Faculty Profiles - SETTAI Rikio

Papers - SETTAI Rikio

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17aPS-9 In-NQR study of the magnetic structure in single crystals of CeRhIn_5

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

Meeting Abstracts of the Physical Society of Japan 70 1807 - 1807 2015

17aPS-19 Metamagnesim in CeRh_2Si_2 under High-Pressure using Pulsed High Magnetic Field

Settai R., Kurahasi S., Knafo W., Braithwaite D., Aoki D., Flouquet J.

Meeting Abstracts of the Physical Society of Japan 70 1815 - 1815 2015

18pDA-12 Single crystal growth and electronic state of UPd_2Cd_<20>

Doto H., Hirose Y., Honda F., Li D. X., Homma Y., Aoki D., Settai R.

Meeting Abstracts of the Physical Society of Japan 70 2034 - 2034 2015

Fermi surface, magnetic, and superconducting properties in actinide compounds Reviewed

Yoshichika Onuki, Rikio Settai, Yoshinori Haga, Yo Machida, Koichi Izawa, Fuminori Honda, Dai Aoki

COMPTES RENDUS PHYSIQUE 15 ( 7 ) 616 - 629 2014.8

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER

The de Haas-van Alphen effect, which is a powerful method to explore Fermi surface properties, has been observed in cerium, uranium, and nowadays even in neptunium and plutonium compounds. Here, we present the results of several studies concerning the Fermi surface properties of the heavy fermion superconductors UPt3 and NpPd5Al2, and of the ferromagnetic pressure-induced superconductor UGe2, together with those of some related compounds for which fascinating anisotropic superconductivity, magnetism, and heavy fermion behavior has been observed. (C) 2014 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.

DOI： 10.1016/j.crhy.2014.06.005

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Superconducting Characters under Pressure in Heavy Fermion Compounds CeIr(In1−xCdx)5 Studied by In-NQR Reviewed

Mitsuharu Yashima, Naoki Tagami, Tatsuya Unemori, Katsuyoshi Uematsu, Hidekazu Mukuda, Yoshio Kitaoka, Fuminori Honda, Rikio Settai, Yoshichika Ōnuki

JPS Conference Proceedings, Proceedings of the International Conference on Strongly Correlated Electron Systems (SCES2013) 3 011094-1 - 011094-6 2014.6

Drastic Change of Electronic Properties in Ce2MgSi2 and CeNiIn4 under High Pressure Reviewed

Fuminori Honda, Naohisa Yoshitani, Yusuke Hirose, Kazuhiro Ishida, Takashi Maeta, Atsushi Miyake, Shigeki Tanaka, Katsuya Shimizu, Tetsuya Takeuchi, Kazuyuki Matsubayashi, Yoshiya Uwatoko, Rikio Settai, Dai Aoki, Yoshichika Onuki

JPS Conference Proceedings, Proceedings of the International Conference on Strongly Correlated Electron Systems (SCES2013) 3 011082-1 - 011082-6 2014.6

Precise Thermal Expansion Measurements on Heavy Fermion Compounds YbT2Zn20 (T: Co, Rh, Ir) Reviewed

Tetsuya Takeuchi, Shingo Yoshiuchi, Yusuke Hirose, Fuminori Honda, Rikio Settai, Yoshichika Onuki

JPS Conference Proceedings, Proceedings of the International Conference on Strongly Correlated Electron Systems (SCES2013) 3 011017-1 - 011017-6 2014.6

Novel Electronic States of Heavy Fermion Compound YbCo2Zn20 Reviewed

Fuminori Honda, Yuki Taga, Yusuke Hirose, Shingo Yoshiuchi, Yoshiharu Tomooka, Masahiro Ohya, Jyunya Sakaguchi, Tetsuya Takeuchi, Rikio Settai, Yasuyuki Shimura, Toshiro Sakakibara, Ilya Sheikin, Toshiki Tanaka, Yasunori Kubo, Yoshichika Onuki

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 83 ( 4 ) 2014.4

Language：English Publishing type：Research paper (scientific journal) Publisher：PHYSICAL SOC JAPAN

We studied the heavy fermion compound YbCo2Zn20 with an electronic specific heat coefficient gamma similar or equal to 8000 mJ/(K-2.mol) by measuring the de Haas-van Alphen (dHvA) oscillation, Hall effect, magnetic susceptibility, and magnetization at ambient pressure, as well as the electrical resistivity in magnetic fields of up to 320 kOe and at pressures of up to 5 GPa. The detected Fermi surfaces are small in volume, reflecting the small Brillouin zone based on the large cubic lattice constant a = 14.005 angstrom. The cyclotron effective masses, which were determined from the dHvA experiment, are found to be markedly reduced in magnetic fields. In other words, the detected cyclotron masses of 2.2-8.9 m(0) (m(0): the rest mass of an electron) at H-av = 117 kOe are enhanced to 100-500 m(0) at 0 kOe. By applying pressure, the heavy fermion state disappears at P-c similar or equal to 1.8 GPa and orders antiferromagnetically for P > P-c. The field-induced antiferroquadrupolar phase, which is observed only for H parallel to < 111 > in the magnetic field range from H-Q = 60 kOe to H-Q' = 210 kOe, is found to shift to lower magnetic fields and merge with theantiferromagnetic phase at 4.5 GPa.

DOI： 10.7566/JPSJ.83.044703

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Development of non-metallic diamond anvil cell and quantum oscillation measurement of CePt<inf>2</inf>ln<inf>7</inf> in a pulsed-magnet Reviewed

Atsushi Miyake, Yoshimitsu Kohama, Shunpei Ohta, Yusuke Hirose, Rikio Settai, Kazuyuki Matsubayashi, Yoshiya Uwatoko, Akira Matsuo, Koichi Kindo, Masashi Tokunaga

Journal of Physics: Conference Series 592 ( 1 ) 2014

Publishing type：Research paper (international conference proceedings)

In order to combine the extreme conditions of high pressure and magnetic field, we have developed a non-metallic diamond anvil cell to avoid Joule-heating in a pulsed-magnetic field. Although the cell is deformed with loading, a maximum pressure of ∼ 8.5 GPa can be applied. Quantum oscillation measurements using tunnel diode oscillator have been performed for heavy fermion antiferromagnet CePt2In7 in a pulsed field and at ambient pressure. The detail of the pressure cell and field-induced Fermi surface changes of CePt2In7 are discussed.

DOI： 10.1088/1742-6596/592/1/012149

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Magnetic and fermi surface properties of EuGa<inf>4</inf> Reviewed

Ai Nakamura, Yuichi Hiranaka, Masato Hedo, Takao Nakama, Yasunao Miura, Hiroki Tsutsumi, Akinobu Mori, Kazuhiro Ishida, Katsuya Mitamura, Yusuke Hirose, Kiyohiro Sugiyama, Fuminori Honda, Rikio Settai, Tetsuya Takeuchi, Masayuki Hagiwara, Tatsuma D. Matsuda, Etsuji Yamamoto, Yoshinori Haga, Kazuyuki Matsubayashi, Yoshiya Uwatoko, Hisatomo Harima, Yoshichika Onuki

Journal of the Physical Society of Japan 82 ( 10 ) 2013.10

Publishing type：Research paper (scientific journal)

We grew a high-quality single crystal EuGa4 with the tetragonal structure by the Ga self-flux method, and measured the electrical resistivity, magnetic susceptibility, high-field magnetization, specific heat, thermoelectric power and de Haas-van Alphen (dHvA) effect, together with the electrical resistivity and thermoelectric power under pressure. EuGa4 is found to be a Eu-divalent compound without anisotropy of the magnetic susceptibility in the paramagnetic state and to reveal the same magnetization curve between H ∥ [100] and [001] in the antiferromagnetic state, where the antiferromagnetic easy-axis is oriented along the [100] direction below a Néel temperature TN = 16:5 K. The magnetization curve is discussed on the basis of a simple two-sublattice model. The Fermi surface in the paramagnetic state was clarified from the results of a dHvA experiment for EuGa4 and an energy band calculation for a non-4f reference compound SrGa4, which consists of a small ellipsoidal hole-Fermi surface and a compensated cube-like electron-Fermi surface with vacant space in center. We observed an anomaly in the temperature dependence of the electrical resistivity and thermoelectric power at TCDW = 150K under 2 GPa. This might correspond to an emergence of the charge density wave (CDW). The similar phenomenon was also observed in EuAl4 at ambient pressure. We discussed the CDW phenomenon on the basis of the present peculiar Fermi surfaces. © 2013 The Physical Society of Japan.

DOI： 10.7566/JPSJ.82.104703

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Heavy fermions and unconventional superconductivity in high-quality single crystals of rare-earth and actinide compounds Reviewed

Yoshichika Onuki, Rikio Settai, Kiyohiro Sugiyama, Tetsuya Takeuchi, Fuminori Honda, Yoshinori Haga, Etsuji Yamamoto, Tatsuma D. Matsuda, Naoyuki Tateiwa, Dai Aoki, Ilya Sheikin, Hisatomo Harima

JOURNAL OF THE KOREAN PHYSICAL SOCIETY 63 ( 3 ) 409 - 415 2013.8

Language：English Publishing type：Research paper (scientific journal) Publisher：KOREAN PHYSICAL SOC

The f-electron system in rare-earth and actinide compounds exhibit a variety of characteristic properties including heavy fermions and unconventional superconductivity. The Fermi surface properties in rare-earth and actinide compounds are clarified by the de Haas-van Alphen experiments on the basis of the results of energy band calculations. The effect of pressure on the electronic states of CeRhIn5, CeIrSi3, and YbIr2Zn20 is studied in magnetic fields. An electronic instability, including unconventional superconductivity, occurs at 2.4 GPa in CeRhIn5 and 2.6 GPa in CeIrSi3. An abrupt non-linear increase in the magnetization, namely, a metamagnetic behavior, is found in the heavy fermion compounds, including YbT2Zn20 (T: Co, Rh, Ir). A super-heavy fermion state with a specific heat coefficient of 10 J/(K-2 center dot mol) is realized in YbIr2Zn20 under pressure.

DOI： 10.3938/jkps.63.409

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Metamagnetic Behavior and Effect of Pressure on the Electronic State in Heavy-Fermion Compound YbRh2Zn20 Reviewed

Fuminori Honda, Tetsuya Takeuchi, Shinichi Yasui, Yuki Taga, Shingo Yoshiuchi, Yusuke Hirose, Yoshiharu Tomooka, Kiyohiro Sugiyama, Masayuki Hagiwara, Koichi Kindo, Rikio Settai, Yoshichika Onuki

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 82 ( 8 ) 2013.8

Language：English Publishing type：Research paper (scientific journal) Publisher：PHYSICAL SOC JAPAN

We measured the magnetic susceptibility, high-field magnetization, magnetoresistance, specific heat, and Hall coefficient, together with the electrical resistivity under high pressures and magnetic fields, for the heavy-fermion compound YbRh2Zn20 with the cubic CeCr2Al20-type structure. The metamagnetic behavior was observed at H-m = 65 kOe for the magnetic field along the (100) direction below T-Xmax = 5.3 K, at which the temperature of the magnetic susceptibility indicates a broad maximum. The coefficient A of the T-2 dependence of electrical resistivity rho = rho(0) + AT(2) and the electronic specific heat coefficient C/T possess a broad maximum at H-m. The metamagnetic field H-m is found to decrease with increasing pressure and to become zero at a critical pressure P-c similar or equal to 5.2 GPa. Correspondingly, the A value increases drastically in magnitude, and the Fermi liquid relation is no longer satisfied at 5.2 GPa in zero magnetic field, implying a non-Fermi liquid state. On the other hand, at magnetic fields of H > 20 kOe, the low-temperature resistivity exhibits a T-2 dependence even at 5.2 GPa. The A coefficient decreases rapidly with increasing magnetic field. These results indicate that an electronic state at 5.2 GPa corresponds to the quantum critical point.

DOI： 10.7566/JPSJ.82.084705

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Magnetism and superconductivity in CeCu2Ge2 under high pressures and magnetic fields Reviewed

Fuminori Honda, Takashi Maeta, Yusuke Hirose, Yoshichika Onuki, Atsushi Miyake, Rikio Settai

JOURNAL OF THE KOREAN PHYSICAL SOCIETY 63 ( 3 ) 345 - 348 2013.8

Language：English Publishing type：Research paper (scientific journal) Publisher：KOREAN PHYSICAL SOC

We measured the electrical resistivity of CeCu2Ge2 under various high pressures and strong magnetic fields. Beyond the previous antiferromagnetic critical pressure P (c) similar to 8 GPa, the antiferromagnetic phase is found to exist at much higher pressure of 10.9 GPa even in magnetic fields up to 8 T. The pressure vs. temperature phase diagram and the magnetic field vs. temperature phase diagram under high pressure were constructed. The pressure-induced antiferromagnetic phase is still observed and coexists with pressure-induced superconductivity at 10.9 GPa.

DOI： 10.3938/jkps.63.345

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Single crystal growth and various electronic states in Yb-based compounds Reviewed

Yusuke Hirose, Shingo Yoshiuchi, Naoto Nishimura, Junya Sakaguchi, Kentaro Enoki, Ken Iwakawa, Yasunao Miura, Kiyohiro Sugiyama, Yoshichika Ōnuki, Rikio Settai, Tetsuya Takeuchi, Fuminori Honda, Tatsuma D. Matsuda, Etsuji Ymamoto, Yoshinori Haga, Masayuki Hagiwara

Journal of the Korean Physical Society 62 ( 12 ) 1858 - 1861 2013.7

Publishing type：Research paper (scientific journal)

We succeeded in growing single crystals of YbTIn 5 (T: Co, Rh, Ir), YbGa 4 , YbT 2 Zn 20 (T: Co, Rh, Ir), YbPdGe, Yb 2 Pt 2 Pb, and YbPd 5 Al 2 . The electronic and magnetic properties are clarified by measuring the electrical resistivity, magnetic susceptibility, magnetization, specific heat and de Haas - van Alphen effect. © 2013 The Korean Physical Society.

DOI： 10.3938/jkps.62.1858

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Quadrupole effects in tetragonal crystals PrCu2Si2 and DyCu2Si2 Reviewed

Keisuke Mitsumoto, Saori Goto, Yuichi Nemoto, Mitsuhiro Akatsu, Terutaka Goto, Nguyen D. Dung, Tatsuma D. Matsuda, Yoshinori Haga, Tetsuya Takeuchi, Kiyohiro Sugiyama, Rikio Settai, Yoshichika Onuki

JOURNAL OF PHYSICS-CONDENSED MATTER 25 ( 29 ) 2013.7

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

We have investigated quadrupole effects in tetragonal crystals of PrCu2Si2 and DyCu2Si2 by means of low-temperature ultrasonic measurements. The elastic constant C-44 of PrCu2Si2 exhibits pronounced softening below 70 K down to a Neel temperature T-N = 20 K, which is described in terms of a quadrupole susceptibility for a Gamma(5) doublet ground state and a Gamma(3) singlet first excited state located at 15.6 K in the crystalline electric field scheme. The C-44 and C-66 of DyCu2Si2 also show softening below 70 K down to T-N1 = 9.7 K. A low-lying pseudo-sextet state consisting of three Kramers doublets of Gamma(6) circle plus 2 Gamma(7) brings about softening of C-44 and C-66 in DyCu2Si2.

DOI： 10.1088/0953-8984/25/29/296002

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Effect of pressure on the field-induced ordered phase in the heavy-fermion compound YbCo2Zn20 Reviewed

Tetsuya Takeuchi, Yuki Taga, Shingo Yoshiuchi, Masahiro Ohya, Yusuke Hirose, Fuminori Honda, Rikio Settai, Yoshichika Onuki

JOURNAL OF THE KOREAN PHYSICAL SOCIETY 62 ( 12 ) 1852 - 1854 2013.7

Language：English Publishing type：Research paper (scientific journal) Publisher：KOREAN PHYSICAL SOC

The effect of pressure on the field-induced ordered phase for H aEuro- aOE (c) 111 > in the heavy-fermion compound YbCo2Zn20, which is presumably a field-induced antiferro-quadrupolar (FI-AFQ) phase, was investigated in the pressure range up to 4.5 GPa and under magnetic fields up to 80 kOe. When pressure is applied, the metamagnetic-like transition at H (m) =6 kOe shifts to lower fields and disappears around the quantum critical pressure P (c) similar to 1.8 GPa. A pressure-induced antiferromagnetic (PI-AFM) phase appears at pressures above about 2 GPa, and the critical field H (c) of the PI-AFM phase increases with increasing pressure. On the other hand, the transition field H (Q) of the FI-AFQ phase decreases gradually without showing any anomalous behavior around P (c) and becomes obscure around 4 GPa, where H (c) of the PI-AFM phase and H (Q) of the FI-AFQ phase become comparable. The magnetic field versus pressure, H-P, phase diagram for H aEuro- aOE (c) 111 > at 0.1 K was constructed in the pressure range up to 4.5 GPa.

DOI： 10.3938/jkps.62.1852

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Outbreak of Yersiniosis in Egyptian Rousette Bats (Rousettus aegyptiacus) Caused by Yersinia pseudotuberculosis Serotype 4b Reviewed

S. Nakamura, S. Settai, H. Hayashidani, T. Urabe, S. Namai, Y. Une

JOURNAL OF COMPARATIVE PATHOLOGY 148 ( 4 ) 410 - 413 2013.5

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCI LTD

This report describes an outbreak of yersiniosis in Egyptian rousette bats (Rousettus aegyptiacus) caused by Yersinia pseudotuberculosis serotype 4b. Twelve of 61 bats died between November and December 2008 or in May 2009. The bats often displayed multiple yellow white nodules in the spleen and liver. Microscopically, these consisted of focal necrosis accompanied by inflammatory cell infiltration and colonies of gram-negative bacilli. The bacterial colonies were identified immunohistochemically as T. pseudotuberculosis 04 and T. pseudotuberculosis serotype 4b was identified by bacteriological examination. Polymerase chain reaction demonstrated that the isolate harboured the virulence genes virF,inv and ypmA. YPMa is as a superantigenic toxin that is associated with acute systemic infection in man and may contribute to the virulence of Y. pseudotuberculosis in bats. (C) 2012 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.jcpa.2012.07.007

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Electronic states in antiferromagnet UCd11 and reference compound ThCd11: studied by the de Haasvan Alphen effect Reviewed

Yusuke Hirose, Yasunao Miura, Hiroki Tsutsumi, Shingo Yoshiuchi, Masahiro Ohya, Kiyohiro Sugiyama, Tetsuya Takeuchi, Hiroshi Yamagami, Etsuji Yamamoto, Yoshinori Haga, Rikio Settai, Yoshichika Onuki

PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS 250 ( 3 ) 642 - 645 2013.3

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-V C H VERLAG GMBH

We carried out the de Haasvan Alphen (dHvA) experiment for an antiferromagnet UCd11 and its non-5f reference compound ThCd11 to clarify the Fermi surface properties and the true electronic specific-heat coefficient of UCd11. We observed dHvA signals of both compounds and compared the experimental results with the result of theoretical band calculations. The Fermi surfaces of both compounds are found to be small and closed. The cyclotron masses obtained from the dHvA data of UCd11 are compared with those of reference compounds ThCd11, NpCd11, and LaCd11, and the value of UCd11 is estimated to be about 100mJK2mol1, which is much smaller than the 840mJK2mol1 in the previous reports. It is concluded that this large value is mainly not due to heavy quasiparticles but due to the magnetic contribution to the specific heat.

DOI： 10.1002/pssb.201200765

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Heavy-fermion superconductivity and Fermi-surface properties under pressure Reviewed

Yoshichika Onuki, Rikio Settai, Yasunao Miura, Hiroki Tsutsumi, Fuminori Honda, Hisatomo Harima

PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS 250 ( 3 ) 583 - 588 2013.3

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-V C H VERLAG GMBH

We present an overview of the Fermi-surface properties for antiferromagnets CeRh2Si2, CeIn3, CeRhIn5, and CeIrSi3, which were clarified from the de Haasvan Alphen (dHvA) experiments under strong magnetic fields up to 170kOe and high pressures up to 3GPa. A drastic change of the 4f-electronic state from a 4f-localized Fermi surface to a 4f-itinerant Fermi surface occurs in CeRh2Si2, CeIn3, and CeRhIn5 when the pressure P crosses a critical pressure Pc or P*c. Here, the Neel temperature TN disappears and the superconducting state appears at around Pc or P*c. A critical pressure P*c in CeRhIn5 is the pressure when TN is extrapolated to zero in the temperature vs. pressure phase diagram, and/or the antiferromagnetic state disappears completely even in magnetic fields. This is because the antiferromagnetic state is stable against magnetic fields, or in other words, the antiferromagnetic state recovers in magnetic fields. CeIrSi3 without inversion symmetry in the tetragonal structure is also similar to CeRhIn5 in the superconducting and Fermi-surface properties. It is characteristic that a huge upper critical field at zero temperature in superconductivity Hc2(0)similar or equal to 450 kOe is realized for H parallel to[001] in CeIrSi3 with the superconducting transition temperature Tsc=1.6K.

DOI： 10.1002/pssb.201200913

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Heavy Fermion State in Antiferromagnet UCd11 Reviewed

Etsuji Yamamoto, Yusuke Hirose, Kentaro Enoki, Katsuya Mitamura, Kiyohiro Sugiyama, Tetsuya Takeuchi, Masayuki Hagiwara, Koichi Kindo, Yoshinori Haga, Rikio Settai, Yoshichika Onuki

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 81 2012.12

Language：English Publishing type：Research paper (scientific journal) Publisher：PHYSICAL SOC JAPAN

We grew single crystals of an antiferromagnetic heavy-fermion compound UCd11 and a reference compound ThCd11, and carried out the magnetic susceptibility, high-field magnetization, and specific heat measurements in order to get more insight into the heavy fermion state which is realized in the antiferromagnetic state. The specific heat results suggest that the crystalline electric field (CEF) ground state of UCd11 is a doublet and the total splitting energy of the CEF scheme is less than 100 K. The H - T phase diagram for H parallel to < 100 > is approximately reproduced in the present experiments.

DOI： 10.1143/JPSJS.81SB.SB023

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