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Pu
Am
O
uranium-plutonium-americium mixed oxides at 1573, 1773, and 1873 KVauchy, R.; Sunaoshi, Takeo*; Hirooka, Shun; Nakamichi, Shinya; Murakami, Tatsutoshi; Kato, Masato
Journal of Nuclear Materials, 580, p.154416_1 - 154416_11, 2023/07
Times Cited Count：4 Percentile：97.05(Materials Science, Multidisciplinary)
(T=Fe, Rh and Ni)Aoki, Dai*; Homma, Yoshiya*; Shiokawa, Yoshinobu; Sakai, Hironori; Yamamoto, Etsuji; Nakamura, Akio; Haga, Yoshinori; Settai, Rikio*; Onuki, Yoshichika
Journal of the Physical Society of Japan, 74(8), p.2323 - 2331, 2005/08
Times Cited Count：53 Percentile：85.22(Physics, Multidisciplinary)no abstracts in English
(T: Fe, Co, Ni)Honda, Fuminori; Metoki, Naoto; Kaneko, Koji; Aoki, Dai*; Homma, Yoshiya*; Yamamoto, Etsuji; Shiokawa, Yoshinobu; Onuki, Yoshichika; Colineau, E.*; Bernhoeft, N.*; et al.
Physica B; Condensed Matter, 359-361, p.1147 - 1149, 2005/06
Times Cited Count：26 Percentile：69.1(Physics, Condensed Matter)We have succeeded in growing single crystalline samples of NpTGa (T: Fe, Co, Ni). Magnetic structures of these compounds have been studied by neutron diffraction experiment. We summarize the results of the unusual variety of magnetic structure occurred in NpTGa and discuss in terms of electronic structural point of view.
Maebara, Sunao; Goniche, M.*; Kazarian, F.*; Seki, Masami; Ikeda, Yoshitaka; Imai, Tsuyoshi*; Beaumont, B.*
Review of Scientific Instruments, 76(5), p.053501_1 - 053501_7, 2005/05
Times Cited Count：1 Percentile：10.09(Instruments & Instrumentation)Development of a plasma facing module using Cold Isostatic Pressing Graphite (CIPG) had been done for a heat-resistant LHCD antenna. A thin stainless film (10
m), molybdenum film (10m) and copper film (50m) are laid to overlap each other on the CIPG materials, the CIPG surfaces were successfully coated with copper layer by diffusion bonding method. This module has four waveguides and a water cooling channel, the length is 206 mm. High power long pulse operation was successfully achieved up to 250 kW (125 MW/m
)/700s. The module has been successfully tested at a RF power density which is equivalent, in terms of RF electric field (5kV/cm), to the one proposed for the LHCD antenna of ITER-FEAT. The outgassing rate of the copper-coated CIPG is estimated to be 3.2-5.1
10
Pa.m
/s.m at 100
C, it is assessed that a pumping system is not required to evacuate the pressure in the LHCD antenna.
Goniche, M.*; Kazarian, F.*; Bibet, P.*; Maebara, Sunao; Seki, Masami; Ikeda, Yoshitaka; Imai, Tsuyoshi*
Journal of Vacuum Science and Technology A, 23(1), p.55 - 65, 2005/01
Times Cited Count：2 Percentile：9.28(Materials Science, Coatings & Films)Outgassing rates have been measured for long duration (100-4700 seconds) of RF transmission at high power density (50-200 MW/m) for waveguides made of OFHC copper, dispersoid copper, copper-coated carbon fiber composite and copper-coated graphite. The measurements were performed on multi-waveguide(2 to 8)mockups, using a test bed facility equipped with a 3.7 GHz klystron. The effect on the outgassing rate of waveguide surface temperature and of initial wall gas loading('conditioning'), is examined. It is concluded that an outgassing rate of 110
Pams
m
and 510 Pamsm at 300C and 400C respectively, can be expected for the tested material. Based on these measurement results, it is further concluded that no additional pumping will be needed for the LHRF antenna proposed for ITER.
Ga
(=Ni, Pd, Pt)Kaneko, Koji; Metoki, Naoto; Bernhoeft, N.*; Lander, G. H.; Ishii, Yoshinobu; Ikeda, Shugo; Tokiwa, Yoshifumi; Haga, Yoshinori; Onuki, Yoshichika
Physical Review B, 68(21), p.214419_1 - 214419_9, 2003/12
Times Cited Count：59 Percentile：88.71(Materials Science, Multidisciplinary)The crystal structure, lattice strain due to the antiferromagnetic ordering and magnetic form factor in the itinerant 5
compounds UTGa (T: Ni, Pd, Pt) have been studied by neutron scattering. High-resolution powder diffraction revealed that the tetragonality of the U-Ga layers increases with the ionic radius of the transition metal element T. The observed antiferromagnetic reflections can be well explained with the N
el-type structure for UNiGa, whereas UPtGa has the antiferromagnetic stacking of the ferromagnetically ordered uranium moments in the 
-plane. The orbital contributions in the magnetic form factor are reduced from the free ion value, especially for UNiGa. This suppression shows a strong correlation with the bulk magnetic susceptibility. The tetragonality of the U-Ga layers is a sensitive measure of the nearest neighbour interaction, the lattice anomaly, and the orbital contribution and suggests that orbital degrees of freedom may play an important role for the magnetic properties in these itinerant 5 antiferromagnets.
Kato, Harukazu; Sakai, Hironori; Kambe, Shinsaku; Walstedt, R. E.; Tokiwa, Yoshifumi; Onuki, Yoshichika
Acta Physica Polonica B, 34(2), p.1063 - 1066, 2003/09
We performed 
Ga-NMR/NQR studies for UPtGa, which is a 5-itinerant antiferromagnets with Neel temperature 
= 26 K and an electronic specific coefficient 
= 57 mJ/mol K. From the NMR spectrum in the paramagnetic temperature region, the hyperfine coupling constants 
in the paramagnetic state have been evaluated. The magnitude of the transferred field has been evaluated from the zero-applied-field spectrum, yielding a value for the hyperfine coupling constant 
in the antiferromagnetic state. The estimated value of is an order of magnitude larger than that of . This implies the existence of a long-ranged hyperfine interaction path. The mechanism of the hyperfine interaction will be discussed in terms of RKKY interactions.
(T=Ni, Pt)Kato, Harukazu; Sakai, Hironori; Tokunaga, Yo; Tokiwa, Yoshifumi; Ikeda, Shugo; Onuki, Yoshichika; Kambe, Shinsaku; Walstedt, R. E.
Journal of Physics; Condensed Matter, 15(28), p.S2001 - S2005, 2003/07
Times Cited Count：4 Percentile：26.91(Physics, Condensed Matter)UPtGa and UNiGa are 5-itinerant antiferromagnets with N
el temperature = 26 K (Pt), 86 K (Ni). Remarkably, although the two compounds show almost identical Fermi surface properties in the paramagnetic state, recent neutron scattering experiments reveal that UPtGa and UNiGa are quite different in magnetic structure below . In the microscopic viewpoint, we have carried out Ga NMR/NQR measurements for the both coumpounds. We have suceeded in separating the temperature independent term and the Curie-like-temperature-dependent term of the Knight shift 
. This should be a good starting point in considering the magnetism of this system.
itinerant antiferromagnet UPtGa and UNiGaKaneko, Koji; Metoki, Naoto; Lander, G. H.*; Bernhoeft, N.*; Tokiwa, Yoshifumi; Haga, Yoshinori; Onuki, Yoshichika; Ishii, Yoshinobu
Physica B; Condensed Matter, 329-333(1-4), p.510 - 511, 2003/05
Times Cited Count：3 Percentile：21.31(Physics, Condensed Matter)no abstracts in English
(T:Fe, Co and Pt)Ikeda, Shugo; Tokiwa, Yoshifumi*; Okubo, Tomoyuki*; Yamada, Mineko*; Matsuda, Tatsuma; Inada, Yoshihiko*; Settai, Rikio*; Yamamoto, Etsuji; Haga, Yoshinori; Onuki, Yoshichika
Physica B; Condensed Matter, 329-333(2), p.610 - 611, 2003/05
Times Cited Count：13 Percentile：56.02(Physics, Condensed Matter)no abstracts in English
Ikeda, Shugo; Tokiwa, Yoshifumi*; Haga, Yoshinori; Yamamoto, Etsuji; Okubo, Tomoyuki*; Yamada, Mineko*; Nakamura, Noriko*; Sugiyama, Kiyohiro*; Kindo, Koichi*; Inada, Yoshihiko*; et al.
Journal of the Physical Society of Japan, 72(3), p.576 - 581, 2003/03
Times Cited Count：41 Percentile：82.46(Physics, Multidisciplinary)no abstracts in English
Seki, Masami; Ikeda, Yoshitaka; Maebara, Sunao; Moriyama, Shinichi; Naito, Osamu; Anno, Katsuto; Hiranai, Shinichi; Shimono, Mitsugu; Shinozaki, Shinichi; Terakado, Masayuki; et al.
Fusion Science and Technology (JT-60 Special Issue), 42(2-3), p.452 - 466, 2002/09
Times Cited Count：14 Percentile：65.5(Nuclear Science & Technology)no abstracts in English
Kato, Harukazu; Sakai, Hironori; Tokiwa, Yoshifumi; Kambe, Shinsaku; Walstedt, R. E.; Onuki, Yoshichika
Journal of Physics and Chemistry of Solids, 63(6-8), p.1197 - 1200, 2002/06
Times Cited Count：11 Percentile：50.69(Chemistry, Multidisciplinary)no abstracts in English
Tokiwa, Yoshifumi; Ikeda, Shugo*; Haga, Yoshinori; Okubo, Tomoyuki*; Iizuka, Tomoya*; Sugiyama, Kiyohiro*; Nakamura, Akio; Onuki, Yoshichika
Journal of the Physical Society of Japan, 71(3), p.845 - 851, 2002/03
Times Cited Count：40 Percentile：81.12(Physics, Multidisciplinary)We succeeded in growing a high-quality single crystal of an antiferromagnet UPtGa by the self-flux method, and measured the magnetic susceptibility, electrical resistivity, specific heat and de Haas-van Alphen (dHvA) oscillation. We found an antiferromagnetic transition at 26K from the magnetic susceptibility and electrical resistivity measurements. Six dHvA branches were observed, ranging from 1.1410
to 1.1310
Oe. Fermi surfaces consist of two nearly cylindrical and two spherical Fermi surfaces. The cyclotron mass is large, ranging from 10 to 24 
, which is consistent with the electronic specific heat coefficient = 57 mJ/K
mol.
antiferromagnets UNiGa and UPtGaTokiwa, Yoshifumi; Haga, Yoshinori; Metoki, Naoto; Ishii, Yoshinobu; Onuki, Yoshichika
Journal of the Physical Society of Japan, 71(3), p.725 - 728, 2002/03
Times Cited Count：49 Percentile：84.3(Physics, Multidisciplinary)The crystal and magnetic structures of 5 itinerant antiferromagnets UNiGa and UPtGa were studied by means of neutron scattering. The powder diffraction data were well explained by the HoCoGa tetragonal structure with space group P4/mmm. In UNiGa uranium spins in the simple tetragonal lattice has the Nel-type structure with a relatively large moment of 0.9,
/U along the [0,0,1] direction. On the other hand, magnetic moments of uranium atoms in UPtGa are aligned ferromagnetically in the (0,0,1) plane and are directed along the [0,0,1] direction in an antiferromagnetic sequence (
). An ordered moment is 0.24,/U. The nearest-neighbor interaction might be different in these isostructural compounds.
Seki, Masami; Obara, Kenjiro; Maebara, Sunao; Ikeda, Yoshitaka; Imai, Tsuyoshi; Nagashima, Takashi; Goniche, M.*; J.Brossaud*; C.Barral*; G.Berger-By*; et al.
JAERI-Research 96-025, 55 Pages, 1996/06
JAERI-Research-96-025.pdf:2.06MB
no abstracts in English
Maebara, Sunao; Seki, Masami; Suganuma, Kazuaki; Ikeda, Yoshitaka
Fusion Engineering and Design, 30, p.253 - 259, 1995/00
Times Cited Count：2 Percentile：28.04(Nuclear Science & Technology)no abstracts in English
Seki, Masami; Obara, Kenjiro; Maebara, Sunao; Ikeda, Yoshitaka; Imai, Tsuyoshi; Nagashima, Takashi; Goniche, M.*; J.Brossaud*; C.Barral*; G.Berger-By*; et al.
Fusion Engineering and Design, 30, p.357 - 367, 1995/00
Times Cited Count：4 Percentile：49.19(Nuclear Science & Technology)no abstracts in English
*; Shibanuma, Kiyoshi; Okawa, Yoshinao; Seguchi, Tadao
JAERI-M 93-067, 43 Pages, 1993/03
no abstracts in English
Ogiwara, Norio
JAERI-M 91-007, 151 Pages, 1991/02
no abstracts in English
