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Moribayashi, Kengo
no journal, ,
no abstracts in English
Shimoyama, Iwao; Baba, Yuji; Sekiguchi, Tetsuhiro; Nath, K. G.*
no journal, ,
no abstracts in English
Sato, Shinichiro; Oshima, Takeshi
no journal, ,
no abstracts in English
O
Agui, Akane; Nagata, Tomoko*; Mizumaki, Masaichiro*; Ikeda, Naoshi*
no journal, ,
no abstracts in English
Kubo, Katsunori
no journal, ,
no abstracts in English
Miyato, Naoaki; Scott, B. D.*; Yagi, Masatoshi
no journal, ,
Since perturbations with short wavelength and small amplitude are considered in the standard gyrokinetic formulation, there is no reason why the standard model is still valid in the long wavelength regime. So far, we clarified by reviewing the gyrokinetic formulation in the electrostatic limit that the high-order displacement vector associated with the guiding-centre transform, which is neglected in the standard formulation, should be considered in the long wavelength regime. This time we reconsider the electromagnetic gyrokinetic model with shear Alfv
n perturbation (
) in which the parallel canonical momentum (
) is one of velocity variables. The symplectic part of the model has the same form as the electrostatic one and we can apply the same guiding-centre transformation as the electrostatic case. However, the gyrokinetic Hamiltonian is modified by the magnetic perturbations.
Shibata, Kaoru*; Takahashi, Nobuaki; Yamada, Takeshi*; Kamazawa, Kazuya*; Kawakita, Yukinobu; Nakajima, Kenji; Kambara, Wataru; Inamura, Yasuhiro; Nakatani, Takeshi; Aizawa, Kazuya; et al.
no journal, ,
no abstracts in English
Onishi, Hiroaki
no journal, ,
no abstracts in English
Kokubo, Nobuhito*; Okayasu, Satoru; Tamochi, Hirotaka*; Shinozaki, Bunju*
no journal, ,
In a mesoscopic superconductor, characteristic configurations of quantum vortices, such as polybonal structures or shell structures, can be observed. We have been investigating the votices configurations in amorphous MoGe mesoscopic diskform superconductors using a scanning SQUID microscope. In this study, we expand our research objects to 80
m 
80m square-shaped superconductors. The vortices configurations appear with the different symmetries from the circular case.
-ray generation from laser-plasmasNakamura, Tatsufumi; Koga, J. K.; Esirkepov, T. Z.; Kando, Masaki; Korn, G.*; Bulanov, S. V.
no journal, ,
Radiation reaction (RR) effect, which is a back reaction acting on a charged particle which emits radiation due to its acceleration, is important for such as electrons in synchrotron accelerators or high energy charged particles in the universe. For electrons irradiated by intense laser pulse, RR effect has been neglected so far, but as the laser intensity increases beyond roughly 
W/cm
, it is expected to play an important role. In this study we investigated -ray generation via RR effect. When irradiating 10 PW, 30 fs laser pulse onto thin layer of carbon target, -ray which is as short as the laser pulse, and the total energy is 96 J which is 32% of the incident laser pulse is generated. The -ray power of 2.8 PW which is much higher than those generated by any other devices. We discuss the possibility of laser-driven -ray source.
Yoneda, Yasuhiro; Kohara, Shinji*
no journal, ,
NaNbO has expected as an end member of unleaded piezoelectric material is a ferroelectric material studied widely. It is considered as the antiferroelectric crystal at room temperature, and the phase transition of 3 times is shown by the melting point from room temperature. Although the structure of the antiferroelectric phase in room temperature is orthorhombic 
, the atom position of this structure is very close to rhombohedral 
. By doping Li, it is possible to also make this hidden rhmbohedral structure appear. We examined the phase transition and the Li dope effect of NaNbO from local order analysis using atomic pair-distribution function (PDF). It is thought that the randomness of 
site is suppressed by Li like AgNbO, and the structure which is a ferroelectric phase stabilizes NaNbO from the result of local order analysis.
Yokota, Terufumi
no journal, ,
no abstracts in English
Hijii, Keigo; Sakai, Toru
no journal, ,
We investigate the ground state phase diagram and properties of the frustrated three-leg S=1/2 quantum spin ladder systems. We make the ground state phase diagram clear using the exact diagonalization. And we find out magnon bound states in the nontrivial intermediate phase.
Ieda, Junichi; Yamane, Yuta*; Maekawa, Sadamichi
no journal, ,
Spinmotive force is a new concept in the field of spin transport. To produce the spinmotive force it is required that the magnetization depends both on time and space. A DW motion in a uniform nanowire driven by a DC magnetic field generates a DC spinmotive force. The ferromagnetic resonance in a comb-shaped thin film and the vortex core gyration in a disk excited by AC magnetic fields generate a DC and AC spinmotive forces, respectively. In this study, by using a periodically modulated nanowire we demonstrate that the AC spinmotive force can be generated by applying a DC magnetic field. We also discuss the field- and shape-dependence of the output AC signals.
Maekawa, Masaki; Kawasuso, Atsuo; Fukaya, Yuki; Mochizuki, Izumi; Zhang, H.
no journal, ,
no abstracts in English
Mori, Michiyasu; Hikino, Shinichi*; Koshibae, Wataru*; Maekawa, Sadamichi
no journal, ,
no abstracts in English
Si-NMR study of URuSiSakai, Hironori; Tokunaga, Yo; Kambe, Shinsaku; Urbano, R. R.*; Kuhns, P. L.*; Reyes, A. P.*; Ronning, F.*; Bauer, E. D.*; Thompson, J. D.*
no journal, ,
The heavy fermion superconductor URuSi with 
K shows the "hidden order" at 
K. Below 1 K, it shows a first-order-transition at 
T from the hidden order phase to the magnetically ordered phase. The 
-
phase diagram for URuSi above 35 T is known to be complicated but the details in the each phase above 35 T are unknown. We have been investigating the electronic state by means of Si-NMR in the higher field. The NMR experiment was done at National High Magnetic Field Laboratory (Tallahassee, FL, U.S.A.).
GaBSakai, Hironori; Tokunaga, Yo; Kambe, Shinsaku; Baumbach, R. E.*; Ronning, F.*; Bauer, E. D.*; Thompson, J. D.*
no journal, ,
Tetragonal CeRuGaB has been recently found to be a ferromagnet with 
K. The static and dynamic magnetic anisotropy in this system has been investigated by means of 
Ga- and 
B-nuclear magnetic resonance (NMR).
(Sr,Ba)
CuO
Wakimoto, Shuichi; Ishii, Kenji; Kimura, Hiroyuki*; Ikeuchi, Kazuhiko*; Yoshida, Masahiro*; Adachi, Tadashi*; Koike, Yoji*; Fujita, Masaki*; Yamada, Kazuyoshi*; Mizuki, Junichiro
no journal, ,
We performed resonant inelastic X-ray scattering at Cu-K absorption edge to study charge excitations in hole-doped high-Tc cuprate La(Sr,Ba)CuO. By subtracting elastic and molecular orbital excitation components from RIXS spectra, we have found dispersing charge excitation below 4 eV. This is the first success of observation of intra-band excitation which reflects dynamical charge-charge correlation function in the hole-doped system.