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Metoki, Naoto; Yamauchi, Hiroki; Matsuda, Masaaki*; Fernandez Baca, J.*; Yoshida, Masahiro*; Yoshizawa, Hideki*; Hagihara, Masato*; Watanuki, Ryuta*
no journal, ,
We report the magnetic structures and propose the mechanism of the successive transition based on the 
-electron state revealed by CEF excitation. We confirmed the non-collinear `all-in all-out' structure (
) of the in-plane moment. We found that the magnetic moment along the 
-axis 
showed diagonally antiferromagnetic structure (
). The unusual magnetic ordering is phenomenologically understood via Landau theory. We also found that a long-period incommensurate modulation of the (
) antiferromagnetic structure of with the propagation 
= (0.14, 0.14, 0.1) and 
= (0.2, 0, 0.1) in phase III and IV, respectively. We found pseudo-quartet -electron state based on 
and 
. We can propose the intermediated phase as the magnetically ordered phase of 
while 
and 
coupling phase tabilized in low temperatures.
SiKambe, Shinsaku; Hattori, Taisuke; Sakai, Hironori; Tokunaga, Yo; Matsuda, Tatsuma*; Haga, Yoshinori; Walstedt, R. E.*
no journal, ,
High quality YbRh
Si was prepared by concentrating the 
Si isotope which is the NMR nucleus by 52%. Since the natural abundance ratio of Si isotope is about 4%, this concentration can shorten the measured integrated time to about one hundredth. Using this single crystal sample, NMR spin echo attenuation was measured. In the decay curve, in addition to ordinary Gauss type and Lorentz type attenuation, clear vibration term appeared. This is thought to be due to RK interaction and quasi-dipolar interaction. A large temperature change was also observed in this frequency at low temperature. This means that the Fermi surface is temperature dependent. Discuss these behaviors.
Matsubara, Akihiro*; Fujita, Natsuko; Ishii, Kunikazu*
no journal, ,
no abstracts in English
Yokota, Terufumi
no journal, ,
no abstracts in English
Fe
O
Shamoto, Shinichi; Ito, Takashi; Onishi, Hiroaki; Matsuura, Masato*; Akatsu, Mitsuhiro*; Nakamura, Mitsutaka; Inamura, Yasuhiro; Kodama, Katsuaki; Kawamura, Seiko; Nemoto, Yuichi*; et al.
no journal, ,
no abstracts in English
Koura, Hiroyuki
no journal, ,
no abstracts in English
O (R: rare earths)Yoshii, Kenji; Nomura, Takuji*; Ikeda, Naoshi*
no journal, ,
The rare-earth iron system RFeO shows ferroelectricity due to charge ordering of iron ions below 330 K. Also, the iron spins shows ferrimagnetism below 250 K and thus becomes multiferroic. Although this system was discovered almost a decade ago, its detailed properties remain unclear. In this study, we have calculated its ground state based on mean-field approximation. Various charge-ordered states have been observed. However, a ferroelectric state was not most stable. This suggests that the ferroelectricity is governed by the other factors such as lattice distortion.
Hayashi, Naoki
no journal, ,
In order to realize stable accelerator operation, it is necessary to understand various interlocked events and take countermeasures. In the J-PARC Linac, many interlocked events which include waveform data of current monitors and beam loss monitors, were recorded and classified to the various pattern. Their counter measures are under consideration. In the RCS (Rapid-Cycling Synchrotron), new processing unit is prepared to record beam current and position date of interlocked event and its future perspective will be reported.
Yoshimoto, Masahiro; Okabe, Kota; Harada, Hiroyuki; Kinsho, Michikazu; Kato, Shinichi*
no journal, ,
The charge exchange multi-turn beam injection scheme is adopted in the J-PARC 3GeV Rapid Cycling Synchrotron Accelerator (RCS) due to achieve 1MW beam power operation. In the conventional multi-turn beam injection scheme, which is provided by only the septum and bump magnets, injecting turn numbers are limited by the beam losses at the septum. On the other hand, charge exchange multi-turn beam injection does not cause the beam losses at the septum; there is no restriction in principle on the injecting turn number. However, high residual doses are observed around the stripper foil. During the charge exchange multi-turn beam injection, not only the injecting beam but also circulating beam hit the foil, and then a large number of secondary particles, namely protons and neutrons, are generated. PHITS simulation results indicate that the secondary particles cause the high residual doses around the foil. To verify this examination, secondary particles measurement is key issue. But injection system is too complex to detect the pure signals of the secondary particles from the stripper foil. Thus, a new independent type foil introducing device is installed in the 100
dump beam transport line in order to construct a simple experimental system for secondary particle measurements. We plan the two experiments by using this system; one is a directly secondary particle detecting method, and the other is a radioactivation analysis method with metal sample pieces. Now, we started the study of how the identification of species and energies of the secondary particles with PHITS code. In this presentation, we report the simulation results of the utility of the radioactivation analysis method.
K
FeAs due to electron correlation effectsMurai, Naoki; Kajimoto, Ryoichi; Suzuki, Katsuhiro*; Nakajima, Masamichi*; Ikeda, Hiroaki*; Ideta, Shinichiro*; Tanaka, Kiyohisa*
no journal, ,
We report inelastic neutron scattering (INS) study of hole-doped iron-based superconductor Ba
K
FeAs (x = 0.25). The INS data show a spin-wave-like dispersive feature, with a zone boundary energy of 200 meV. A random phase approximation (RPA) treatment of the dynamical spin susceptibility, incorporating the band renormalization factor of 3 derived from angle-resolved photoemission spectroscopy (ARPES) measurements on the same sample, provides a reasonable description of the observed spin excitations. This analysis shows that the Fe-3d bandwidth narrowing due to electron correlation is directly reflected in the spin excitation energy scale. We will discuss the current state of our analysis relating the magnetic response to the underlying electronic structure of the materials.
Cs studied with large-scale shell-model calculationsUtsuno, Yutaka; Shimizu, Noritaka*; Homma, Michio*
no journal, ,
no abstracts in English
nanocrystalsYoneda, Yasuhiro; Kunisada, Ryoichi*; Chikada, Tsukasa*; Ueno, Shintaro*; Fujii, Ichiro*; Wada, Satoshi*
no journal, ,
High-energy X-ray diffraction measurements were performed to analyze KNbO nanocrystals. We used KNbO nanocrystals with cubic shape. Moreover, these nanocrystals have cubic structure owing to their small crystal size. Therefore, these nanocrystals are ideal for applying the Scherrer's equation. Crystal-growth mechanism was considered with the crystal size obtained by the Scherrer's equation. It was found the growth mechanism of KNbO by comparing the crystal size and average structure obtained by Rietveld analysis and coherent size obtained by atomic pair-distribution function method.
Nagai, Yuki; Shen, H.*; Qi, Y.*; Liu, J.*; Fu, L.*
no journal, ,
no abstracts in English
Mamiya, Hiroaki*; Oba, Yojiro; Terada, Noriki*; Watanabe, Norimichi*; Hiroi, Kosuke; Shinohara, Takenao; Oikawa, Kenichi
no journal, ,
no abstracts in English
Sakai, Hironori; Hattori, Taisuke; Tokunaga, Yo; Kambe, Shinsaku; Ronning, F.*; Zhu, J.-X.*; Suzuki, Kohei*; Oshima, Yoshiki*; Yokoyama, Makoto*
no journal, ,
Dilute substitutions of non-magnetic dopants Zn can induce a long-ranged antiferromagnetic ordering to a heavy fermion superconductor CeCoIn. We have microscopically investigated the Zn-doped CeCoIn by means of the nuclear quadrupole/magnetic resonance (NQR/NMR) techniques.
SR studies on Ln(OF
)BiS (Ln=Ce,Nd) under a magnetic fieldHigemoto, Wataru; Ito, Takashi; Ooshima, Kohei; Okazawa, Takeshi*; Tomono, Dai*; Mihara, Mototsugu*; Mita, Masaaki*; Higashinaka, Ryuji*; Matsuda, Tatsuma*; Aoki, Yuji*
no journal, ,
no abstracts in English
Idomura, Yasuhiro
no journal, ,
Transient plasma responses due to modulated electron heating are investigated in numerical experiments of ion temperature gradient driven trapped electron mode turbulence using gyrokinetic full-f Eulerian code GT5D. It is found that even with electron heating without particle and momentum sources such as electron cyclotron resonance heating, dominant turbulence is changed from ion turbulence to electron turbulence due to changes of the electron temperature gradient and the temperature ratio, and the resulting turbulent transport produces responses of density and rotation profiles.
SR measurement of single-crystalline SmSIto, Takashi; Higemoto, Wataru; Suzuki, Hiroyuki*; Imura, Keiichiro*; Sato, Noriaki*
no journal, ,
no abstracts in English
Kofu, Maiko
no journal, ,
no abstracts in English
Otani, Masashi*; Kondo, Yasuhiro; Kitamura, Ryo*; Nakazawa, Yuga*; Sue, Yuki*; Bae, S.*; Choi, S.*; Hasegawa, Kazuo; Iinuma, Hiromi*; Kawamura, Naritoshi*; et al.
no journal, ,
Muon acceleration is an important technique in exploring the new frontier of physics. A new measurement of the muon dipole moments is planned in J-PARC using the muon linear accelerator. The muon acceleration test using a Radio-Frequency Quadrupole linac (RFQ) have been conducted and succeeded to accelerate muon using RF accelerator for the first time. In this paper, the future prospect muon acceleration after this experiment is described.