Keiichi Yokogawa

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A pressure transmitting medium named Daphne 7474, which solidifies at P(s)=3.7 GPa at room temperature, is presented. The value of P(s) increases almost linearly with temperature up to 6.7 GPa at 100 degrees C. The high pressure realized by a medium at the liquid state allows a higher limit of pressurization, which assures an ideal hydrostatic pressure. We(More)
Dependence of the superconducting transition temperature (T(c)) and critial superconducting pressure (P(c)) of the pressure-induced superconductor β-(BDA-TTP)(2)I(3) [BDA-TTP = 2,5-bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene] on the orientation of uniaxial strain has been investigated. On the basis of the overlap between the upper and lower bands(More)
We report the crystal structure and physical properties of the 2:1 FeCl4- salt of a new donor molecule, EDO-TTFVO. Crystal structure analysis of this salt revealed that the donor molecules formed a beta' '-type two-dimensional conducting layer, and there is a short S...Cl contact between the donor molecules and the FeCl4- ions, which is expected to mediate(More)
The 2:1 salts of a new donor molecule, EDT-DSDTFVO with MX4- (M = Fe, Ga; X = Cl, Br) ions, were prepared. The crystal structures of the donor molecules had a beta-type packing motif. All the salts essentially exhibited metallic behaviors despite the small upturns in the resistances below 30-70 K. A large negative magnetoresistance (MR) effect [-14.7%(More)
A pressure vessel for tensile testing has been developed to measure tensile stress in high-pressure up to 50.5 MPa at elevated temperatures up to 773 K. The vessel is designed to facilitate the measurement of the actual tensile load on the specimen by an external load cell without the influence of axial stress due to high pressure in the vessel and the(More)
A new type of apparatus for material tests using an internal loading system in high-pressure gas up to 100 MPa at room temperature without conventional material testing equipment was developed. The apparatus consists of a high-pressure control system and a pressure vessel, in which a piston is installed in the cylinder of the pressure vessel. The load(More)
Takeshi Rachi,1 Harukazu Yoshino,2 Ryotaro Kumashiro,1 Masaki Kitajima,2 Kensuke Kobayashi,2 Keiichi Yokogawa,2 Keizo Murata,2 Noriaki Kimura,3 Haruyoshi Aoki,3 Hiroshi Fukuoka,4 Syoji Yamanaka,4 Hidekazu Shimotani,5 Taishi Takenobu,5 Yoshihiro Iwasa,5 Takahiko Sasaki,6 Norio Kobayashi,6 Yuji Miyazaki,7 Kazuya Saito,8 FangZhun Guo,9 Keisuke Kobayashi,9(More)
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