Ir) have been investigated by measuring Hall effect. Overall behavior is explained by the skew scattering on the impurity model at high temperatures and the periodic Anderson model at low temperatures. Rather complicated behavior was observed in UIrZn with ferromagnetic instability, implying the electronic modification under magnetic field.
仲村 愛*; 平仲 裕一*; 辺土 正人*; 仲間 隆男*; 立津 慶幸*; 眞榮平 孝裕*; 三浦 泰直*; 森 晶宣*; 堤 泰樹*; 広瀬 雄介*; et al.
Journal of the Physical Society of Japan, 82(12), p.124708_1 - 124708_6, 2013/12
被引用回数：21 パーセンタイル：72.49(Physics, Multidisciplinary)Fermi surfaces and magnetic properties of an antiferromagnet EuBi were investigated on a flux-grown single crystal. A critical magnetic field of 225 kOe where the magnetic moments are forced to align ferromagnetically was well explained by the magnetic exchange interaction based on a two-sublattice model. The Fermi surface characteristics are in agreement with the theoretical prediction indicating a fully magnetic divalent state in Eu atoms.
仲村 愛*; 平仲 裕一*; 辺土 正人*; 仲間 隆男*; 三浦 泰直*; 堤 泰樹*; 森 晶宣*; 石田 一裕*; 三田村 勝哉*; 広瀬 雄介*; et al.
Journal of the Physical Society of Japan, 82(10), p.104703_1 - 104703_10, 2013/10
被引用回数：34 パーセンタイル：82.04(Physics, Multidisciplinary)High quality single crystals of EuGa have been grown from Ga flux. Electrical resistivity, magnetic susceptibility, high-field magnetization, specific heat, thermoelectric power and de Haas-van Alphen effect were investigated. Antiferromagnetic transition due to divalent Eu atoms were observed at 16.5 K. A charge density wave transition was also found under high pressure accompanied by a Fermi surface reconstruction. These observations were fully accounted for by the Fermi surface topology and corresponding band calculations.
広瀬 雄介*; 吉内 伸吾*; 西村 尚人*; 阪口 準也*; 榎 健太郎*; 岩川 健*; 三浦 泰直*; 杉山 清寛*; 大貫 惇睦; 摂待 力生*; et al.
Journal of the Korean Physical Society, 62(12), p.1858 - 1861, 2013/06
被引用回数：0 パーセンタイル：0(Physics, Multidisciplinary)We succeeded in growing single crystals of YbTIn
(T: Co, Rh, Ir), YbGa, YbTZn (T: Co, Rh, Ir), etc. The electronic and magnetic properties are clarified by measuring the electrical resistivity, magnetic susceptibility, magnetization, specific heat and de Haas-van Alphen effect.
and reference compound ThCd; Studied by the de Haas-van Alphen effect広瀬 雄介*; 三浦 泰直*; 堤 泰樹*; 吉内 伸吾*; 大家 政洋*; 杉山 清寛*; 竹内 徹也*; 山上 浩志*; 山本 悦嗣; 芳賀 芳範; et al.
Physica Status Solidi (B), 250(3), p.642 - 645, 2013/03
被引用回数：4 パーセンタイル：20.45(Physics, Condensed Matter)Electronic states of an antiferromagnet UCd and its reference compound ThCd were investigated by means of de Haas-van Alphen (dHvA) effect. From the cyclotron effective mass determined from the dHvA oscillation, the electronic specific heat of UCd was estimated as 100 mJ/Kmol, much smaller than 840 in the previous report. The result suggests that magnetic excitation contributes significantly to the specific heat.
広瀬 雄介*; 岸野 利彦*; 阪口 準也*; 三浦 泰直*; 本多 史憲*; 竹内 徹也*; 山本 悦嗣; 芳賀 芳範; 播磨 尚朝*; 摂待 力生*; et al.
Journal of the Physical Society of Japan, 81(11), p.113703_1 - 113703_4, 2012/11
被引用回数：24 パーセンタイル：74.26(Physics, Multidisciplinary)Fermi surface and superconducting properties were investigated on an non-centrosymmetric LaNiC compound. Reflecting the crystal structure characteristics, the Fermi surfaces are split due to the antisymmetric spin-orbit interaction. On the other hand, thermodynamic property in the superconducting state follow the conventional BCS theory despite the splitting of Fermi surfaces.
(R: rare earth)森 晶宣*; 太田 尚志*; 吉内 伸吾*; 岩川 健*; 田賀 悠記*; 広瀬 雄介*; 竹内 徹也*; 山本 悦嗣; 芳賀 芳範; 本多 史憲*; et al.
Journal of the Physical Society of Japan, 81(2), p.024720_1 - 024720_10, 2012/02
被引用回数：42 パーセンタイル：83.97(Physics, Multidisciplinary)Single crystals of quasicrystal approximants RCd (R: rare earths) were prepared using the self-flux method and subsequent annealing. A structural transition was confirmed in some of these crystals. Antiferromagnetic ordering was observed for R = Nd, Sm, Tb and Dy. It was found that the structural order-disorder transition has a great influence on the magnetic ordering and transport properties.
Si and YbTZn (T: Co, Rh, Ir)大貫 惇睦; 安井 慎一*; 松下 昌輝*; 吉内 伸吾*; 大家 政洋*; 広瀬 雄介*; Dung, N. D.*; 本多 史憲*; 竹内 徹也*; 摂待 力生*; et al.
Journal of the Physical Society of Japan, 80(Suppl.A), p.SA003_1 - SA003_6, 2011/12
We studied the Fermi surface properties of YbCuSi and YbCuGe with the tetragonal structure by measuring the de Haas-van Alphen (dHvA) oscillations, together with the energy band calculations. It was clarified that 4f electrons contribute to the Fermi surface of a valence fluctuating compound YbCuSi, but not to that of a divalent compound YbCuGe. We also studied the heavy fermion properties of YbTZn (T: Co, Rh, Ir) with the cubic caged structure. The metamagnetic behavior or an abrupt nonlinear increase of magnetization was observed. By measuring the electrical resistivity under pressure and magnetic field, we clarified that the electronic state close to the quantum critical point is realized in YbIrZn at 5.2 GPa and also YbCoZn at ambient pressure.
-US杉山 清寛*; 広瀬 雄介*; 榎 健太郎*; 池田 修悟*; 山本 悦嗣; 立岩 尚之; 芳賀 芳範; 木田 孝則*; 萩原 政幸*; 金道 浩一*; et al.
Journal of the Physical Society of Japan, 80(Suppl.A), p.SA104_1 - SA104_3, 2011/07
被引用回数：3 パーセンタイル：27.45(Physics, Multidisciplinary)Magnetic and transport properties under high magnetic field were studied on a magnetic semiconductor -US. Large magnetization reaching 1.75 
has been observed at 50 T. At the same time, resistivity decreases drastically from insulating behavior at 0 T to almost metallic characteristics at 50 T. The results are discussed based on the magnetic polaron mechanism.
Zn大貫 惇睦; 安井 慎一*; 吉内 伸吾*; 大家 政洋*; 松下 昌輝*; 広瀬 雄介*; 竹内 徹也*; 本多 史憲*; 摂待 力生*; 杉山 清寛*; et al.
Journal of Physics; Conference Series, 273, p.012013_1 - 012013_4, 2011/02
被引用回数：1 パーセンタイル：33.8(Physics, Condensed Matter)Metamagnetic behavior of the heavy fermion compound YbIrZn has been studied experimentally. The metamagnetic transition was clearly seen in the bulk magnetization curve. Near the metamagnetic critical field H
100 kOe, the effective mass of conduction electrons exhibits a significant enhancements. It is suggested that the present metamagnetism is related to the magnetic instability around the quantum critical point.
and CePtSi広瀬 雄介*; 西村 尚人*; 本多 史憲*; 杉山 清寛*; 萩原 政幸*; 金道 浩一*; 竹内 徹也*; 山本 悦嗣; 芳賀 芳範; 松浦 直人*; et al.
Journal of the Physical Society of Japan, 80(2), p.024711_1 - 024711_12, 2011/02
被引用回数：7 パーセンタイル：47.2(Physics, Multidisciplinary)Magnetic and superconducting properties of CeRhGe and CePtSI have been investigated by bulk property measurements and neutron scattering experiments. CeRhGe was found to order antiferromagnetically with an ordered moment 1.3 /Ce along the 
-axis of the orthorhombic unit cell. High pressure resistivity measurements revealed a suppression of the antiferromagnetic transition with increasing pressure and the occurrence of superconductivity near the critical pressure where antiferromagnetism vanishes. Quantum-critical characteristics are expected to these compounds.
Zn竹内 徹也*; 安井 慎一*; 戸田 雅敏*; 松下 昌輝*; 吉内 伸吾*; 大家 政洋*; 片山 敬亮*; 広瀬 雄介*; 吉谷 尚久*; 本多 史憲*; et al.
Journal of the Physical Society of Japan, 79(6), p.064609_1 - 064609_15, 2010/06
被引用回数：42 パーセンタイル：83.65(Physics, Multidisciplinary)Metamagnetic behavior of the heavy-fermion compound YbIrZn was studied by magnetization, de Haas-van Alphen effect, magnetoresistance, specific heat, thermal expansion and magnetostriction. Metamagnetic behavior was observed for all the physical properties at low temperatures. It is remarkable that the Fermi surfaces observed in the dHvA effect unchanges across the metamagnetic transition.
Zn吉内 伸吾*; 戸田 雅敏*; 松下 昌輝*; 安井 慎一*; 広瀬 雄介*; 大家 政洋*; 片山 敬亮*; 本多 史憲*; 杉山 清寛*; 萩原 政幸*; et al.
Journal of the Physical Society of Japan, 78(12), p.123711_1 - 123711_4, 2009/12
被引用回数：40 パーセンタイル：82.7(Physics, Multidisciplinary)High-field magnetization and de Haas-van Alphen effect were measured on a heavy fermion compound YbIrZn. Large cyclotron masses ranging from 4 to 27 
were detected in the dHvA experiment, and are found to be reduced at magnetic fields higher than 120 kOe. From the present experimental results together with the 4f-itinerant band calculations, the 4f electrons are considered to form heavy fermion state.
の磁性山本 悦嗣; 広瀬 雄介*; 榎 健太郎*; 三田村 勝哉*; 杉山 清寛*; 竹内 徹也*; 萩原 政幸*; 金道 浩一*; 芳賀 芳範; 摂待 力生*; et al.
no journal, ,
UCdは格子定数a=9.29
のBaHg型立方晶をとり、その最近接U-U間距離は6.56と大きい。また、UCdは
=5Kとこの系の化合物では転移温度が高く、また常磁性領域における電子比熱係数は840mJ/K
molと大きい。これまでに単結晶による物性測定が行われ、
//
100
方向の磁気相図が得られている。今回新たに、UCdの//100, 110, 111の1.3Kにおける強磁場磁化曲線を測定し、転移磁場及び磁場誘起強磁性相における磁気異方性を見いだした。
Znで実現する新奇な磁場誘起秩序金子 耕士; Raymond, S.*; Ressouche, E.*; Lapertot, G.*; 竹内 徹也*; 広瀬 雄介*; 本多 史憲*; 大貫 惇睦
no journal, ,
同一結晶構造のもとで現れる多様な物性は、系統的な理解を可能にする、魅力的な研究対象である。スクッテルダイトに続き、新たに1-2-20で表される立方晶
において、超伝導や軌道秩序など多彩な物性の発現が明らかとなる中、Ybで構成される6つの化合物Yb
Zn (
: Fe, Co, Ru, Rh, Os, Ir)は、全て重い電子状態を示す。中でもYbCoZnは、電子比熱係数が8J/mol Kを超える、極めて重い電子状態を基底に持つことから、常圧で既に臨界点近傍に位置していると考えられる。実際、加圧により反強磁性秩序が現れる他、磁場では約0.6Tの弱磁場でのメタ磁性転移や、急激な有効質量の減少に加え、
方向に印加した場合にのみ、新たな秩序状態の実現が見出された。今回、大型単結晶を用いた磁場中中性子回折実験により、圧力誘起相の秩序波数とは異なる位置に、特徴的な磁気応答が現れることを見出した。本発表では、観測されたパターンと共に、考えられる磁場誘起秩序相の秩序変数について報告する。
Znで実現する新奇な磁場誘起秩序金子 耕士; Raymond, S.*; Ressouche, E.*; 椎名 亮輔*; 竹内 徹也*; 広瀬 雄介*; 本多 史憲*; 大貫 惇睦; Lapertot, G.*
no journal, ,
同一結晶構造のもとで現れる多様な物性は、系統的な理解を可能にする、魅力的な研究対象である。スクッテルダイトに続き、新たに1-2-20で表される立方晶において、超伝導や軌道秩序など多彩な物性の発現が明らかとなる中、Ybで構成される6つの化合物YbZn (: Fe, Co, Ru, Rh, Os, Ir)は、全て重い電子状態を示す。中でもYbCoZnは、電子比熱係数が8J/mol Kを超える、極めて重い電子状態を基底に持つことから、常圧で既に臨界点近傍に位置していると考えられる。実際、加圧により反強磁性秩序が現れる他、磁場では約0.6Tの弱磁場でのメタ磁性転移や、急激な有効質量の減少に加え、方向に印加した場合にのみ、新たな秩序状態の実現が見出された。今回、大型単結晶を用いた磁場中中性子回折実験により、圧力誘起相の秩序波数とは異なる位置に、特徴的な磁気応答が現れることを見出した。本発表では、観測されたパターンと共に、考えられる磁場誘起秩序相の秩序変数について報告する。
