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MISC - 摂待　力生

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18pPSB-17 CePt_3Siの純良単結晶育成と超伝導(18pPSB 領域8ポスターセッション(f電子系等2:アクチナイド,超伝導,新物質など),領域8(強相関系:高温超伝導,強相関f電子系など))

辻野真彦, 竹内徹也, 摂待力生, 大貫惇睦

日本物理学会講演概要集 62 ( 1 ) 531 - 531 2007年2月

18pWK-9 単結晶CeIrSi_3の圧力誘起超伝導(18pWK Ce化合物の超伝導 I(CeIn_3, CeTX_3等),領域8(強相関系:高温超伝導,強相関f電子系など))

宮内裕一朗, 伊田勇輝, 遠藤豊明, 奥田悠介, 竹内徹也, 摂待力生, 大貫惇睦

日本物理学会講演概要集 62 ( 1 ) 506 - 506 2007年2月

18pPSB-21 CeIrSi_3の高圧比熱 II(18pPSB 領域8ポスターセッション(f電子系等2:アクチナイド,超伝導,新物質など),領域8(強相関系:高温超伝導,強相関f電子系など))

冨岡史明, 梅原出, 小野隆, 辺土正人, 上床美也, 奥田悠介, 摂待力生, 大貫惇睦

日本物理学会講演概要集 62 ( 1 ) 532 - 532 2007年2月

18pWK-12 CePt_3Siの圧力下交流/直流帯磁率測定(18pWK Ce化合物の超伝導 I(CeIn_3, CeTX_3等),領域8(強相関系:高温超伝導,強相関f電子系など))

青木義弘, 住山昭彦, 本山岳, 小田祺景, 安田敬, 摂待力生, 大質惇睦

日本物理学会講演概要集 62 ( 1 ) 506 - 506 2007年2月

Non-fermi liquid behavior in the magnetotransport of CeMln(5) (M : Co and Rh): Striking similarity between quasi two-dimensional heavy fermion and high-T-c cuprates

Y. Nakajima, H. Shishido, H. Nakai, T. Shibauchi, K. Behnia, K. Izawa, M. Hedo, Y. Uwatoko, T. Matsumoto, R. Settai, Y. Onuki, H. Kontani, Y. Matsuda

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 76 ( 2 ) 2007年2月

記述言語：英語出版者・発行元：PHYSICAL SOC JAPAN

We present a systematic study of the dc-resistivity, Hall effect, and magnetoresistance in the normal state of quasi two-dimensional (2D) heavy fermion superconductors CeMIn5 (M: Rh and Co) under pressure. Here the electronic system evolves with pressure from an antiferromagnetic (AF) metal, through a highly unconventional non-Fermi liquid, and finally into a Fermi-liquid state. The novelty of these materials is best highlighted when compared with LaMIn5, a system with similar electronic structures, which shows a nearly temperature independent Hall coefficient and a magnetoresisitance which is well described by the classical Kohler's rule. In sharp contrast, in CeMIn5, the amplitude of the Hall coefficient increases dramatically with decreasing temperature, reaching at low temperatures a value significantly larger than 1/ne, where it is the carrier number. Furthermore, the magnetoresistance is characterized by T- and H-dependence which clearly violate Kohler's rule. We found that the cotangent of the Hall angle Cot Theta(H) varies as T-2, and the magnetoresistance is well scaled by the Hall angle as Delta rho(xx)/rho(xx) alpha tan(2) Theta H. These non-Fermi liquid properties in the electron transport are remarkably pronounced when the AF fluctuations are enhanced in the vicinity of the quantum critical point. We lay particular emphasis on the striking resemblance of these anomalous magnetotransport with those of the high-T-c cuprates. We argue that features commonly observed in quasi 2D heavy fermion and cuprates very likely capture universal features of strongly correlated electron systems in the presence of strong AF fluctuations, holding the promise of bridging our understanding of heavy fermion systems and high-T-c cuprates.

DOI： 10.1143/JPSJ.76.024703

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Single crystal growth and magnetic properties of antiferromagnet Ce2Pd3Si5

Nguyen Duc Dung, Yoshinori Haga, Tatsuma D. Matsuda, Tsutomu Yamada, Arumugam Thamizhavel, Yusuke Okuda, Tetsuya Takeuchi, Kiyohiro Sugiyama, Masayuki Hagiwara, Koichi Kindo, Rikio Settai, Yoshichika Onuki

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 76 ( 2 ) 2007年2月

記述言語：英語出版者・発行元：PHYSICAL SOC JAPAN

We succeeded in growing 4 single crystal Of Ce2Pd3Si5 with the orthorhombic crystal structure by the Sn-flux method and measured the electrical resistivity, specific heat, magnetic susceptibility and magnetization. The antiferromagnetic ordering was confirmed to occure below T-N = 7.2 K. The electronic specific heat coefficient was determined as 77 mJ/(K(2.)mol-Ce). The antiferromagnetic easy-axis was found to be the [001] direction, with an ordered moment of mu(s) = 1.3 mu(B)/Ce, while [100] and [010] directions are hard-axes in magnetization. We observed a metamagnetic transition at H-c = 5.7T for H parallel to [00 1] and a saturation of magnetization above H-s = 12.1 T. The characteristic magnetic phase diagram was constructed. The crystalline electric field (CEF) scheme was also proposed for Ce2Pd3Si5, where the splitting energies between the ground state and two excited doublets in the CEF scheme are estimated to be 87 and 504K, respectively.

DOI： 10.1143/JPSJ.76.024702

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Thermodynamic Studies on Non Centrosymmetric Superconductors by AC Calorimetry under High Pressures

Naoyuki Tateiwa, Yoshinori Haga, Tatsuma D. Matsuda, Etsuji Yamamoto, Shugo Ikeda, Tetsuya Takeuchi, Rikio Settai, Yoshichika Onuki

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 76 140 - 143 2007年1月

記述言語：英語出版者・発行元：PHYSICAL SOC JAPAN

We investigated the non centrosymmetric superconductors CePt3Si and UIr by the ac heat capacity measurement under pressures. We determined the pressure phase diagrams of these compounds. In CePt3Si, the Neel temperature T-N = 2.2 K decreases with increasing pressure and becomes zero at the critical pressure P-AF similar or equal to 0.6 GPa. On the other hand, the superconducting phase exists in a wider pressure region from ambient pressure to P-AF similar or equal to 1.5 GPa. The phase diagram of CePt3Si is very unique and has never been reported before for other heavy fermion superconductors. In UIr, the heat capacity shows an anomaly at the Curie temperature T-C1 = 46 K at ambient pressure, and the heat capacity anomaly shifts to lower temperatures with increasing pressure. The present pressure dependence of TC1 was consistent with the previous studies by the resistivity and magnetization measurements. Previous ac magnetic susceptibility and resistivity measurements suggested the existence of three ferromagnetic phases, FM1-3. C-ac shows a bending structure at 1.98, 2.21, and 2.40 GPa. The temperatures where these anomalies are observed are close to the phase boundary of the FM3 phase.

DOI： 10.1143/JPSJS.76SA.140

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Pressure Effect of Electronic States in Antiferromagnets CeTX3 (T: Transition metal, X: Si and Ge)

Tomoya Kawai, Miho Nakashima, Yusuke Okuda, Hiroaki Shishido, Tetsuya Shimoda, Tatsuma D. Matsuda, Yoshinori Haga, Tetsuya Takeuchi, Masato Hedo, Yoshiya Uwatoko, Rikio Settai, Yoshichika Onuki

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 76 166 - 167 2007年1月

記述言語：英語出版者・発行元：PHYSICAL SOC JAPAN

The effect of pressure on the electronic states in antiferromagnets CeRhSi3, CeIrSi3, CePtSi3, CeRhGe3, CeIrGe3, and CeCoGe3 were studied under pressures up to 8 GPa. Superconductivity was found in CeRhSi3, CeIrSi3, and CeCoGe3 at a critical pressure where the corresponding Neel temperature becomes zero.

DOI： 10.1143/JPSJS.76SA.166

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Specific heat and de Haas-van Alphen experiments on the heavy-fermion superconductor CePt3Si

Tetsuya Takeuchi, Takashi Yasuda, Masahiko Tsujino, Hiroaki Shishido, Rikio Settai, Hisatomo Harima, Yoshichika Onuki

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 76 ( 1 ) 2007年1月

記述言語：英語出版者・発行元：PHYSICAL SOC JAPAN

Specific heat and de Haas-van Alphen (dHvA) measurements were performed on a high-quality single crystal of CePt3Si without inversion symmetry in the tetragonal crystal structure. We observed distinct peaks in the specific heat C at the superconducting transition temperature T-c = 0.46 K and the antiferromagnetic ordering temperature T-N = 2.25 K, compared to the previous data, indicating an improvement of the sample quality. The temperature dependence of the electronic specific heat coefficient C-e/T below about 0.3 K is well described by the equation of C-e/T = gamma(s) + beta T-s with gamma(s) = 34.1 mJ/(K(2.)mol) and beta(s) = 1290mJ/(K(3.)mol), evidencing the existence of line nodes in the superconducting energy gap. Furthermore, the electronic specific heat coefficient y., in the superconducting state indicates a nonlinear magnetic field dependence gamma(s)(H) alpha root H, which also supports the presence of line nodes. We did not observe a discontinuous change of the Fermi surface at P-AF = 0.6 GPa where the Neel temperature becomes zero, but observed a new dHvA branch above 1.5 GPa of which the cyclotron effective mass decreased steeply as a function of pressure from 19m(0) at 2.0 GPa to 11 m(0) at 2.7 GPa.

DOI： 10.1143/JPSJ.76.014702

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Magnetic and electrical properties in CePtSi3 without inversion symmetry in the crystal structure

Tomoya Kawai, Yusuke Okuda, Hiroaki Shishido, Arumugam Thamizhavel, Tatsuma D. Matsuda, Yoshinori Haga, Miho Nakashima, Tetsuya Takeuchi, Masato Hedo, Yoshiya Uwatoko, Rikio Settai, Yoshichika Onuki

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 76 ( 1 ) 2007年1月

記述言語：英語出版者・発行元：PHYSICAL SOC JAPAN

We succeeded in growing a single crystal of CePtSi3 with the tetragonal BaNiSn3-type crystal structure by the Sn-flux method. CePtSi3 is found to be an antiferromagnet with successive two transitions at T-N1 = 4.8 K and T-N2 = 2.4 K. The magnetization for H 11 [100] indicates two metamagnetic transitions at H-c1 = 1.8 kOe and H-c2 = 15 kOe and saturates above H-s = 45 kOe, with an ordered moment of 1.15 mu(B)/Ce. The [100] direction is an easy-axis in magnetization, while the [001] direction corresponds to a hard-axis. The anisotropy of the magnetic susceptibility and magnetization is very similar to that of pressure-induced superconductors of CeRhSi3 and CeIrSi3, which is commonly ascribed to the crystalline electric field effect.

DOI： 10.1143/JPSJ.76.014710

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21pPSA-94 角度分解共鳴光電子分光によるCeIrSi_3の電子構造の研究(領域8ポスターセッション(f電子系等I),領域8,強相関係:高温超伝導,強相関f電子系など)

利光孝文, 宮内裕一朗, 奥田悠介, 摂待力生, 大貫惇睦, 大河内拓雄, 保井晃, 小林正起, 竹田幸治, 岡根哲夫, 斎藤祐児, 藤森淳, 山上浩志

日本物理学会講演概要集 62 ( 0 ) 570 - 570 2007年

18pPSB-5 UIrの電気抵抗率の圧力依存性(18pPSB 領域8ポスターセッション(f電子系等2:アクチナイド,超伝導,新物質など),領域8(強相関系:高温超伝導,強相関f電子系など))

赤澤輝彦, 大貫惇睦, 日高宏之, 小手川恒, 福島賢, 堀彰宏, 小林達生, 山本悦嗣, 芳賀芳範, 摂待力生

日本物理学会講演概要集 62 ( 0 ) 528 - 528 2007年

20pWP-13 CeRh_<1-x>Ir_xIn_5における圧力下超伝導相図(20pWP Ce化合物の超伝導 II,領域8(強相関系:高温超伝導,強相関f電子系など))

和田直希, 小手川恒, 福島賢, 日高宏之, 小林達生, 宍戸寛明, 摂待力生, 大貫惇睦

日本物理学会講演概要集 62 ( 0 ) 634 - 634 2007年

Unconventional Heavy-Fermion Superconductivity of a New Transuranium Compound NpPd5Al2

J. Phys. Soc. Jpn. 76 (2007) 063701(1-4) 76, 063701(1-4) 2007年

High-quality single-crystal growth and unique electronic states in cerium and uranium compounds

Journal of Physics: Condensed Matter, 19, 125203 19, 125203 2007年

Recent Advances in Ce-Based Heavy-Fermion Superconductivity and Fermi Surface Properties

Settai Rikio, Takeuchi Tetsuya, Onuki Yoshichika

Journal of the Physical Society of Japan 76, 051003(1-32) ( 5 ) 51003 - 051003-32 2007年

記述言語：英語出版者・発行元：一般社団法人日本物理学会

We present the recent advances in Ce-based heavy fermion superconductivity. Heavy fermions are formed by the competition between the Ruderman–Kittel–Kasuya–Yosida interaction and the Kondo effect. The application of pressure is useful for controlling the electronic states in antiferromagnets such as CeRh2Si2, Ce2Ni3Ge5, CeIn3, CeRhIn5, and CeIrSi3. For these compounds, the Néel temperature $T_{\text{N } }$ decreases with increasing pressure and reaches zero at the quantum critical pressure $P_{\text{c } }$. Superconductivity appears around $P_{\text{c } }$. In CeRu2, CeCoIn5, and CePt3Si, superconductivity is realized at ambient pressure. For these pressure-induced and ambient-pressure superconductors, we clarified their unconventional characteristics of superconductivity, the close relationship between superconductivity and the dimensionality of the electronic states, and a new aspect of superconductivity in the non-centrosymmetric crystal structure, together with its Fermi surface instability at $P_{\text{c } }$.

DOI： 10.1143/JPSJ.76.051003

CiNii Article

CiNii Books

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Specific Heat Study on the Heavy Fermion Superconductor CePt3Si

Journal of Magnetism and Magnetic Materials, 310, 557-559 310, 557-559 2007年

Crystal growth and magnetic property of a new compound CeAu4Si2

Hiroshi Nakashima, Arumugam Thamizhavel, Tatsuma D. Matsuda, Yoshinori Haga, Tetsuya Takeuchi, Kiyohiro Sugiyama, Rikio Settai, Yoshichika Onuki

Journal of Alloys and Compounds 424 ( 1-2 ) 7 - 12 2006年11月

記述言語：英語

We have succeeded in growing a new ternary Ce compound CeAu4Si2. This compound crystallizes in the tetragonal crystal structure P over(4, ̄) m 2 ({music sharp sign} 1 1 5) with lattice parameters a = 4.3304 Å and c = 27.409 Å. The local environment around Ce atoms is similar to that of the well-known ThCr2 Si2-type tetragonal structure in CeAu2 Si2. Single crystals of CeAu4Si2 were grown by the flux method using an Au4.37 Si eutectic alloy as flux. Electrical resistivity, specific heat and magnetization measurements revealed a ferromagnetic ordering at TC = 5.3 K with a saturation moment of 1.7 μB /Ce. Anisotropic features in the magnetic susceptibility and magnetization were well explained by a crystalline electric field (CEF) model. Estimated excitation energies from the ground state doublet to two excited doublets are 284 and 340 K, respectively. © 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jallcom.2005.12.090

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Magnetic properties and heavy electronic states in the antiferromagnet NpPtGa5

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

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 75 ( 11 ) 2006年11月

記述言語：英語出版者・発行元：PHYSICAL SOC JAPAN

We succeeded in growing a new neptunium compound NpPtGa5 by the Ga-flux method, and measured the electrical resistivity, specific heat, magnetic susceptibility, magnetization and de Haas-van Alphen (dHvA) effect. NpPtGa5 orders antiferromagnetically below T-N=26 K. The magnetic moment is most likely directed along the [100] direction. A cylindrical Fermi surface was detected by the dHvA experiment in the antiferromagnetic state. The cyclotron masses are large, 17-21 m(0), indicating the heavy electronic state in NpPtGa5. The large cyclotron masses are consistent with the large electronic specific heat coefficient, gamma=123 mJ/(K-2 center dot mol), which is the largest among NpTGa5 (T=Fe, Co, Rh, Ni, and Pt).

DOI： 10.1143/JPSJ.75.114715

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23pPSA-43 Ce_2Ni_3Ge_5の磁気構造の研究(23pPSA 領域8ポスターセッション(f電子系等1),領域8(強相関系:高温超伝導,強相関f電子系など))

本多史憲, 目時直人, 松田達磨, 芳賀芳範, Tamizhavel A, 奥田悠介, 摂待力生, 大貫惇睦

日本物理学会講演概要集 61 ( 2 ) 416 - 416 2006年8月

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