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Moribayashi, Kengo
no journal, ,
no abstracts in English
Agui, Akane; Matsumoto, Sayaka*; Sakurai, Hiroshi*; Homma, Satoshi*; Tsuji, Naruki*; Sakurai, Yoshiharu*; Ito, Masayoshi*
no journal, ,
no abstracts in English
Kumada, Takayuki; Karavitis, M.*; Goldschleger, I.*; Apkarian, A.*
no journal, ,
We studied time-resolved CARS study of vibrational coherence in solid phase using iodine molecules in solid krypton. We observed the vibrational coherence of iodine molecules for 200 ps corresponding to about 1000 oscillations at 7 K. The rate of decoherence increases with increasing temperature and the number of vibrational quantum state.
Terauchi, Masami*; Takahashi, Hideyuki*; Handa, Nobuo*; Murano, Takanori*; Koike, Masato; Kawachi, Tetsuya; Imazono, Takashi; Koeda, Masaru*; Nagano, Tetsuya*; Sasai, Hiroyuki*; et al.
no journal, ,
no abstracts in English
Koswattage, K.; Shimoyama, Iwao; Sekiguchi, Tetsuhiro; Baba, Yuji; Nakagawa, Kazumichi*
no journal, ,
Boron nitride (BN) attracts attention for hydrogen storage because of nanotube structure and large interaction with hydrogen. Chemical adsorption of atomic hydrogen is interesting for hydrogen storage at room temperature. However, experimental research on the interaction of atomic hydrogen is little due to the difficulty in synthesizing BN nanomaterials. In this work, we studied adsorption of atomic deuterium on a BN thin film as model system of BN nanotubes with diameter of infinity using NEXAFS spectroscopy. BN thin film was formed on Ni(111) surface by exposure of borazine gas at 800 
C. We measured NEXAFS for the BN film before and after reaction with atomic deuterium produced by a tungsten hot filament. While NEXAFS spectra showed clear change at B K-edge, little change was observed at N K-edge. We analyzed these results by density functional theory calculations and clarified that atomic deuterium preferentially adsorbs on B site in BN materials.
Sakai, Toru; Nakano, Hiroki*; Isoda, Makoto*; Okunishi, Koichi*
no journal, ,
The previous study indicated that a magnetization plateau-like behavior at 1/3 of saturation magnetization is a new phenomena, so-called a magnetization ramp. In the present work we investigate a change of the anomalous behavior under the XXZ anisotropy. As a result, we found that as the XXZ anisotropy is varied from the Ising and XY sides, the magnetization plateau vanishes at a critical point.
SR in CeRu
Al
Kambe, Shinsaku; Chudo, Hiroyuki; Tokunaga, Yo; Koyama, Takehide*; Sakai, Hironori; Ito, Takashi; Ninomiya, Kazuhiko; Higemoto, Wataru; Nishioka, Takashi*; Takesaka, Tomoaki*; et al.
no journal, ,
We report zero-field 
SR measurements made at J-PARC on CeRuAl. Below the phase transition temperature 
K, a clear modulation of polarization due to an internal field is observed, indicating that magnetic ordering takes place. Compared with the internal field expected from the effective magnetic moment in the disordered state, the observed internal field at the site is quite small. This indicates that the ordered Ce magnetic moment is small (
) and/or the nearest pair of Ce magnetic moments are mutually anti-parallel. The 
-dependence of the internal field is somewhat peculiar, suggesting that another ordering is taking place as well.
Itakura, Ryuji; Hasegawa, Hirokazu*; Kurosaki, Yuzuru; Yokoyama, Atsushi; Oshima, Yasuhiro*
no journal, ,
When neutral molecules are partly ionized in intense laser fields (I
35 TW/cm
), a hole in the rotational wave packet of the remaining neutral NO is created by the ionization, whose rate depends on the alignment angle of the molecular axis with respect to the laser polarization direction. Rotational state distributions of NO are experimentally observed and then the characteristic feature that the population at higher J levels is increased by the ionization can be identified. Numerical calculation for solving time-dependent rotational Schr
dinger equations including the effect of the ionization is carried out. The numerical results suggest that NO molecules aligned perpendicular to the laser polarization direction are dominantly ionized at the peak intensity of I = 42 TW/cm, where the multiphoton ionization is preferred rather than the tunneling ionization.
Nishikino, Masaharu; Ochi, Yoshihiro; Hasegawa, Noboru; Kawachi, Tetsuya; Oba, Toshiyuki; Kaihori, Takeshi; Nagashima, Keisuke
no journal, ,
no abstracts in English
Iwata, Yoshihiro; Ito, Chikara; Aoyama, Takafumi
no journal, ,
no abstracts in English
-B surface studied by reflection high-energy positron diffractionFukaya, Yuki; Kawasuso, Atsuo
no journal, ,
no abstracts in English
Kawasuso, Atsuo; Maekawa, Masaki; Yabuuchi, Atsushi; Fukaya, Yuki; Mochizuki, Izumi
no journal, ,
no abstracts in English
Mochizuki, Izumi; Fukaya, Yuki; Kawasuso, Atsuo
no journal, ,
Quasi one dimensional (1D) metallic chain of single-atom wide is constructed on the Ge(001) surface by the adsorption of Pt atoms. While the 1D chain is required the elucidation of the electronic properties about the 1D metal or the metal-insulator transition, there is also discussed about the atomic arrangement. The recent results by first-principle calculation suggest the atomic chain is configured by the Ge dimers that so far was admitted that by the Pt dimers, and that is still to be determined. We have measured the reflection high energy positron diffraction (RHEPD) to elucidate the atomic arrangement of the 1D chain. The obtained RHEPD rocking curve does not match the dynamical calculation assuming the Pt dimers, on the other hand that of the Ge dimers is able to reproduce the curve generally better. Although there are needs to optimize the parameters such as atomic positions or Debye temperatures, the RHEPD results show the 1D chain on the Pt/Ge(001) surface is the Ge dimers.
Itami, Toshio; Ara, Kuniaki; Saito, Junichi; Nishimura, Masahiro
no journal, ,
no abstracts in English
Maekawa, Masaki; Kawasuso, Atsuo; Fukaya, Yuki; Yabuuchi, Atsushi
no journal, ,
no abstracts in English
Onishi, Hiroaki
no journal, ,
no abstracts in English
Onishi, Hiroaki; Dagotto, E.*
no journal, ,
no abstracts in English
Nara, Shintaro*; Torigoe, Shuhei*; Hanasaki, Noriaki*; Nogami, Yoshio*; Matsumura, Daiju; Yoshii, Kenji; Yoneda, Yasuhiro; Nishihata, Yasuo
no journal, ,
We have investigated the physical properties of pyrochlore niobates YCaNbO
and NdCaNbO. From synchrotron X-ray absorption and thermogravimetric measurements, the average valence of Nb ion in these oxides was determined as 4.5+, indicating the existence of charge frustration on the Nb site. These oxides have been found to show some intriguing properties such as the absence of magnetic moment of Nb, large thermoelectric effect and ferroelectricity. Possible origins of these phenomena are discussed on the basis of results of X-ray absorption measurements.
Ninomiya, Kazuhiko; Ito, Takashi; Higemoto, Wataru; Kita, Makoto*; Shinohara, Atsushi*; Nagatomo, Takashi*; Kubo, Kenya*; Strasser, P.*; Kawamura, Naritoshi*; Shimomura, Koichiro*; et al.
no journal, ,
Muonic atom is an atom like system that has one negatively charged muon instead of an electron. It is known that the formation process of muonic atom is influenced by the structure of muon capturing molecule (molecular effect). In this study, we performed systematic muon irradiation for low pressure nitrogen oxide samples and discuss the molecular effect on muon capture phenomena.
Mn
O
, 2Matsumoto, Keisuke*; Hoshiyama, Takuya*; Oishi, Daisuke*; Akahama, Hiroshi*; Yoshii, Kenji; Kano, Jun*; Hanasaki, Noriaki*; Kambe, Takashi*; Ikeda, Naoshi*; Mori, Shigeo*
no journal, ,
We have investigated the physical properties of YbFeMnO, a derivative system of the electronic ferroelectric RFeO (R: rare earths). Electron diffraction measurements showed taht long-range charge ordering of the Fe-3d charges was observed at room temperature for x=0; this ordering is the origin of ferroelectricity. The x=0.1 oxide showed diffuse scattering patterns at room temperature, instead of the charge-ordered pattern. Thus, 5% Mn substitution can collapse the long-range charge ordering. We will also present the correlation between the magnetic/dielectric properties and the crystal structure.