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Ikeda, Shugo; Metoki, Naoto; Haga, Yoshinori; Kaneko, Koji; Matsuda, Tatsuma; Onuki, Yoshichika
Physica B; Condensed Matter, 359-361, p.1030 - 1032, 2005/06
Times Cited Count：1 Percentile：6.23(Physics, Condensed Matter)We have succeeded to grow a single crystal of uranium ternary intermetallic compound UPdGa by the Ga self-flux method. The magnetic susceptibility showed a weak temperature dependence and small anisotropy,consistent with an itinerant character of 5
electrons. We observed a clear drop in the susceptibility and electrical resistivity below the Neel temperature 
= 31 K. The magnetic structure was studied by means of a neutron diffraction measurement. We observed an antiferromagnetic peak with the propagation vector 
=[0,0,1/2]. The uranium 5 moment of 0.33
parallel to the 
-axis was found to order ferromagnetically in the basal -plane and coupled antiferromagnetically along the -axis.
SiMetoki, Naoto; Kaneko, Koji; Matsuda, Tatsuma; Galatanu, A.; Takeuchi, Tetsuya*; Hashimoto, Shin*; Ueda, Taiki*; Settai, Rikio*; Onuki, Yoshichika*; Bernhoeft, N.*
Physica B; Condensed Matter, 359-361, p.383 - 385, 2005/06
Times Cited Count：1 Percentile：6.23(Physics, Condensed Matter)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：69.18(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.
Sb
Raymond, S.*; Flouquet, J.*; Kuwahara, Keitaro*; Iwasa, Kazuaki*; Kogi, Masafumi*; Kaneko, Koji; Metoki, Naoto; Sugawara, Hitoshi*; Aoki, Yuji*; Sato, Hideyuki*
Physica B; Condensed Matter, 359-361, p.898 - 900, 2005/06
Times Cited Count：2 Percentile：11.66(Physics, Condensed Matter)The low lying magnetic excitations of the unconventional heavy fermion superconductor PrOsSb were studied by inelastic neutron scattering on single crystalline sample. The crystal field excitation first evidenced at 0.7 meV on powder samples is found to have a minimum of energy at the zone boundary corresponding to the wavevector of antiferro-quadrupolar instability. The evolution of the magnetic excitation spectrum under magnetic field confirms the singlet ground state.
SiMatsuda, Tatsuma; Haga, Yoshinori; Ikeda, Shugo; Galatanu, A.; Onuki, Yoshichika
Physica B; Condensed Matter, 359-361, p.1069 - 1071, 2005/04
Times Cited Count：3 Percentile：17(Physics, Condensed Matter)We have succeeded in growing a high-quality single crystal of UCuSi with the tetragonal structure by the Sn-flux method and measured the magnetic susceptibility and magnetization. UCuSi is confirmed to order antiferromagnetically below 
= 106 K, and follows a successive ferromagnetic ordering at 
= 100 K. The magnetic properties are highly anisotropic, reflecting the crystal structure. An easy-axis of magnetization is found to be the [001] direction (-axis), while the [100] direction (
-axis) corresponds to the hard-axis in magnetization. The saturation moment is determined as 1.8
/U.
-electron systemsHotta, Takashi
Physica B; Condensed Matter, 359-361, p.1003 - 1005, 2005/04
Times Cited Count：1 Percentile：6.23(Physics, Condensed Matter)In order to understand magnetic properties of filled skutterudite materials, we evaluate magnetic susceptibility of the Anderson model with orbital degeneracy by using the numerical renormalization group method. Even when the local ground state is 
, magnetic fluctuations significantly remain, if 
is the excited state with small excitation energy, as experimentally proposed for Pr-based filled skutterudite compounds.
Kuzushita, Kaori; Ishii, Kenji; Owada, Kenji; Murakami, Yoichi; Kaneko, Koji; Metoki, Naoto; Lander, G. H.; Ikeda, Shugo; Haga, Yoshinori; Onuki, Yoshichika
Physica B; Condensed Matter, 359-361, p.1045 - 1047, 2005/04
Times Cited Count：2 Percentile：11.66(Physics, Condensed Matter)In UNiGa which shows antiferromagnetic ordering below 
= 86 K with 0.75 
/U, we observed resonant magnetic reflections using synchrotron X-ray tuned the incident photon energy near M-edge of U and K-edge of Ga, and the large enhancement about 10
at just resonant energy of Ga K-edge although Ga is a nonmagnetic element. It is considered that the origin of the magnetic resonant scattering intensity at Ga K-edge is the Ga-4
orbital polarization induced by the 5
orbital polarization at the neighboring U atom due to the hybridization.
NiAl
Haga, Yoshinori; Matsuda, Tatsuma; Ikeda, Shugo; Galatanu, A.; Matsumoto, Takuya*; Sugimoto, Toyonari*; Tada, Toshiji*; Noguchi, Satoru*; Onuki, Yoshichika
Physica B; Condensed Matter, 359-361, p.1006 - 1008, 2005/04
Times Cited Count：2 Percentile：11.66(Physics, Condensed Matter)A new ternary uranium-based intermetallic compound UNiAl has been symthesized. It crystallizes in the unique flat orthorhombic structure. Uranium atoms occupy two crystallographic 4 and 8 sites where local chemical environments are quite similar. The temperature dependence of the magnetic susceptibility 
demonstrates peculiar magnetic anisotropy; along 
- and -axes obeys the Curie-Weiss law above 23 K, while along -axis is small and temperature independent. At 23 K, only 
shows a sharp cusp corresponding to the antiferromagnetic ordering, while 
remains paramagnetic behavior down to 2 K. These results and crystallographical considerations lead to a conclusion that only uranium atoms at the 8 site order antiferromagnetically at = 23 K, while uranium atoms at the 
site do not order down to 50 mK.
Nakamura, Akio; Akabori, Mitsuo; Ogawa, Toru; Huntelaar, M. E.*
Physica B; Condensed Matter, 359-361, p.1021 - 1023, 2005/04
Times Cited Count：1 Percentile：6.23(Physics, Condensed Matter)no abstracts in English
; 
O-NMR studyTokunaga, Yo; Homma, Yoshiya*; Kambe, Shinsaku; Aoki, Dai*; Sakai, Hironori; Yamamoto, Etsuji; Nakamura, Akio; Shiokawa, Yoshinobu; Walstedt, R. E.; Yasuoka, Hiroshi
Physica B; Condensed Matter, 359-361, p.1096 - 1098, 2005/04
Times Cited Count：7 Percentile：33.79(Physics, Condensed Matter)In order to elucidate the nature of the exotic ordered phase of NpO below 
= 26 K, we have initiated the first O-NMR measurements. From the temperature dependence of the O-NMR spectrum, the occurrence of two inequivalent oxygen sites has been confirmed below . This finding verifies the lowering of symmetry in the ordered state of NpO.
Onishi, Hiroaki; Hotta, Takashi
Physica B; Condensed Matter, 359-361, p.669 - 671, 2005/04
Times Cited Count：3 Percentile：17(Physics, Condensed Matter)By using the density matrix renormalization group method, we investigate ground- and excited-state properties of the 
-orbital degenerate Hubbard model at quarter filling for two kinds of lattices, zigzag chain and ladder. In the zigzag chain, the system is effectively regarded as a decoupled double chain of the 
=1/2 antiferromagnetic Heisenberg model, and the spin gap is approximately zero, similar to the case of weakly coupled Heisenberg chains. On the other hand, in the ladder, the spin correlation on the rung remains robust and the spin gap exists.
Kambe, Shinsaku; Homma, Yoshiya*; Tokunaga, Yo; Sakai, Hironori; Aoki, Dai*; Yamamoto, Etsuji; Nakamura, Akio; Shiokawa, Yoshinobu; Walstedt, R. E.
Physica B; Condensed Matter, 359-361, p.1072 - 1074, 2005/04
Times Cited Count：4 Percentile：21.66(Physics, Condensed Matter)We report a 
Ga NMR study of the antiferromagnet NpFeGa. In the paramagnetic state, hyperfine parameters such as NMR shift, electric field gradient and hyperfine coupling constant have been determined for the two crystallographically inequivalent Ga sites. These parameters are found to have a similar magnitude to those of UNiGa and UPtGa.
(T=Fe, Co, Ni)Yamamoto, Etsuji; Aoki, Dai*; Homma, Yoshiya*; Shiokawa, Yoshinobu; Haga, Yoshinori; Nakamura, Akio; Onuki, Yoshichika
Physica B; Condensed Matter, 359-361, p.1099 - 1101, 2005/04
Times Cited Count：7 Percentile：33.79(Physics, Condensed Matter)We succeeded in growing a high-quality single crystal of NpTGa (T=Fe, Co, Ni) with the tetragonal structure by the Ga-flux method and measured the electrical resistivity, magnetic susceptibility and magnetization. NpFeGa and NpCoGa are antiferromagnets with a N
el temperature of 116 K and 47 K, respectively. On the other hand, NpNiGa orders ferromagnetically below 30 K, but changes into another magnetic state with an antiferromagnetic character at 18 K.
