研究者詳細 - 摂待　力生

MISC - 摂待　力生

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25aPS-61 RRu_2Zn_<20>(R:希土類)の磁性(領域8ポスターセッション(f電子系等),領域8,強相関系:高温超伝導,強相関f電子系など)

安井慎一, 吉内伸吾, 戸田雅敏, 吉谷尚久, 西村尚人, 太田尚志, 本多史憲, 竹内徹也, 杉山清寛, 摂待力生, 大貫惇睦

日本物理学会講演概要集 64 ( 2 ) 430 - 430 2009年8月

25aPS-45 Ce_2Ir_3Ge_5の量子臨界点近傍における電気抵抗測定II(領域8ポスターセッション(f電子系等),領域8,強相関系:高温超伝導,強相関f電子系など)

中島美帆, 川田達, 天児寧, 村中大志, 石倉達朗, 本多史憲, 松林和幸, 上床美也, 摂待力生, 大貫惇睦

日本物理学会講演概要集 64 ( 2 ) 426 - 426 2009年8月

25aPS-19 CeCoIn5の角度分解磁場中比熱測定による超伝導ギャップ構造の観測(領域8ポスターセッション(f電子系等),領域8,強相関系:高温超伝導,強相関f電子系など)

安幸治, 榊原俊郎, 接待力生, 大貫惇睦, 町田一成

日本物理学会講演概要集 64 ( 2 ) 420 - 420 2009年8月

Superconductivity in a Ternary Silicide Ca2Pt3Si5

Tetsuya Takeuchi, Hiroshi Muranaka, Rikio Settai, Tatsuma D. Matsuda, Etsuji Yamamoto, Yoshinori Haga, Yoshichika Onuki

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 78 ( 8 ) 2009年8月

Observation of Itinerant Ce 4f Electronic States in CeIrSi3 Studied by Angle-Resolved Ce 3d -> 4f Resonance Photoemission Spectroscopy

Takuo Ohkochi, Takafumi Toshimitsu, Hiroshi Yamagami, Shin-ichi Fujimori, Akira Yasui, Yukiharu Takeda, Tetsuo Okane, Yuji Saitoh, Atsushi Fujimori, Yuichiro Miyauchi, Yusuke Okuda, Rikio Settai, Yoshichika Onuki

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 78 ( 8 ) 2009年8月

記述言語：英語出版者・発行元：PHYSICAL SOC JAPAN

We have applied angle-resolved Cc 3d -> 4f resonance photoemission spectroscopy (h nu similar to 882 eV) in the soft X-ray region to the analysis of the non-centrosymmetric pressure-induced superconductor CeIrSi3 and obtained the 4f band structure and Fermi surfaces. We have found that the Ce 4f states are located mainly near the Fermi level and that the photoemission feature corresponding to the dispersive conduction bands across the Fermi level shows considerable resonant enhancement. In addition, the band structure and Fermi surfaces of CeIrSi3 differ from those of the non-f reference compound LaIrSi3, and the differences are well explained by the band structure calculated within local density approximation, in which the Ce 4f states are assumed to be itinerant. These results strongly suggest that the Ce 4f electrons in CeIrSi3 hybridized well with conduction bands and form itinerant electronic states.

DOI： 10.1143/JPSJ.78.084802

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Superconductivity in heavy fermion systems

Y. Onuki, R. Settai, F. Honda, T. Takeuchi, N. Tateiwa, T. D. Matsuda, E. Yamamoto, Y. Haga, H. Harima

PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS 469 ( 15-20 ) 868 - 873 2009年8月

記述言語：英語出版者・発行元：ELSEVIER SCIENCE BV

The heavy fermion state in the f-electron systems is due to competition between the RKKY interaction and the Kondo effect. The typical compound is CeCu(6). TO understand the electronic state, we studied the Fermi surface properties via the de Haas-van Alphen (dHvA) experiment and energy band calculation for CeSn(3,) CeRu(2)Si(2,) UPt(3), and nowadays, transuranium compounds. Pressure is also an important technique to control the electronic state. The Neel temperature T(N) decreases with increasing pressure P and becomes zero at the critical pressure P(c): T(N) -> 0 for P -> Pc. The typical compound is an antiferromagnet CeRhln5, which we Studied from the dHvA experiment under pressure. A change of the 4f-electronic state from localized to itinerant is realized at P(c) similar or equal to 2.4 GPa, revealing the first-order phase transition, together with a divergent tendency of the cyclotron mass at P,. It is stressed that appearance Of Superconductivity in CeRhln(5) is closely related to the heavy fermion state. It is also noted that the parity-mixed novel Superconducting state might be realized in a pressure-induced superconductor CelrSi(3) without inversion symmetry in the crystal structure. (C) 2009 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.physc.2009.05.088

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de Haas-van Alphen Effect and Fermi Surface Properties in High-Quality Single Crystals YbCu2Si2 and YbCu2Ge2

Nguyen Duc Dung, Tatsuma D. Matsuda, Yoshinori Haga, Shugo Ikeda, Etsuji Yamamoto, Tatsuro Ishikura, Toyoaki Endo, Sho Tatsuoka, Yuji Aoki, Hideyuki Sato, Tetsuya Takeuchi, Rikio Settai, Hisatomo Harima, Yoshichika Onuki

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 78 ( 8 ) 2009年8月

記述言語：英語出版者・発行元：PHYSICAL SOC JAPAN

We succeeded in growing high-quality single crystals of a valence fluctuating compound YbCu2Si2 and a divalent compound YbCu2Ge2. The magnetic susceptibility of YbCu2Si2 follows the Curie-Weiss law with Yb3+ at high temperatures, but reveals a broad peak around 40 K for H parallel to [100], which is due to the formation of a 4f-itinerant heavy fermion state at lower temperatures. This is also reflected in the temperature dependence of Hall coefficient, thermoelectric power and thermal expansion. The corresponding de Haas-van Alphen (dHvA) branches are approximately explained by the 4f-itinerant LDA band model, and the 4f-itinerant LDA+U model is found to be much applicable to the dHvA data. The cyclotron effective masses of main Fermi surfaces are relatively large, being 30-40 m(0), which is consistent with the electronic specific heat coefficient gamma = 150 mJ/(K-2.mol). These results indicate that the localized 4f electrons at high temperatures become itinerant at low temperatures, forming a narrow renormalized conduction band. On the other hand, YbCu2Ge2 is a divalent compound, indicating a Pauli paramagnetic susceptibility and a small gamma value of 9-10 mJ/(K-2.mol). The corresponding 4f bands in YbCu2Ge2 are located below the Fermi energy, and do not contribute to the Fermi surfaces. The dHvA data are thus well explained by the Yb2+ band model. These Fermi surfaces in YbCu2Si2 and YbCu2Ge2 are highly different from the Fermi surfaces of a non-4f reference compound YCu2Si2 and a 4f-closed reference compound LuCu2Si2.

DOI： 10.1143/JPSJ.78.084711

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RCu2Si2(R:希土類元素)の純良単結晶育成と4f電子状態の系統的研究

DUNG Nguyen Duc, 大貫惇睦, 武田勇司, 太田有基, 石倉達朗, 杉山清寛, 摂待力生, 松田達磨, 芳賀芳範, 竹内徹也, 播磨尚朝, 後藤沙織, 三本啓輔, 赤津光洋, 根本祐一, 後藤輝孝

固体物理 44 ( 7 ) 433 - 449 2009年7月

High Pressure Phase Diagram of the Non-centrosymmetric Antiferromagnet CeCoGe3

Georg Knebel, Dai Aoki, Gerard Lapertot, Bernard Salce, Jacques Flouquet, Tomoya Kawai, Hiroshi Muranaka, Rikio Settai, Yoshichika Onuki

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 78 ( 7 ) 2009年7月

記述言語：英語出版者・発行元：PHYSICAL SOC JAPAN

We present a detailed study of the high pressure phase diagram of the non-centrosymmetric antiferromagnet CeCoGe3 by measurements of the ac calorimetry in a diamond anvil pressure cell. Under high pressure the magnetic ordering temperature shows a step like decrease due to various successive magnetic phases under high pressure. The magnetic order disappears at a critical pressure of p(c) approximate to 5.5 GPa. Around the critical pressure bulk superconductivity has been detected in the ac calorimetric measurement.

DOI： 10.1143/JPSJ.78.074714

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Strong coupling between antiferromagnetic and superconducting order parameters of CeRhIn5 studied by In-115 nuclear quadrupole resonance spectroscopy

M. Yashima, H. Mukuda, Y. Kitaoka, H. Shishido, R. Settai, Y. Onuki

PHYSICAL REVIEW B 79 ( 21 ) 2009年6月

記述言語：英語出版者・発行元：AMER PHYSICAL SOC

We report on a pressure (P)-induced evolution of magnetism and superconductivity (SC) in a helical magnet CeRhIn5 with an incommensurate wave vector Q(i) = (1/2, 1/2, 0.297) through the In-115 nuclear quadrupole resonance (NQR) measurements under P. Systematic measurements of the In-115-NQR spectrum reveal that the commensurate antiferromagnetism (AFM) with Q(c) = (1/2, 1/2, 1/2) is realized above P-m similar to 1.7 GPa. An important finding is that the size of SC gap and T-c increase as the magnitude of the AFM moment decreases in the P region, where SC uniformly coexists with the commensurate AFM. This result provides evidence of strong coupling between the commensurate AFM order parameter (OP) and SC OP.

DOI： 10.1103/PhysRevB.79.214528

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Two-Dimensional Fermi Surfaces in LaRuPO and LaFePO versus Three-Dimensional Fermi Surfaces in LaFe2P2

Hiroshi Muranaka, Yusuke Doi, Keisuke Katayama, Hitoshi Sugawara, Rikio Settai, Fuminori Honda, Tatsuma D. Matsuda, Yoshinori Haga, Hiroshi Yamagami, Yoshichika Onuki

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 78 ( 5 ) 2009年5月

記述言語：英語出版者・発行元：PHYSICAL SOC JAPAN

We succeeded in observing the de Haas-van Alphen (dHvA) effect in LaRuPO, which is a sister compound of iron-based oxypnictide superconductors. All the detected dHvA frequencies, which correspond to the maximum or minimum cross-sectional areas of Fermi surfaces, approximately follow the 1/cos theta dependence, where theta is a field-tilted angle from the tetragonal [001] direction to the [100] and [110] directions. The Fermi surfaces are found to consist of two cylindrical hole Fermi surfaces and two cylindrical electron Fermi surfaces on the basis of the similar cylindrical Fermi surfaces in LaFePO and the result of energy band calculations. The cyclotron effective mass in LaRuPO is light, ranging from 0.55 to 0.86 m(0), which is compared with a large cyclotron mass in LaFePO. These two-dimensional Fermi surfaces in LaRuPO and LaFePO are also compared with the three-dimensional Fermi surfaces in LaFe2P2.

DOI： 10.1143/JPSJ.78.053705

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Magnetic and Electrical Properties in NpAl4 and UAl4

Dai Aoki, Yoshinori Haga, Yoshiya Homma, Yoshinobu Shiokawa, Etsuji Yamamoto, Akio Nakamura, Rikio Settai, Yoshichika Onuki

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 78 ( 4 ) 2009年4月

記述言語：英語出版者・発行元：PHYSICAL SOC JAPAN

We grew high-quality single crystals of NpAl4. together with UAl4, by the Al-flux method and measured the electrical resistivity. specific heat, magnetic susceptibility, magnetization and de Haas-van Alphen (dHvA) effect. NpAl4 is an antiferromagnet with the Neel temperature T-N = 49 K. The corresponding magnetic moment is most likely directed along the [010] direction in the orthorhornbic crystal structure. The large magnetic entropy at T-N and the Curie-Weiss behavior suggest the localized nature of 5f-electrons with the 5f(4) configuration. The detected dHvA frequencies in NpAl4 are small, indicating that the small magnetic Brillouin zone is formed in the antiferromagnetic state. On the other hand, the large Fermi surfaces are observed in a paramagnet UAl4. The detected cyclotron mass is relatively large, ranging from 3.4 to 23 m(0), which is consistent with the electronic specific heat coefficient gamma = 89 mJ/(K-2.mol).

DOI： 10.1143/JPSJ.78.044712

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28aTA-10 超伝導体NpPd_5Al_2の輸送特性(28aTA f電子系超伝導,領域8(強相関系:高温超伝導,強相関f電子系など))

松田達磨, 芳賀芳範, 青木大, 立岩尚之, 本間佳哉, 池田修悟, 塩川佳伸, 摂待力生, 大貫惇睦

日本物理学会講演概要集 64 ( 1 ) 584 - 584 2009年3月