SR study of an layered organic superconductor -(BEDT-TTF)HgBr

Sato, Kazuhiko*; Fujita, Hidemi*; Katayama, Kazuhiro*; Taniguchi, Hiromi*; Ito, Takashi; Oishi, Kazuki*; Higemoto, Wataru

Physica B; Condensed Matter, 404(5-7), p.597 - 599, 2009/04

https://doi.org/10.1016/j.physb.2008.11.122

Zero-field muon spin relaxation and high-field transverse muon spin rotation have been measured for an organic superconductor -(BEDT-TTF)HgBr. No anomaly is found in zero-field relaxation spectrum at the superconducting transition temperature, 4.2 K. The muon Knight shift determined by transverse muon spin rotation at 6 T exhibits Curie-Weiss like behavior down to 2 K, whereas static magnetic susceptibility shows a peak around 30 K. The muon Knight shift does not scale with the magnetic susceptibility at low temperatures.

SR study of an antiferromagnetic insulator (BEDT-TTF)(TCNQ)

Sato, Kazuhiko*; Fujita, Hidemi*; Sato, Ryosuke*; Taniguchi, Hiromi*; Higemoto, Wataru

Physica B; Condensed Matter, 374-375, p.102 - 105, 2006/03

https://doi.org/10.1016/j.physb.2005.11.026

Zero-field SR measurements for an antiferromagnetic Mott insulator (BEDT-TTF)(TCNQ) were performed in order to study the microscopic magnetic properties of this organics. Slight increase of the relaxation rate is observed below 20K owing to the antiferromagnetic ordering of BEDT-TTF dimers, whereas clear muon precession signal is observed below 3K owing to the antiferromagnetic ordering of TCNQ. Below 3K, there exist at least two antiferromagnetic domains whose volume fractions changes with temperature.

Evaluation of Coupled Thermo-Hydro-Mechanical Phenomena in the Near Field for Geological Disposal of High-Level Radioactive waste

Chijimatsu, Masakazu*; Fujita, Tomoo; Sugita, Yutaka; Taniguchi, Wataru

JNC TN8400 2000-008, 339 Pages, 2000/01

JNC-TN8400-2000-008.pdf:30.96MB

Geological disposal of high-level radioactive waste (HLW) in Japan is based on a multibarrier system composed of engineered and natural barriers. The engineered barriers are composed of vitrified waste confined within a canister, overpack and buffer material. Highly compacted bentonite clay is considered one of the most promising candidate buffer material mainly because of its low hydraulic conductivity and high adsorption capacity of radionuclides. In a repository for HLW, complex thermal, hydraulic and mechanical (T-H-M) phenomena will take place, involving the interactive processes between radioactive decay heat from the vitrified waste, infiltration of ground water and stress generation due to the earth pressure, the thermal loading and the swelling pressure of the buffer material. In order to evaluate the performance of the buffer material, the coupled T-H-M behaviors within the compacted bentonite have to be modelled. Before establishing a fully coupled T-H-M model, the mechanism of each single Phenomenon or partially coupled phenomena should be identified. Furthermore, in order to evaluate the coupled T-H-M phenomena, the analysis model was developed physically and numerically and the adequacy and the applicability was tested though the engineered scale laboratory test and in-situ test. In this report, the investigative results for the development of coupled T-H-M model were described. This report consists of eight chapters. In Chapter l, the necessity of coupled T-H-M model in the geological disposal project of the high-level radioactive waste was described. In Chapter 2, the laboratory test results of the rock sample and the buffer material for the coupled T-H-M analysis were shown. The rock samples were obtained from the in-situ experimental site at Kamaishi mine. As the buffer material, bentonite clay (Kunigel V1 and Kunigel OT-9607) and bentonite-sand mixture were used. In Chapter 3, in-situ tests to obtain the rock property were shown. As ...

Data collection by literature survey on rock physical properties in Japan (II)

Sato, Toshinori; Taniguchi, Wataru; Fujita, Tomoo; Hasegawa, Hiroshi

JNC TN7400 99-011, 36 Pages, 1999/12

JNC-TN7400-99-011.pdf:1.55MB

In order to understand the general thermal and mechanical properties of rock masses and initial stress of rock at depth, data were compiled from the published literature in Japan and collected from investigations carried out at Kamaishi mine and Tono mine. Statistical examinations derived the ranges, means and medians of the mechanical properties for the different rock types. It was confirmed that the correlations between the mechanical properties were in agreement with correlations determined previously in other similar surveys. The unconfined compressive strength of Neogene sedimentary rocks showed a tendency to increase with increasing depth ( 500 m). An examination of the measured initial stress data collected through literature surveys showed that the vertical stress can be approximated by the extent of gravitational loading at a particular point. There is an approximately linear relationship between the average stress in a horizontal plane and the depth. The lateral pressure coefficient tends to have a high value and large range at shallow depths, but tends towards 1 with increasing depth.

Sensitivity analysis of temperature distributions in deep geological repository for high-level radioactive waste

Taniguchi, Wataru; Fujita, Tomoo; Kanno, Takeshi; Ishikawa, Hirohisa;

Proceedings of 8th International Topical Meeting on Nuclear Reactor Thermal-Hydraulics (NURETH-8), 0 Pages, 1997/00

None

Chopper-type neutron inelastic spectrometer 4SEASONS at MLF, J-PARC

Kajimoto, Ryoichi; Yokoo, Tetsuya*; Nakamura, Mitsutaka; Nakajima, Kenji; Inamura, Yasuhiro; Takahashi, Nobuaki; Maruyama, Ryuji; Soyama, Kazuhiko; Mizuno, Fumio; Shibata, Kaoru; et al.

no journal, , 

no abstracts in English

Current status of the chopper spectrometer 4SEASONS at J-PARC

Kajimoto, Ryoichi; Nakamura, Mitsutaka; Yokoo, Tetsuya*; Inamura, Yasuhiro; Mizuno, Fumio; Nakajima, Kenji; Takahashi, Nobuaki; Kawamura, Seiko; Maruyama, Ryuji; Soyama, Kazuhiko; et al.

no journal, , 

no abstracts in English

The Fermi-chopper spectrometer 4SEASONS at J-PARC

Kajimoto, Ryoichi; Nakamura, Mitsutaka; Yokoo, Tetsuya*; Inamura, Yasuhiro; Mizuno, Fumio; Nakajima, Kenji; Takahashi, Nobuaki; Kawamura, Seiko; Maruyama, Ryuji; Soyama, Kazuhiko; et al.

no journal, , 

no abstracts in English

The Fermi-chopper spectrometer 4SEASONS

Kajimoto, Ryoichi; Nakamura, Mitsutaka; Yokoo, Tetsuya*; Inamura, Yasuhiro; Mizuno, Fumio; Nakajima, Kenji; Takahashi, Nobuaki; Kawamura, Seiko; Maruyama, Ryuji; Soyama, Kazuhiko; et al.

no journal, , 

no abstracts in English