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Sakai, Hironori; Kato, Harukazu; Tokunaga, Yo; Kambe, Shinsaku; Walstedt, R. E.; Nakamura, Akio; Tateiwa, Naoyuki*; Kobayashi, Tatsuo*
Journal of Physics; Condensed Matter, 15(28), p.S2035 - S2037, 2003/07
Times Cited Count:3 Percentile:20.85(Physics, Condensed Matter)The cubic-fluorite type uranium dioxide UO is an ionically bounded insulator with localized magnetic moments of U
(5
) ions. Under atmospheric pressure, UO
exhibits a first order antiferromagnetic transition at
=30.8 K accompanied by a small lattice distortion. In order to clarify the interrelation between QQ and exchange interactions in this system, we performed d.c. magnetization measurement under high pressure up to about 1 GPa by a piston-cylinder-type cramped cell. From the d.c. magnetization measurements under high pressure (
0.1 GPa), it is found that UO
shows a weak-ferromagnetic-like transition at
30 K, where the transition temperature is almost independent of external pressure up to 1 GPa. The ferromagnetic component per uranium atom is very small (
), although its component is dependent of pressure. This small ferromagnetic component may come from a canted antiferromagnetic ordering.
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:26.37(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.
Okane, Tetsuo; Fujimori, Shinichi; Mamiya, Kazutoshi; Okamoto, Jun; Muramatsu, Yasuji; Fujimori, Atsushi; Nagamoto, Yasuyuki*; Koyanagi, Tsuyoshi*
Journal of Physics; Condensed Matter, 15(28), p.S2197 - S2200, 2003/07
Times Cited Count:5 Percentile:30.76(Physics, Condensed Matter)The filled skutterudite compounds (
= alkaline earth, rare earth, actinide;
= Fe, Ru, Os;
= pnictogen: P, As, Sb) exhibit a variety of physical properties such as superconductivity, magnetic ordering, heavy-Fermion behavior, and metal-insulator transition. Among them, YbFe
Sb
shows a heavy-Fermion or intermediate-valence behavior in the magnetic, electrical transport, and thermal properties, which might be associated with a valence instability of Yb atom. In this study, the electronic structure of YbFe
Sb
have been investigated by the high-resolution photoemission spectroscopy, using He discharge lamp and synchrotron radiation as an excitation sources. The bulk and surface components of the Yb
signal is clearly divided in the spectra. The relation of the energy position between them is anomalous compared to that of the conventional mixed-valent Yb compounds.
Matsuda, Tatsuma; Ikeda, Shugo; Haga, Yoshinori; Yamamoto, Etsuji; Hedo, Masato*; Uwatoko, Yoshiya*; Onuki, Yoshichika
Journal of Physics; Condensed Matter, 15(28), p.S2019 - S2021, 2003/07
Times Cited Count:1 Percentile:8.29(Physics, Condensed Matter)We have done the pressure experiment of a ferromagnet URhGe with the orthorhombic crystal structure by measuring the electrical resistivity. Two ferromagnetic ordering temperatures
=30 K and
=25 K indicate a different pressure dependence.
is approximately unchanged, 30 K at ambient pressure and 40 K at 6-8 GPa, while
decreases with increasing pressure and most likely becomes zero at 8 GPa. URhGe
is found to be ferromagnetic even at 8 GPa, and then the
and
values of the electrical resistivity
are unchanged against pressure.
Matsuda, Tatsuma; Metoki, Naoto; Haga, Yoshinori; Ikeda, Shugo; Kaneko, Koji; Yamamoto, Etsuji; Onuki, Yoshichika
Journal of Physics; Condensed Matter, 15(28), p.S2023 - S2027, 2003/07
Times Cited Count:6 Percentile:35.03(Physics, Condensed Matter)no abstracts in English
Ikeda, Shugo; Okubo, Tomoyuki*; Inada, Yoshihiko*; Tokiwa, Yoshifumi; Kaneko, Koji; Matsuda, Tatsuma; Yamamoto, Etsuji; Haga, Yoshinori; Onuki, Yoshichika
Journal of Physics; Condensed Matter, 15(28), p.S2015 - S2018, 2003/07
Times Cited Count:6 Percentile:35.03(Physics, Condensed Matter)no abstracts in English
Nakamura, Mitsutaka; Matsuda, Tatsuma; Kakurai, Kazuhisa; Lander, G. H.; Kawarazaki, Shuzo*; Onuki, Yoshichika
Journal of Physics; Condensed Matter, 15(28), p.S1997 - S2000, 2003/07
Times Cited Count:4 Percentile:26.37(Physics, Condensed Matter)The uranium intermetallic compounds UX demonstrate a wide variety of magnetic properties, which depends on the strength of hybridization effect between the 5
-electron state of U atom and the
-,
-,
-electronic states of X atom. However, there are many uncertainties in the origin of these phenomena. UX
systems crystallizes in high symmetric structure, that is cubic AuCu
type. Therefore, the neutron diffraction measurement usually gives no conclusive information on the orientation of the total magnetic moment for UX
compounds because of their multi-domain structures. In this study we have succeeded to induce the anisotropic domain structure by applying the uniaxial pressure and prove the total magnetic moment of UGa
to be along the [011] axis.
Araki, Shingo; Metoki, Naoto; Thamizhavel, A.*; Onuki, Yoshichika
Journal of Physics; Condensed Matter, 15(23), p.S2179 - S2182, 2003/07
no abstracts in English
Metoki, Naoto; Koike, Yoshihiro; Haga, Yoshinori; Kaneko, Koji; Araki, Shingo; McEwen, K. A.*; Kogi, Masafumi*; Aso, Naofumi*; Lander, G. H.; Komatsubara, Takemi*; et al.
Journal of Physics; Condensed Matter, 15(28), p.S1957 - S1963, 2003/07
Times Cited Count:2 Percentile:14.78(Physics, Condensed Matter)no abstracts in English