Kajimoto, Ryoichi; Nakajima, Kenji; Kawamura, Seiko; Inamura, Yasuhiro; Okuda, Tetsuji*; Tomiyasu, Keisuke*
JPS Conference Proceedings (Internet), 3, p.014018_1 - 014018_5, 2014/06
Nakano, Hiroki*; Sakai, Toru
JPS Conference Proceedings (Internet), 3, p.014003_1 - 014003_6, 2014/06
The magnetization processes of the S=1/2 isotropic Heisenberg quantum antiferromagnets on the kagome and triangular lattices are studied. We find that for the kagome-lattice antiferromagnet, the behavior of the derivative around the 1/3 height of the magnetization saturation is quite different from the cases of typical magnetization plateaux. This new phenomenon is called the "magnetization ramp". In order to clarify the difference between the magnetization ramp and the conventional magnetization plateau, we study a generalized anisotropic triangular-lattice model including the regular-triangular- and the kagome-lattice antiferromagnets in the parameter space. It revealed a quantum phase transition between the triangular- and kagome-lattices at 1/3 of the saturation magnetization.
Matsumoto, Yuji; Haga, Yoshinori; Tateiwa, Naoyuki; Yamamoto, Etsuji; Kimura, Noriaki*; Aoki, Haruyoshi*; Fisk, Z.
JPS Conference Proceedings (Internet), 3, p.011097_1 - 011097_5, 2014/06
Kaneko, Koji; Raymond, S.*; Ressouche, E.*; Lapertot, G.*; Takeuchi, Tetsuya*; Hirose, Yusuke*; Honda, Fuminori*; Onuki, Yoshichika
JPS Conference Proceedings (Internet), 3, p.011061_1 - 011061_5, 2014/06
Tsutsui, Kenji; Toyama, Takami*; Maekawa, Sadamichi
JPS Conference Proceedings (Internet), 3, p.017008_1 - 017008_6, 2014/06
Impurity substitution for copper in high-Tc cuprate superconductors has attracted much attention. For Ni substitution, it has been argued from several experiments that hole carriers are strongly localized at around Ni sites. We have demonstrated theoretically that a hole can be bound in the NiO plaquette forming the Zhang-Rice doublet. In this study, we examine the interaction between the Zhang-Rice doublet and hole carriers. We carry out the numerically exact diagonalization on small clusters of the d-p model with a Ni impurity site and calculate the resonant inelastic X-ray scattering spectra for Ni K-edge.
Kodama, Katsuaki; Igawa, Naoki; Shamoto, Shinichi; Ikeda, Kazutaka*; Oshita, Hidetoshi*; Kaneko, Naokatsu*; Otomo, Toshiya*; Suzuya, Kentaro; Hoshikawa, Akinori*; Ishigaki, Toru*
JPS Conference Proceedings (Internet), 3, p.013012_1 - 013012_6, 2014/06
Fujimori, Shinichi; Kawasaki, Ikuto*; Yasui, Akira*; Takeda, Yukiharu; Okane, Tetsuo; Saito, Yuji; Fujimori, Atsushi; Yamagami, Hiroshi; Haga, Yoshinori; Yamamoto, Etsuji; et al.
JPS Conference Proceedings (Internet), 3, p.011072_1 - 011072_5, 2014/06
In this presentation, we review some of our recent photoemission studies on uranium superconductors by means of soft X-ray synchrotron radiation ARPES (SX-ARPES). Results of SX-ARPES study on URhGe and UPdAl will be presented. URhGe is a ferromagnetic superconductor with = 9.5 K and = 0.26 K while UPdAl is an antiferromagnetic superconductor with = 14 K and = 1.8 K. We have revealed the three-dimensional electronic structures of those compounds by SX-ARPES, and they are compared with those calculated by LDA.
Tateiwa, Naoyuki; Haga, Yoshinori; Yamamoto, Etsuji; Fisk, Z.
JPS Conference Proceedings (Internet), 3, p.011086_1 - 011086_7, 2014/06
Paramagnetic -US is a semiconductor with the band gap of 90 K. The applying pressure on -US induces a weak ferromagnetic state above 0.5 GPa and the phase is understood as "induced moment ferromagnetism". In this study, we have measured the magnetization in -US across the insulator-metal transition at 5 GPa with a ceramic anvil high pressure cell. The spontaneous magnetic moment is strongly enhanced at the transition pressure from 0.04 to 0.4 /U. The ferromagnetic state may be stabilized by the larger carrier concentration.
JPS Conference Proceedings (Internet), 3, p.011023_1 - 011023_6, 2014/06
Okane, Tetsuo; Takeda, Yukiharu; Yano, Kazuo*; Fujimori, Atsushi; Yamagami, Hiroshi; Nishimura, Katsuhiko*; Ishikawa, Yoshikazu*; Sato, Kiyoo*
JPS Conference Proceedings (Internet), 3, p.011028_1 - 011028_6, 2014/06
Metoki, Naoto; Sakai, Hironori; Suzuki, Michito; Yamamoto, Etsuji; Haga, Yoshinori; Matsuda, Tatsuma; Ikeda, Shugo*
JPS Conference Proceedings (Internet), 3, p.013011_1 - 013011_6, 2014/06
Uranium chalcogenides are highly interesting because of the variety of the physical properties from 5-based metal and Mott-Hibbard insulator. Especially dichalcogenide family exhibits a metal-insulator crossover depending on the chalcogenide elements, or under magnetic field and pressure. In this talk we present a recent result of our neutron scattering study on uranium dichalcogenide, which demonstrates that the metal-insulator crossover is related to the change of 5 character from localized to itinerant. The electronic structure related to this phenomenon is discussed based on the band calculation.
Yamamoto, Etsuji; Tateiwa, Naoyuki; Haga, Yoshinori; Ikeda, Shugo*; Sakai, Hironori; Onuki, Yoshichika; Fisk, Z.
JPS Conference Proceedings (Internet), 3, p.011095_1 - 011095_4, 2014/06
Nakamura, Hiroki; Machida, Masahiko
JPS Conference Proceedings (Internet), 3, p.017034_1 - 017034_4, 2014/06
We perform hybrid density functional calculations taking account of spin-orbit couplings on plutonium dioxides in order to numerically obtain its observed ground state, i.e., the paramagnetic insulating state and properly calculate the material properties. Generally, it is known for plutonium dioxides that the standard LDA calculations give metallic states. So far, we clarified that inclusion of the spin-orbit coupling in addition to the strong correlation through LDA+U is responsible for the paramagnetic insulating state. In this paper, we show that hybrid density functional calculations with spin-orbit couplings yield the paramagnetic insulating states similar to those obtained by LDA+U.
Nagai, Yuki; Nakamura, Hiroki; Machida, Masahiko
JPS Conference Proceedings (Internet), 3, p.015013_1 - 015013_6, 2014/06
no abstracts in English
Kobayashi, Keita; Okumura, Masahiko; Ota, Yukihiro*; Yamada, Susumu; Machida, Masahiko
JPS Conference Proceedings (Internet), 3, p.016006_1 - 016006_6, 2014/06
no abstracts in English
Sugimoto, Takanori*; Mori, Michiyasu; Toyama, Takami*; Maekawa, Sadamichi
JPS Conference Proceedings (Internet), 3, p.014016_1 - 014016_5, 2014/06
Asai, Shinichiro*; Okazaki, Ryuji*; Terasaki, Ichiro*; Yasui, Yukio*; Igawa, Naoki; Kakurai, Kazuhisa
JPS Conference Proceedings (Internet), 3, p.014034_1 - 014034_6, 2014/06
We have carried out the neutron scattering measurements for a single crystal of LaCoRhO in order to investigate the ferromagnetic ordering induced by Rh substitution for Co of LaCoO. The ordered moment is evaluated to be 0.40.2, which is consistent with the saturation magnetization of LaCoRhO. It indicates that the ferromagnetic ordering of LaCoRhO originates from the short-range ferromagnetic ordering disordered by Rh ions.
Matsuda, Yasuhiro*; Her, J.-L.*; Michimura, Shinji*; Inami, Toshiya; Ebihara, Takao*; Amitsuka, Hiroshi*
JPS Conference Proceedings (Internet), 3, p.011044_1 - 011044_6, 2014/06
Synchrotron X-ray absorption spectroscopy of CeRhSi has been performed in pulsed high magnetic fields of up to 32 T. The Ce valence is slightly larger than 3+ at 5 K and decreases with increasing magnetic above 20 T. The field-induced valence change seems to correspond to the metamagnetic transition in the magnetization process. This phenomena is similar to our previous result on CeRuSi and seems to be common in Ce-based heavy fermion compounds.
Matsumura, Takeshi*; Michimura, Shinji*; Inami, Toshiya; Otsubo, Toru*; Tanida, Hiroshi*; Iga, Fumitoshi*; Sera, Masafumi*
JPS Conference Proceedings (Internet), 3, p.014008_1 - 014008_6, 2014/06
We study the -type antiferro-octupole (AFO) ordered state of CeLaB below 1.5 K by resonant X-ray diffraction in magnetic fields. Multipole moments induced by the field in the AFO phase are identified. In a mean-field model for the AFO order within the quartet crystal-field ground state, the and antiferroquadrupoles (AFQ) are expected as mostly induced AFQ. However, in contrast to this expectation, the main induced moment is found to be the -type AFQ.