NMR in single crystal YbRhSi (H//a)

Kambe, Shinsaku; Sakai, Hironori; Tokunaga, Yo; Lapertot, G.*; Matsuda, Tatsuma*; Knebel, G.*; Flouquet, J.*; Walstedt, R. E.*

no journal, , 

NMR measurements in a single crystalYbRhSi are reported. Previously, the results for H//a have been reported, this time results for H//a are presented. As well as the case for H//c, the coexistence of Fermi and non-Fermi liquid states is observed for H//a, however, the T-and H-dependences are different from those for H//c.

Full-f gyrokinetic simulations of neoclassical toroidal viscosity in perturbed tokamaks

Matsuoka, Seikichi*; Idomura, Yasuhiro; Satake, Shinsuke*

no journal, , 

When non-axisymmetric magnetic perturbations are imposed in axisymmetric tokamaks, broken axisymmetry induces the neoclassical viscosity, and affects momentum transport and resulting plasma rotation profiles. In this work, we estimate the neoclassical toroidal viscosity using full-f gyrokinetic simulations, and verify calculation methods and obtained results. We discuss the parameter dependency of the neoclassical toroidal viscosity in the presence of small resonant magnetic perturbations, based on comparisons against analytic theories and neoclassical transport codes.

Quantum phase transition of the S=1/2 three-leg spin tube

Sakai, Toru; Kasahara, Toshihiro*; Nakano, Hiroki*; Hijii, Keigo*; Okunishi, Koichi*; Okamoto, Kiyomi*

no journal, , 

We report the result from the theoretical study based on the numerical diagonalization and the finite-size scaling analysis, on the quantum phase transition which occurs when the ratio of the rung coupling, the leg coupling and the ring exchange interactions is varied, in the S=1/2 three-leg spin tube.

Hierarchical mixture Learning

Aida, Toshiaki*; Hata, Haruhi; Sasakura, Mariko*; Yokoyama, Kaoru

no journal, , 

"Gaussian Mixture Learning" is a well-known method to infer the probability distribution from a set of coordinate data it generated. In this study, a mixture distribution is composed of complex mixture ones, and generates the data we observe. Then, we estimate "the mixture ratio among mixture distributions" and "the ratio and parameters of elemental distributions in each mixture" from the data. Our approach is based on the hierarchical formulation of Gaussian Mixture Learning. We discuss and report the effectiveness of this learning method, applying it to the estimation problems of nuclides' components in -ray energy spectra.

High-pressure neutron study on silica glass at J-PARC high-pressure neutron diffractometer PLANET

Hattori, Takanori; Yagafarov, O.*; Katayama, Yoshinori; Chiba, Ayano*; Sano, Asami; Inamura, Yasuhiro; Otomo, Toshiya*; Matsuzaki, Yuki*; Shimojo, Fuyuki*

no journal, , 

PLANET is the beamline dedicated for the high-pressure experiments. The operation has been started at JFY 2013, and now many users are coming to use. In this talk, we introduce the current state of the PLANET and the example of the structure analysis of disordered materials. PLANET adopted the double staged compression system of the multi anvil 6-6, and enables the data collation at 10 GPa and 2000 K. To extend accessible PT range, we newly introduce another compression system of multi-anvil 6-8, and succeeded in generating 16 GPa and 1273 K. In addition, the PLANET is designed so that we can analyze the structure of liquid under pressure. In the analysis, the program for liquid analysis developed at BL21 NOVA is used. Here, we briefly introduce the reliability of the results and the pressure evolution of the silica glass.

In situ stress characterization of Si(111) 77 reconstruction

Asaoka, Hidehito; Uozumi, Yuki; Suzuki, Shota*; Yamaguchi, Kenji

no journal, , 

no abstracts in English

Atomic configuration of Ge(001)-c()-Au surface determined by total-reflection high-energy positron diffraction (TRHEPD)

Mochizuki, Izumi*; Fukaya, Yuki; Wada, Ken*; Maekawa, Masaki; Kawasuso, Atsuo; Shidara, Tetsuo*; Hyodo, Toshio*

no journal, , 

no abstracts in English

Local structure analysis of BiNaTiO

Yoneda, Yasuhiro; Nagamoto, Takeru*; Nagata, Hajime*; Kobune, Masafumi*

no journal, , 

BiNaTiO (BNT) is a candidate for lead-free piezoelectric material having a perovskite-type structure. The crystal structure of BNT was believed to be rhombohedral. Recently, BNT grown by high-temperature synthesis was reported to be monoclinic. We have synthesized BiNaTiO crystal in the high temperature condition so as to apply the Rietveld method for average structure refinement and the atomic pair-distribution function (PDF) technique for local structure refinement. The Bragg peaks can be reproduced by assuming a monoclinic structure, while the local structure can be reproduced by assuming a rhombohedral crystal structure.

Charge-to-spin conversion and spin diffusion in Bi/Ag bilayers observed by spin-polarized positron beam

Zhang, H.; Yamamoto, Shunya; Li, H.; Maekawa, Masaki; Fukaya, Yuki; Kawasuso, Atsuo

no journal, , 

Transport reduction mechanism in negative triangularity tokamak

Kikuchi, Mitsuru; Takizuka, Tomonori*; Furukawa, Masaru*

no journal, , 

While negative triangular tokamak configuration has possibility to improve power handling capability, mechanism of improved confinement observed in TCV is still not fully understood. In this talk, we will summarize present understanding of linear eigenmode structure of toroidal drift waves and also flow shear suppression of turbulence.