Faculty Profiles - SETTAI Rikio

Papers - SETTAI Rikio

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Metamagnetism of uranium heavy-fermion compounds UPd2Al3, URu2Si2 and UPt3 Reviewed

K Sugiyama, M Nakashima, M Futoh, H Ohkuni, T Inoue, K Kindo, N Kimura, E Yamamoto, Y Haga, T Honma, R Settai, Y Onuki

PHYSICA B 281 244 - 246 2000.6

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

The high-field magnetization masurements in UPd2Al3, URu2Si2 and UPt3 were carried out up to 55 T at various temperatures. We determined their phase diagrams. The metamagnetic transitions for these compounds were observed up to the characteristic temperatures showing the maxima of the magnetic susceptibilities. (C) 2000 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0921-4526(99)00926-6

Thermal expansion and magnetostriction of UPd3 Reviewed

T Takeuchi, Y Tokiwa, R Settai, Y Haga, E Yamamoto, T Honma, Y Onuki

PHYSICA B 281 602 - 603 2000.6

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

We measured the thermal expansion coefficient and magnetostriction for UPd3 with the hexagonal structure. The temperature dependence of the thermal expansion coefficient was well explained by the crystalline electric field model with the quadrupolar interaction. Three phase transitions at 4.6. 6.8 and 7.8 K were studied precisely by the magnetostriction measurements. (C) 2000 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0921-4526(99)00927-8

Quadrupolar ordering and de Haas-van Alphen effect in UPd3 Reviewed

Y Tokiwa, K Sugiyama, T Takeuchi, R Settai, Y Inada, Y Haga, E Yamamoto, T Honma, K Sakurai, M Nakashima, K Miyake, K Kindo, Y Onuki

PHYSICA B 281 604 - 605 2000.6

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

We determined the magnetic phase diagram of UPd3 with the hexagonal structure. There are three successive phase transitions at 7.5, 6.8 and 4.5 K. This first transition is due to the quadrupolar ordering, which was qualitatively discussed on the basis of the quadrupolar interaction with the order parameter O-zx. The de Haas-van Alphen experiments were also done to clarify the Fermi surface property. (C) 2000 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0921-4526(99)00899-6

Fermi surfaces of RIn3 (R = Tb, Dy, Ho, Er, Tm, Yb and Lu) Reviewed

S Nojiri, Y Katayama, D Aoki, N Suzuki, K Sugiyama, R Settai, Y Inada, Y Onuki, H Harima

PHYSICA B 281 747 - 749 2000.6

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

We observed the de Haas-van Alphen (dHvA) oscillations in RIn3 (R = Tb, Dy, Ho, Er, Tm Yb and Lu). The Fermi surfaces in each RIn3 are compared to the results of FLAPW band calculations. (C) 2000 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0921-4526(99)00902-3

Itinerant f-electron systems of cerium and uranium compounds Reviewed

Y Onuki, Y Inada, H Ohkuni, R Settai, N Kimura, H Aoki, Y Haga, E Yamamoto

PHYSICA B 280 ( 1-4 ) 276 - 280 2000.5

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

The f-electron systems of the cerium and uranium compounds have attracted attention in the context of heavy fermion and anisotropic superconductivity. We clarified an itinerant f-electron nature for UPt3 by the de Haas-van Alphen experiments, detecting heavy conduction electrons with 100m(0). The dHvA oscillation was also observed clearly in both the normal and superconducting mixed states in CeRu2,URu2Si2 and UPd2Al3. An anisotropic energy gap with a line node for URu2Si2 was discussed from the angular dependence of the dHvA amplitude in the mixed state. (C) 2000 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0921-4526(99)01684-1

Fermi surface properties of USi3 Reviewed

Y Tokiwa, H Harima, D Aoki, S Nojiri, M Murakawa, K Miyake, N Watanabe, R Settai, Y Inada, H Sugawara, H Sato, Y Haga, E Yamamoto, Y Onuki

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 69 ( 4 ) 1105 - 1112 2000.4

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

We succeeded in growing a single crystal of USi3 with the cubic crystal structure and measured the transverse magnetoresistance and de Haas-van Alphen(dHvA) oscillation. Fifteen dHvA branches were observed, ranging from 7.37x10(6) to 2.33x10(8) Oe. These branches are in good agreement with theoretical ones based on 5f-itinerant FLAPW band calculations. Cyclotron masses, which are in the range from 0.39 to 4.17 m(0), are approximately the same as the corresponding band masses. These results indicate that the itinerant 5f-electrons form wide bands. The magnetoresistance results confirmed the existence of open orbits, which can he well explained by the band 10-electron Fermi surface.

DOI： 10.1143/JPSJ.69.1105

Cylindrical Fermi surfaces formed by a flat magnetic Brillouin zone in uranium dipnictides Reviewed

D. Aoki, P. Wiśniewski, K. Miyake, N. Watanabe, Y. Inada, R. Settai, E. Yamamoto, Y. Haga, Y. Onuki

Philosophical Magazine B: Physics of Condensed Matter; Statistical Mechanics, Electronic, Optical and Magnetic Properties 80 ( 8 ) 1517 - 1544 2000

Language：English Publishing type：Research paper (scientific journal) Publisher：Taylor and Francis Inc.

We succeeded in growing high-quality single crystals of UX2 (X = Bi, Sb, As or P) by the self-flux and chemical transport methods and carried out de Haas-van Alphen and Shubnikov-de Haas experiments. We found quasi-two-dimensional Fermi surfaces in these U compounds. Fermi surfaces of UBi2 are found to consist of one spherical Fermi surface and two cylindrical Fermi surfaces. Each Fermi surface in UBi2 changes into two cylindrical surfaces in USb2 and UAs2. This change in the Fermi surfaces is well explained on the basis of a flat magnetic Brillouin zone. The quasi-two-dimensional character of the Fermi surfaces is mainly due to the conduction electrons in the U plane, including the 5f electrons. The itinerant nature of 5f electrons is reflected in the large cyclotron masses. The magnetic breakthrough (breakdown) phenomenon is also discussed for USb2.

DOI： 10.1080/13642810008208582

Magnetic phase diagram in UCd11 Reviewed

D Aoki, T Inoue, K Kindo, N Suzuki, K Miyake, Y Inada, R Settai, K Sugiyama, E Yamamoto, Y Haga, Y Onuki

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 68 ( 9 ) 3117 - 3118 1999.9

Fermi surface properties and de Haas-van Alphen oscillation in both the normal and superconducting mixed states of URu2Si2 Reviewed

H Ohkuni, Y Inada, Y Tokiwa, K Sakurai, R Settai, T Honma, Y Haga, E Yamamoto, Y Onuki, H Yamagami, S Takahashi, T Yanagisawa

PHILOSOPHICAL MAGAZINE B-PHYSICS OF CONDENSED MATTER STATISTICAL MECHANICS ELECTRONIC OPTICAL AND MAGNETIC PROPERTIES 79 ( 7 ) 1045 - 1077 1999.7

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

We have succeeded in growing a high-quality single crystal of URu2Si2 with a residual resistivity ratio of 255 and performed magnetoresistance and de Haas-van Alphen (dHvA) experiments. The dHvA oscillations were observed clearly in both the normal and superconducting mixed states. From the magnetoresistance experiments, it is concluded that URu2Si2 is a compensated metal with equal carrier numbers of electrons and holes. In the dHvA experiments we observed three kinds of Fermi surfaces. We studied precisely the Fermi surface properties in both the normal and mixed states. The dHvA frequency does not change in magnitude between the normal and mixed states, while the cyclotron effective mass is reduced, and the corresponding Dingle temperature or scattering rate of the conduction electron increases in the mixed state.

DOI： 10.1080/014186399256916

Crystal growth and cylindrical Fermi surfaces of USb2 Reviewed

D Aoki, P Wisniewski, K Miyake, N Watanabe, Y Inada, R Settai, E Yamamoto, Y Haga, Y Ouki

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 68 ( 7 ) 2182 - 2185 1999.7

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

We have gown high-quality single crystals of tetragonal USb2 using a flux method. We have detected five branches in de Haas-van Alphen (dHvA) experiments. Frequencies of all dHvA branches follow the 1/cos theta-dependence, revealing the presence of cylindrical Fermi surfaces, where theta is a tilt angle from [001] to [100]. The cyclotron masses are in the range from 1.84 to 8.33 m(0). The two-dimensional Fermi surfaces are due to the conduction electrons in the U-plane, including the itinerant 5f-electrons.

DOI： 10.1143/JPSJ.68.2182

Electrical and thermal properties of UB2 Reviewed

E Yamamoto, T Honma, Y Haga, Y Inada, D Aoki, N Suzuki, R Settai, H Sugawara, H Sato, Y Onuki

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 68 ( 3 ) 972 - 975 1999.3

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

We have measured the electrical resistivity, thermoelectric power, magnetic susceptibility, magnetoresistance and specific heat of a Pauli paramagnetic compound UB2. The magnetoresistance shows an extremely large H-2-dependence for any field directions, indicating a compensated metal without an open orbit. This result is consistent with the results of the dHvA experiment and 5f-itinerant hand calculation.

DOI： 10.1143/JPSJ.68.972

Pressure Effect on the Fermi Surface Properties of the Heavy Fermion Compound CeRu<SUB>2</SUB>Si<SUB>2</SUB>

H.Aoki, M.Takashita, N.Kimura, C.Terakura, T.Terashima, S.Uji, T.Matsumoto, K.Maezawa, R.Settai, Y.Onuki

Proceedings of 4<SUP>th</SUP> Int. Symposium on Advanced Physical Fields 37 - 40 1999.3

Critical behavior of susceptibility at the nuclear ordering transition in PrCu6 Reviewed

K Akashi, K Kawabata, A Matsubara, O Ishikawa, T Hata, H Ishii, T Kodama, A Koyanagi, R Settai, Y Onuki

PHYSICAL REVIEW LETTERS 82 ( 6 ) 1297 - 1300 1999.2

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

The nuclear susceptibility and magnetization of a Van Vleck paramagnet PrCu6 have been measured through the nuclear ordering transition. At zero magnetic field, the susceptibility shows a critical behavior at the transition temperature of 2 mK. This critical behavior shrinks and disappears as the applied magnetic field is increased. It is found that this behavior of the susceptibility is consistent with the electrical resistivity anomaly near the transition in its frequency and magnetic field dependence. The magnetization in magnetic fields shows a ferromagnetic increase at the transition, which coincides with the resistivity decrease in the ordered state. [S0031-9007(98)08321-5].

DOI： 10.1103/PhysRevLett.82.1297

dHvA effect study of the metamagnetic transition in CeRu2Si2 under pressure Reviewed

M Takashita, H Aoki, T Miura, C Terakura, S Uji, T Matsumoto, K Maezawa, R Settai, Y Onuki

PHYSICA B-CONDENSED MATTER 259-61 1093 - 1094 1999.1

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

We have performed the de Haas-van Alphen effect study under high pressure for both the field ranges below and above the metamagnetic transition field (H-m) in CeRu2Si2. The effective masses below H-m decrease considerably with pressure as expected from various macroscopic measurements, whereas above H-m it is found that the effective mass for the large hole surface does not change substantially with pressure. The dHvA oscillations can be traced all the way from below to above H-m and it is found that the transition of the dHvA oscillations takes place in a narrower held range than the transition width of magnetization. (C) 1999 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0921-4526(98)00914-4

de Haas-van Alphen effect in LaNi2Ge2 Reviewed

K Maezawa, S Sakane, T Fukuhara, H Ohkuni, R Settai, Y Onuki

PHYSICA B-CONDENSED MATTER 259-61 1091 - 1092 1999.1

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

The de Haas-van Alphen (dHvA) Effect of LaNi2Ge2, a reference material for a non-magnetic heavy electron compound CeNi2Ge2, has been investigated. Many branches with the frequencies from 26 MG to 120 MG have been observed. The angular dependence of the frequencies indicates a complicated Fermi surface which consists of a multi-connected surface. The cyclotron effective masses for each branch were also determined to be 1.2m(0)-2.7m(0). (C) 1999 Published by Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0921-4526(98)00735-2

Metamagnetic-like anomaly in CeCu6 Reviewed

Y Aoki, T Namiki, TD Matsuda, H Sugawara, H Sato, R Settai, Y Onuki

PHYSICA B-CONDENSED MATTER 259-61 28 - 29 1999.1

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

The field dependences of specific heat C and magnetocaloric effect (MCE) Delta T/Delta B in CeCu6 have been measured to investigate the thermadynamical aspects of the weak metamagnetic-like anomaly (MA). Around 1.7 T both properties exhibit anomalous behaviors, which have close similarities with those in CeRu2Si2. This fact suggests that the quasiparticle density of states in CeCu6 has a faint peak structure near the Fermi level, which is superposed on the Kondo-resonance peak. (C) 1999 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0921-4526(98)01165-X

Metamagnetic transitions based on the quadrupole moment in RCu2 single crystals Reviewed

K Sugiyama, M Nakashima, Y Yoshida, R Settai, T Takeuchi, K Kindo, Y Onuki

PHYSICA B-CONDENSED MATTER 259-61 896 - 897 1999.1

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

We studied the high-field magnetization in RCu2 (R = Ce, Pr, Nd, Sm, Dy, Tb and Ho) with the orthorhombic CeCu2-type crystal structure. The field-induced metamagnetic transition due to the switching of the different magnetic anisotropy states was observed in RCu2 (R = Ce, Pr, Dy and Tb). The origin of the transition is analyzed theoretically on the basis of the quadrupolar interaction and crystalline electric field. (C) 1999 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0921-4526(98)00808-4

Fermi surfaces of RPb3 Reviewed

D Aoki, Y Katayama, S Nojiri, R Settai, Y Inada, K Sugiyama, Y Onuki, H Harima, Z Kletowski

PHYSICA B-CONDENSED MATTER 259-61 1083 - 1084 1999.1

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

We have observed the de Haas-van Alphen (dHvA) oscillations in SmPb3, GdPb3, EuPb3 and YbPb3. Detected dHvA branches are discussed on the basis of the result of the FLAPW band calculation. (C) 1999 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0921-4526(98)00938-7

Antiferroquadrupolar ordering and Fermi surface property in PrPb3 Reviewed

D. Aoki, Y. Katayama, R. Settai, Y. Inada, Y. Onuki, H. Harima, Z. Kletowski, T. Tayama, T. Sakakibara

Phys. of Strongly Correlated Electron Systems eds. T. Komatsubara, H. Fujii, Y. Onuki, H. Shiba, Jpn. J. Appl. Phys. 11 188 1999.1

De Haas-van Alphen effect of UB2, UB4 and UGa3 Reviewed

E. Yamamoto, T. Honma, Y. Haga, D. Aoki, M. Hedo, Y. Inada, R. Settai, H. Yamagami, Y. Onuki

Phys. of Strongly Correlated Electron Systems eds. T. Komatsubara, H. Fujii, Y. Onuki, H. Shiba, Jpn. J. Appl. Phys. 11 209 1999.1

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