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AsIkeda, Shugo*; Tsuchiya, Yu*; Zhang, X.-W.*; Kishimoto, Shunji*; Kikegawa, Takumi*; Yoda, Yoshitaka*; Nakamura, Hiroki; Machida, Masahiko; Glasbrenner, J.*; Kobayashi, Hisao*
Physical Review B, 98(10), p.100502_1 - 100502_6, 2018/09
Times Cited Count：6 Percentile：25.82(Materials Science, Multidisciplinary)The interplay between magnetism and superconductivity is one of important subjects to investigate the pairing mechanism in novel superconductors. We have found new coexistence between an antiferromagnetic order in the Fe sublattice and superconductivity of the FeAs-based EuFeAs superconductor in the pressure range from 2.4 to 3.0 GPa by 
Fe nuclear forward scattering (NFS) using a single crystal sample. The magnetic state in the Fe sublattice changes to a new antiferromagnetic one with superconductivity from a stripe-type antiferromagnetic one observed in normal conducting state at 2.7 GPa. Below the superconducting transition temperature, the temperature dependence of Fe NFS spectra reveals that the new antiferromagnetic order develops with the superconductivity. This non-trivial coupling of two ordered states in EuFeAs under pressure demonstrates a new and intriguing relationship between magnetism and superconductivity in Fe-based superconductors.
Matsukawa, Makoto; Kikuchi, Mitsuru; Fujii, Tsuneyuki; Fujita, Takaaki; Hayashi, Takao; Higashijima, Satoru; Hosogane, Nobuyuki; Ikeda, Yoshitaka; Ide, Shunsuke; Ishida, Shinichi; et al.
Fusion Engineering and Design, 83(7-9), p.795 - 803, 2008/12
Times Cited Count：17 Percentile：72.86(Nuclear Science & Technology)no abstracts in English
have an anomalous endohedral structure? Synthesis and single crystal X-ray structure of the carbene adductAkasaka, Takeshi*; Kono, Takayoshi*; Takematsu, Yuji*; Nikawa, Hidefumi*; Nakahodo, Tsukasa*; Wakahara, Takatsugu*; Ishitsuka, Midori*; Tsuchiya, Takahiro*; Maeda, Yutaka*; Liu, M. T. H.*; et al.
Journal of the American Chemical Society, 130(39), p.12840 - 12841, 2008/10
Times Cited Count：76 Percentile：84.42(Chemistry, Multidisciplinary)We report here the results on single crystal X-ray crystallographic analysis of the Gd@C carbene adduct (Gd@C(ad), Ad=adamantylidene). The Gd atom in Gd@C(Ad) is located at an off-centered position near a hexagonal ring in the C2v-C cage, as found for M@C (M = Sc and La) and La@C(Ad). Theoretical calculation also confirms the position of the Gd atom in the X-ray crystal structure.
Tsuchiya, Katsuhiko; Suzuki, Yutaka; Kizu, Kaname; Yoshida, Kiyoshi; Tamai, Hiroshi; Matsukawa, Makoto; Dolgetta, N.*; Portafaix, C.*; Zani, L.*; Pizzuto, A.*
IEEE Transactions on Applied Superconductivity, 18(2), p.208 - 211, 2008/06
Times Cited Count：7 Percentile：42.45(Engineering, Electrical & Electronic)Magnet system in JT-60SA consists of 18 toroidal field coils, 7 plasma equilibrium field (EF) coils, and central solenoid (CS) that has 4 modules of solenoids. Mechanical design of EF coils and CS is optimized in order to obtain the broad operational space of plasmas that are double-null plasma with high plasma current for high performance operation and ITER-like configuration with IP=3.5MA for ITER-relevant experiment. In the former design, called NCT, divertor coil (EF4) is made of Nb
Sn conductor, as well as CS conductor. However, it is clear that 6.2T of Bmax is significant to operate ITER-like plasma. Therefore, material of cable for EF4 conductor is changed into NbTi, so that this contributes to cost reduction. Regarding CS design, material of conduit is changed into JK2LB in order to simplify the structure of pre-compression. Stress analysis for support structure and winding pack of EF coils and CS is currently carried out. In the case where the vertical unbalance force of CS is largest in the designed plasma operation, peak stress of conduit is less than fatigue limit in 18,000 cycles that is designed number of plasma shot in JT-60SA. This result shows the recent design of CS conductor has significant mechanical strength.
Fujita, Takaaki; Tamai, Hiroshi; Matsukawa, Makoto; Kurita, Genichi; Bialek, J.*; Aiba, Nobuyuki; Tsuchiya, Katsuhiko; Sakurai, Shinji; Suzuki, Yutaka; Hamamatsu, Kiyotaka; et al.
Nuclear Fusion, 47(11), p.1512 - 1523, 2007/11
Times Cited Count：24 Percentile：63.28(Physics, Fluids & Plasmas)Design of modification of JT-60U, JT-60SA, has been optimized in viewpoint of plasma control, and operation regimes have been evaluated. Upper and lower divertors with different geometry are prepared for flexibility of plasma shape control. The beam lines of negative-ion NBI are shifted downward for off-axis current drive, in order to obtain a weak/reversed shear plasma. The feedback control coils along the port hole in the stabilizing plate are found effective to suppress the resistive wall mode (RWM) and sustain high 
close to the ideal wall limit. The regime of full current drive operation has been extended with upgraded heating and current drive power. Full current drive operation for 100 s with reactor-relevant high values of normalized beta and bootstrap current fraction (
= 2.4 MA, = 4.4, 
= 0.70, 
/
= 0.86, H
= 1.3) is expected in a highly-shaped low-aspect-ratio configuration (
= 2.65). High , high-density ELMy H-mode is also expected.
Tamai, Hiroshi; Fujita, Takaaki; Kikuchi, Mitsuru; Kizu, Kaname; Kurita, Genichi; Masaki, Kei; Matsukawa, Makoto; Miura, Yukitoshi; Sakurai, Shinji; Sukegawa, Atsuhiko; et al.
Fusion Engineering and Design, 82(5-14), p.541 - 547, 2007/10
Times Cited Count：9 Percentile：54.87(Nuclear Science & Technology)JT-60SA is positioned as the ITER satellite tokamak to conduct research elements to support and supplement ITER towards DEMO under the joint collaboration of Japan and EU. After the discussions in JA-EU Satellite Tokamak Working Group in 2005, the heating power is increased up to 41MW, 100s to ensure the ITER support research. With such increased heating power, the prospective plasma performances are analysed by the equilibrium and transport analysis codes. Operation window of a fully non-inductive current drive is extended to high density region. Simultaneous achievement of high equivalent Q
and high normalised beta is also expected in wide operational margin. Those prospects strongly indicate that JT-60SA is suitable machine to conduct the advanced research orienting to ITER and DEMO.
Tsuchiya, Katsuhiko; Suzuki, Yutaka; Kizu, Kaname; Yoshida, Kiyoshi; Tamai, Hiroshi; Matsukawa, Makoto
no journal, ,
no abstracts in English
Tsuchiya, Katsuhiko; Edaya, Masahiro; Suzuki, Yutaka; Kizu, Kaname; Yoshida, Kiyoshi; Matsukawa, Makoto
no journal, ,
no abstracts in English
AsFukuda, Tatsuo; Kobayashi, Hisao*; Ikeda, Shugo*; Tsuchiya, Yu*; Tsutsui, Satoshi*; Baron, A. Q. R.*; Nakamura, Hiroki; Machida, Masahiko
no journal, ,
no abstracts in English
