2021/12/26 更新

写真a

コンドウ リュウスケ
近藤 隆祐
KONDO Ryusuke
所属
自然科学学域 准教授
職名
准教授
外部リンク

学位

  • 博士(学術) ( 東京大学 )

  • 修士(工学) ( 東京大学 )

研究キーワード

  • Structure and electronic properties of organic conductors

  • 極限下(低温・強磁場・高圧縮(静水圧・一軸性))の物性測定・構造解析

  • 有機伝導体の開発

研究分野

  • 自然科学一般 / 半導体、光物性、原子物理

  • 自然科学一般 / 磁性、超伝導、強相関系

学歴

  • 東京大学大学院   総合文化研究科広域科学専攻   相関基礎科学系

    1996年4月 - 1998年2月

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    国名: 日本国

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  • 東京大学   Faculty of Liberal Arts  

    - 1998年

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  • 東京大学大学院   工学系研究科   物理工学専攻

    1994年4月 - 1996年3月

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    国名: 日本国

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  • 東京大学   Graduate School, Division of Engineering  

    - 1996年

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  • 東京大学   The Faculty of Engineering   Department of Applied Physics

    1992年4月 - 1994年3月

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経歴

  • 岡山大学   自然科学研究科数理物理専攻   准教授

    2012年1月 - 現在

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  • 東京大学   広域科学専攻相関基礎科学系   助教

    2007年4月 - 2011年12月

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  • 東京大学   広域科学専攻相関基礎科学系   助手

    1998年2月 - 2007年3月

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  • - Research Associate, School of Arts and Sciences, University of Tokyo

    1998年2月

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所属学協会

 

論文

  • Spin Dynamics in the Mixed Stack Charge Transfer Complex, (BEDO-TTF)(Cl2TCNQ) 査読

    Ko-ichi Hiraki, Masashi Takahashi, Toshihiro Takahashi, Tatsuo Hasegawa, Ryusuke Kondo, Seiichi Kagoshima

    Journal of the Physical Society of Japan   89 ( 7 )   074706 - 074706   2020年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Japan Society of Applied Physics  

    DOI: 10.7566/jpsj.89.074706

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  • Multiple charge density waves compete in ternary rare-earth nickel carbides,RNiC2(R: Y, Dy, Ho, and Er) 査読

    H. Maeda, Ryusuke Kondo, Y. Nogami

    PHYSICAL REVIEW B   100   104107   2019年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

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  • Possible charge order structure of stoichiometric YbFe2O4 査読

    Kosuke Fujiwara, Tomoyuki Karasudani, Mamoru Fukunaga, Hiroyuki Kobayashi, Jun Kano, Pierre-Eymeric Janolin, Jean-Michel Kiat, Yoshio Nogami, Ryusuke Kondo, Naoshi Ikeda

    FERROELECTRICS   512 ( 1 )   85 - 91   2017年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:TAYLOR & FRANCIS LTD  

    We report a possible charge ordering model of triangular mixed valence material YbFe2O4. It was found that a crystal synthesized with high stoichiometry on iron vacancy shows new and simple extinction rule in the superlattice reflections. The Laue class of the diffraction signal is expressed as 2/m. With the consideration of the charge neutrality and the superlattice signal of (1/3 1/3 0), we derived 5 possible charge ordering models of this material.

    DOI: 10.1080/00150193.2017.1349945

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  • Interplay of Charge-Density Wave and Magnetic Order in Ternary Rare-Earth Nickel Carbides, RNiC2 (R = Pr and Nd) 査読

    Nobuki Yamamoto, Ryusuke Kondo, Hiroyuki Maeda, Yoshio Nogami

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   82 ( 12 )   2013年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PHYSICAL SOC JAPAN  

    The electrical and structural properties of NdNiC2 and PrNiC2 are examined in single-crystalline samples in order to investigate the interplay of charge-density wave (CDW) and magnetic order in ternary rare-earth nickel carbides, RNiC2, where R is a rare-earth element. PrNiC2 (no magnetic order down to 1.5 K) and NdNiC2 [antiferromagnetic (AF) transition at 17.2 K] show resistance anomalies at 89 and 121 K, respectively, which are revealed to be CDW transitions by observing X-ray satellite reflections. NdNiC2 also shows a gradual decrease in both resistivity and CDW amplitude below the Neel temperature. In the AF phase, the magnetoresistance sharply decreases where a ferromagnetic (FM) order occurs, which is realized above the spin-flop magnetic field. These results clearly suggest that the relationships between CDW and magnetic order in RNiC2 depend on whether the magnetic order is AF or FM.

    DOI: 10.7566/JPSJ.82.123701

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  • Reproducible synthetic method for the topological superconductor Cu xBi2Se3 査読

    Ryusuke Kondo, Taiki Yoshinaka, Yoshinori Imai, Atsutaka Maeda

    Journal of the Physical Society of Japan   82 ( 6 )   2013年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We report a reproducible synthetic method for superconducting Cu-intercalated Bi2Se3 by an improved melt growth method. Avoiding the production of Cu2Se, which has a higher melting point than that of Bi2Se3, and quenching Cu- Bi-Se mixtures at the liquid phase are keys to obtaining good superconducting samples in a reproducible manner. © 2013 The Physical Society of Japan.

    DOI: 10.7566/JPSJ.82.063702

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  • Superconductivity at 5.4 K in beta-Bi2Pd 査読

    Yoshinori Imai, Fuyuki Nabeshima, Taiki Yoshinaka, Kosuke Miyatani, Ryusuke Kondo, Seiki Komiya, Ichiro Tsukada, Atsutaka Maeda

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   81 ( 11 )   2012年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PHYSICAL SOC JAPAN  

    We investigate bulk superconductivity in a high-quality single crystal of Bi2Pd (beta-Bi2Pd; space group: I4/mmm) with a superconducting transition temperature of 5.4 K, by exploring its electrical resistivity, magnetic susceptibility, and specific heat. The temperature dependence of the electrical resistivity shows convex-upward behavior at temperatures greater than 40-50 K, which can be explained using a parallel-resistor model. In addition, the temperature dependences of the upper critical magnetic field and the specific heat suggest that beta-Bi2Pd is a multiple-band/multiple-gap superconductor.

    DOI: 10.1143/JPSJ.81.113708

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  • Ultrafast photo-induced insulator-to-metal transition in the spin density wave system of (TMTSF)(2)PF6 査読

    Shinichi Watanabe, Ryusuke Kondo, Seiichi Kagoshima, Ryo Shimano

    PHYSICA B-CONDENSED MATTER   405 ( 11 )   S360 - S362   2010年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    We demonstrate a photo-induced insulator-to-metal (I-M) transition in an organic linear chain compound (TMTSF)(2)PF6 [bis-(tetramethyl-tetraselenafulvalene)hexafluorophosphate] in the spin-density-wave (SOW) ground state by optical pump and terahertz probe experiments We observe the collapse of SOW gap in the optical conductivity spectrum at 3 ps after the photo-excitation indicating the ultrafast I-M transition in the SOW system Temporal evolution of the terahertz reflectivity change shows that the photo-induced metallic state sustains longer than 400 Ps (C) 2009 Elsevier B V All rights reserved

    DOI: 10.1016/j.physb.2009.10.063

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  • Electronic states of organic quasi-two dimensional conductor beta ''-(DODHT)(2)PF6 center dot Charge ordering and superconductivity 査読

    M. Higa, R. Kondo, A. Murata, S. Kagoshima, H. Nishikawa, K. Yakushi

    PHYSICA B-CONDENSED MATTER   405 ( 11 )   S172 - S175   2010年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    In the title compound we made X-ray satellite reflection measurements up to 0 7 GPa and angle-dependent magnetoresistance (AMR) measurements at 1 9 GPa The purpose of the study is to clarify (1) how large the temperature-pressure regime is for the long-range charge ordering (CO) (2) whether or not the high pressure regime for the superconductivity is really a metallic state and (3) what the electronic properties are in the intermediate pressure regime between the long-range CO and the superconducting states The long-range CO was found to be stable up to 0 7 GPa and its temperature-pressure regime coincides with that expected from transport measurements AMR at 1 9 GPa 1 4K and 12T suggests the presence of Fermi surfaces consistent with band calculations based on X-ray structural analyses at room temperature and the same pressure Raman studies by one of the authors (K Y) suggest the presence of metallic state in the intermediate pressure regime where the resistance shows apparently insulating properties Discussion is made on the role of the charge-degree of freedom in causing the superconductivity (C) 2009 Elsevier B V All rights reserved

    DOI: 10.1016/j.physb.2009.11.092

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  • Interplay of charge-density waves and superconductivity in the organic conductor β"-(BEDT-TTF)2AuBr2

    Ryusuke Kondo, Momoka Higa, Seiichi Kagoshima, Noriaki Hanasaki, Yoshio Nogami, Hiroyuki Nishikawa

    Phys. Rev. B   81 ( 2 )   024519   2010年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1103/PhysRevB.81.024519

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  • Effects of Hydrostatic Pressure and Uniaxial Strain on Spin-Peierls Transition in an Organic Radical Magnet, BBDTA center dot InCl4 査読

    Masaki Mito, Seiichiro Kawagoe, Hiroyuki Deguchi, Seishi Takagi, Wataru Fujita, Kunio Awaga, Ryusuke Kondo, Seiichi Kagoshima

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   78 ( 12 )   2009年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PHYSICAL SOC JAPAN  

    We investigated the effects of hydrostatic pressure and uniaxial strain on the spin-Peierls (SP) transition of an organic radical magnet, benzo[1,2-d:4,5-d']bis[1,3,2]dithiazole(BBDTA)center dot InCl4. It has a one-dimensional coordination polymer structure along its c-axis and its SP transition occurs at 108 K. The SP transition temperature T-SP decreased to 99K at a hydrostatic pressure of 10 kbar, while it increased to 132 K at a uniaxial strain along the c-axis of 8 kbar. The pressure dependences of T-SP under these two conditions were discussed by evaluatingg two parameters, namely, the intrachain interaction 2J/k(B) and the effective spin-lattice coupling parameter eta, that are related to T-SP by the equation T-SP = 1.6 eta J/k(B). Under ambient pressure, the a- and c-axes of this material shortened monotonically with decreasing temperature, while the b-axis elongated below T-SP. In this study, we found the correlation between eta and the change in the lattice constant b. 2J/k(B) increased with increasing hydrostatic pressure and uniaxial strain, suggesting that the contraction along the c-axis does not depend on the manner of pressurization. From the evaluation of eta, the observed variation in T-SP is explained by the difference between the changes in b under the two pressurization conditions.

    DOI: 10.1143/JPSJ.78.124705

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  • Observation of ultrafast photoinduced closing and recovery of the spin-density-wave gap in (TMTSF)(2)PF6 査読

    Shinichi Watanabe, Ryusuke Kondo, Seiichi Kagoshima, Ryo Shimano

    PHYSICAL REVIEW B   80 ( 22 )   2009年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER PHYSICAL SOC  

    Photoexcited dynamics of a spin-density-wave (SDW) state in an organic linear-chain compound bis-(tetramethyl-tetraselenafulvalene)hexafluorophosphate, (TMTSF)(2)PF6, is investigated by optical pump and terahertz probe experiments. After the ultrashort laser-pulse excitation, a sudden closing followed by a recovery of the SDW gap is clearly observed in the far-infrared spectrum. The recovery time is found to diverge toward the phase-transition temperature, T-SDW, while the gap remains open at T-SDW. The observed critical slowing down behavior is interpreted in terms of three-dimensional fluctuation which enlarges near the phase-transition temperature.

    DOI: 10.1103/PhysRevB.80.220408

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  • Crystal and Electronic Structures of the Quasi-Two-Dimensional Organic Conductor alpha-(BEDT-TTF)(2)I-3 and Its Selenium Analogue alpha-(BEDT-TSeF)(2)I-3 under Hydrostatic Pressure at Room Temperature 査読

    Ryusuke Kondo, Seiichi Kagoshima, Naoya Tajima, Reizo Kato

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   78 ( 11 )   2009年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PHYSICAL SOC JAPAN  

    We perform crystal structure analyses of the organic conductor alpha-(BEDT-TTF)(2)I-3 [where BEDT-TTF denotes bis(ethylene)dithiotetrathiafulvalene] and its selenium analogue alpha-(BEDT-TSeF)(2)I-3 [where BEDT-TSeF denotes bis(ethylene)dithiotetraselenafulvalene] at room temperature under hydrostatic pressure, where they are expected to have zero-gap points at the Fermi level with a Dirac-cone-type dispersion for a massless particle. We calculate the electronic band structures using a combination of the extended Huckel molecular orbital calculation based on the obtained crystal structures and the tight-binding band structure calculation. We find that I) the obtained Fermi surfaces of both salts under hydrostatic pressure are simply larger than those at ambient pressure owing to an increase in overlap integrals caused by the pressure, and II) electronic structures having zero-gap points with a Dirac-cone-type dispersion at the Fermi level are realized only in alpha-(BEDT-TTF)(2)I-3 by the introduction of suitable site potentials in wide parameter areas. These results suggest that, to realize such a unique electronic structure in this class of materials, some mechanisms are needed to effectively give the site potentials employed in this study. Examples are electronic correlation effects and I-3 anion potentials.

    DOI: 10.1143/JPSJ.78.114714

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  • Spin-density-wave gap in (TMTSF)(2)PF6 probed by reflection-type terahertz time-domain spectroscopy 査読

    Shinichi Watanabe, Ryusuke Kondo, Seiichi Kagoshima, Ryo Shimano

    PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS   245 ( 12 )   2688 - 2691   2008年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:WILEY-BLACKWELL  

    We report on a development of the reflection-type terahertz time-domain spectroscopy system and apply it to determine the conductivity spectra of the spin density wave (SDW) ground states in (TMTSF)(2)PF6. We take special care over optimizing the spatial resolution of the measurement system in order to investigate the tiny sample and also for correcting the phase error of the measurement. We observe a distinct reduction of the optical conductivity below similar to 65 cm(-1), which is a clear indication of SDW gap formation with metal-insulator transition. (c) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

    DOI: 10.1002/pssb.200879900

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  • Hump like resistance anomaly in organic conductor β"-(BEDT-TTF)(2)CsCd(SCN)(4) 査読

    Kondo Ryusuke, Otsuji Jun, Kagoshima Seiichi, Nogami Yoshio

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   77 ( 6 )   2008年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1143/JPSJ.77.063702

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  • Charge ordered metal and pressure-induced superconductivity in the two-dimensional organic conductor beta-(DODHT)(2)PF(6) 査読

    Akito Kobayashi, Yoshikazu Suzumura, Momoka Higa, Ryusuke Kondo, Seiichi Kagoshima, Hiroyuki Nishikawa

    JOURNAL OF PHYSICS-CONDENSED MATTER   20 ( 12 )   2008年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IOP PUBLISHING LTD  

    The superconductivity in a quasi-two-dimensional organic conductor, beta"-(DODHT)(2)PF(6) salt, which is expected to appear after the melting of a charge ordering (CO) state, has been examined using an extended Hubbard model with anisotropy for both the transfer energies and the nearest-neighbor repulsive interactions between the DODHT molecules. The fluctuation is treated by the random phase approximation based on mean-field calculation of the CO. When pressure is applied, an insulating state with CO (COI) changes into a metallic state with weakened CO (COM) at an intermediate pressure, and a normal state without CO emerges at higher pressures. For the COM state at intermediate pressure, the COI state and the normal state also exist as metastable states, and their free energies are nearly the same within a narrow energy range of 10(-3) eV. Thus these three states may coexist with each other by forming a phase separation at finite temperature. We find that the spin fluctuation around such a mean-field COM state gives rise to a superconducting state with a full gap. Further, we suggest that d-wave superconductivity mediated by the charge fluctuation occurs in the normal state with a quasi-one-dimensional Fermi surface when the nearest-neighbor interaction becomes as large as the on-site interaction.

    DOI: 10.1088/0953-8984/20/12/125205

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  • Development of uniaxial elongation method and its application to low dimensional conductors 査読

    Hiroki Kowada, Ryusuke Kondo, Seiichi Kagoshima

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   76 ( 11 )   2007年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PHYSICAL SOC JAPAN  

    We developed the uniaxial elongation method to elongate a soft crystalline sample along one desired direction. An epoxy rod which contains a sample passes through a stainless steel ring along its diameter and is fixed to the ring. The external force is applied to the ring along the direction perpendicular to the epoxy rod to deform the ring and elongate the epoxy rod, leading to the elongation of the sample in the rod. We verify this method by using a strain gauge instead of a sample. The results of resistance measurements of two kinds of quasi-one-dimensional conductors, NbSe3 and (TMTSF)(2)ClO4(TMTSF denotes tetramethyltetraselenafulvalene.), are also presented as the examples of this experimental technique.

    DOI: 10.1143/JPSJ.76.114710

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  • Structural studies of pressure-induced organic superconductor beta ''-(DODHT)(2)PF6 having charge-ordering phase at ambient pressure 査読

    Momoka Higa, Ryusuke Kondo, Seiichi Kagoshima, Hiroyuki Nshikawa

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   76 ( 3 )   2007年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PHYSICAL SOC JAPAN  

    We performed the crystal structure analyses of the pressure-induced organic superconductor ss"-(DODHT)(2)PF6 (DODHT denotes (1,4-dioxane-2,3-diyldithio)dihydrotetrathiafulvalene) at the hydrostatic pressures of 0.75GPa and 1.9GPa in order to investigate the key parameter for inducing the superconductivity. At ambient pressure, ss"-(DODHT)(2)PF6 undergoes an insulator-to-insulator transition at 255 K accompanied by charge ordering. By applying pressure, this charge-ordering transition is suppressed and superconductivity is generated at around 3 K above 1.32 GPa. Using the obtained atomic coordinates, we estimated the transfer integrals t and intermolecular nearest-neighbor Coulomb interaction energies V between conduction electrons and found that one of V/vertical bar t vertical bar ratios perpendicular to charge-ordering stripes plays an important role in suppressing the charge-ordering phase.

    DOI: 10.1143/JPSJ.76.034709

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  • A possible internal deformation of the charge ordering and its meta-stability in the organic conductor theta-(BEDT-TTF)(2)CsZn(SCN)(4) 査読

    Ryusuke Kondo, Mornoka Higa, Seiichi Kagoshima

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   76 ( 3 )   2007年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PHYSICAL SOC JAPAN  

    Non-ohmic transport was studied by pulse method in the charge-ordered state of the organic conductor theta-(BEDT-TTF)(2)CsZn(SCN)(4) as controlling the electronic state by uniaxial strain method. It was discovered that the non-ohmic conduction under high electric fields lead to the meta-stable state with a structural modification, where the ohmic resistance was reduced to be smaller than the original. The response of the CO state to pulsed electric fields suggested a possible internal deformation of the ordered charge's lattice.

    DOI: 10.1143/JPSJ.76.033703

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  • Anisotropic superconducting transition in beta ''-(DODHT)(2)PF6 査読

    Momoka Higa, Ryusuke Kondo, Seiichi Kagoshima, Hiroyuki Nishikawa

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   76   186 - 187   2007年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PHYSICAL SOC JAPAN  

    We report unique resistance behavior around the superconducting transition of a quasi-two-dimensional organic superconductor, beta '''-(DODHT)(2)PF6 [DODHT = (1,4-dioxane-2,3-diyldithio)dihydrotetrathiafulvalene]. When the superconductivity appears, the interlayer resistance begins to decrease at a temperature higher than that for the intralayer resistance. Both resistances show a step-like decrease toward zero resistance. These unique phenomena are possibly related to the unique structural properties of the salt.

    DOI: 10.1143/JPSJS.76SA.186

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  • Ultrahigh-pressure effects in metallo-organics 査読

    Seiichi Kagoshima, Ryusuke Kondo, Nobuyuki Matsushita, Momoka Higa, Sergey V. Ovsyannikov, Nadezhda A. Shaydarova, Vladimir V. Shchennikov, Andrey Y. Manakov, Anna Y. Likhacheva

    PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS   244 ( 1 )   418 - 423   2007年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:WILEY-V C H VERLAG GMBH  

    The results are reported of the pressure (P) dependence of the electrical resistance (R), the thermoelectric power (Seebeck effect) (S), and compressibility as well as the time dependence of R at fixed P up to 20 GPa for four metallo-organics based on the BEDT-TTF (bisethylenedithiolo-tetrathiofulvalene) group, theta-(BEDT-TTF)(2)CsZn(SCN)(4), alpha-(BEDT-TTF)(2)I-3, beta'-(BEDT-TTF)(2)PF6, and (BEDT-TTF)-TCNQ. X-ray powder and single-crystal diffraction studies were also made on theta-(BEDT-TTF)(2)CsZn(SCN)(4) at high pressures up to P similar to 10 GPa. The R values of all the crystals decreased with pressure up to P similar to 3-5 GPa (low-pressure regime), and then the sign of dR/dP inverted (high-pressure regime). From the investigation of the mechanical and structural properties, these materials were found to have a large compressibility in the low-pressure regime, and a small one in the high-pressure region. In theta-(BEDT-TTF)(2)CsZn(SCN)(4) we observed pressure-induced reversible degradation (amorphization) in structure without a solid-phase reaction. (C) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

    DOI: 10.1002/pssb.200672530

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  • High-pressure research in organic conductors 査読

    Keizo Murata, Seiichi Kagoshima, Syuma Yasuzuka, Harukazu Yoshino, Ryusuke Kondo

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   75 ( 5 )   2006年5月

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    記述言語:英語   出版者・発行元:PHYSICAL SOC JAPAN  

    High-pressure studies on organic conductors and superconductors are reviewed. It is stressed that almost all the organic conductors are studied by means of high pressures, but the role or meaning of pressure effect has been dependent on the salts and physics of interests. In organic molecular crystals, many intriguing physical phenomena such as the appearance of charge- and spin-density-waves, superconductivity, Mott insulator and charge ordering have been found. The application of hydrostatic and uniaxial pressures plays an essential role for understanding the nature of these electronic states, for guiding the material design, and for creating the unexpected quantum states as well as high-T-c superconductivities. This review includes the history, pressure techniques, and works under conventional pressures of up to 1.5 GPa, ultra-high pressures up to 10 GPa as well as uniaxial pressure, but the topics which are dealt with in this same special issue are not covered.

    DOI: 10.1143/JPSJ.75.051015

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  • A one-dimensional coordination polymer, BBDTA center dot InCl4: Possible spin-Peierls transition with high critical temperature of 108 K 査読

    Wataru Fujita, Kunio Awaga, Ryusuke Kondo, Seiichi Kagoshima

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   128 ( 18 )   6016 - 6017   2006年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER CHEMICAL SOC  

    DOI: 10.1021/ja060979+

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  • Electrical and Structural Properties of θ-type BEDT-TTF Organic Conductors under Uniaxial Strain

    R. Kondo, M. Higa, S. Kagoshima, H. Hoshino, T. Mori, H. Mori

    Journal of the Physical Society of Japan   75 ( 4 )   044716   2006年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1143/JPSJ.75.044716

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  • Superconducting and charge ordering phases of two-dimensional organic conductors 査読

    R. Kondo, M. Higa, S. Kagoshima

    JOURNAL OF LOW TEMPERATURE PHYSICS   142 ( 3-4 )   535 - 538   2006年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER/PLENUM PUBLISHERS  

    In order to investigate relationships between superconducting phase and charge ordered one, the uniaxial strain method is applied to the superconducting salt alpha-(BEDT-TTF)(2)NH4Hg(SCN)(4) and the organic conductor alpha-(BEDT-TTF)(2)CSCd(SCN)(4). Both salts preserve metallic states under a-axial strain and show insulating behaviours under c-axial strain. These results suggest that i) c-axial strain controls the electronic properties of the a-type salts, and ii) the insulating state in the vicinity of the superconducting phase of alpha-(BEDT-TTF)(2)NH4Hg(SCN)(4) is a charge ordered phase, as expected from the comparison in the lattice parameters with the charge ordered salt theta-(BEDT-TTF)(2)RbZn(SCN)(4).

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  • Magnetic correlation in BETS2(Cl(2)TCNQ) 査読

    Y. Takano, K. Hiraki, T. Takahashi, R. Kondo, S. Kagoshima, T. Hasegawa, T. Mocihda, Y. Iwasa

    JOURNAL OF LOW TEMPERATURE PHYSICS   142 ( 3-4 )   647 - 650   2006年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER/PLENUM PUBLISHERS  

    We carried out Se-77 NMR measurements on BETS2(Cl(2)TCNQ) under pressure in order to investigate the magnetic properties of the insulating state which appears above 0.6 GPa. The relaxation rate 1/T-1 at 0.7 GPa shows small peak-like anomaly at 20 K, indicating a spin density wave transition as observed in BETS2(Br(2)TCNQ).

    DOI: 10.1007/s10909-006-9201-0

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  • Structural and electronic properties of a new molecular conductor, alpha-(BEDT-TTF)(2)CsCd(SCN)(4) 査読

    R Kondo, M Higa, S Kagoshima

    SOLID STATE COMMUNICATIONS   137 ( 12 )   637 - 640   2006年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Structural and electronic properties of a new BEDT-TTF based radical cation salt, alpha-(BEDT-TTF)(2)CsCd(SCN)(4), are presented. In the measurements of the electrical resistivity and the magnetic susceptibility, this new a-type salt shows metallic behavior down to low temperature. Measurements of the resistivity under in-plane c-axial strain reveal a newly observed insulating phase, suggesting that alpha-(BEDT-TTF)(2)CsCd(SCN)(4) is placed near an insulating phase which might have close relationships with a superconducting phase realized in a-type salts. (c) 2006 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.ssc.2006.01.025

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  • Magneto-transport properties in the density wave phase of beta ''-(BEDT-TTF)(2)CsCd(SCN)(4) 査読

    R. Kondo, J. Otsuji, S. Kagoshima

    YAMADA CONFERENCE LX ON RESEARCH IN HIGH MAGNETIC FIELDS   51   327 - +   2006年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IOP PUBLISHING LTD  

    Magneto-transpon properties of the newly prepared layer-structured organic conductor beta"-(BEDT-TTF)(2)CsCd(SCN)(4) are investigated. Temperature dependence of the interlayer resistance without magnetic fields shows a hump-like anomaly between 32 K and 5 K at ambient pressure. Measurements of the Shubnikov-de Haas oscillations indicate that the electronic structure at low temperature is different from that calculated from the crystal structure at room temperature. Under magnetic fields parallel to the layer, magnetic field dependence of the interlayer resistance also shows a large dip-like anomaly below 32 K, where the hump-like anomaly starts to appear. We suggest that the hump-like anomaly of beta"-(BEDT-TTF)(2)CsCd(SCN)(4) is a density wave transition accompanied by nesting of its one dimensional Fermi surfaces, and that the dip-like anomaly in the magneto-resistance is ascribed to magnetic field dependence of the interlayer hopping of electrons.

    DOI: 10.1088/1742-6596/51/1/076

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  • Crystal structure analysis under uniaxial strain at low temperature using a unique design of four-axis x-ray diffractometer with a fixed sample

    R Kondo, S Kagoshima, J Harada

    REVIEW OF SCIENTIFIC INSTRUMENTS   76 ( 9 )   093902   2005年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER INST PHYSICS  

    For the purpose of crystal structure analysis under uniaxial strain at low temperatures, we developed a pressure cell for uniaxial compression and a unique design of an x-ray diffractometer wherein both the x-ray source and the detector are capable of two-axial rotation with a fixed sample. This arrangement is advantageous to crystal structure analyses under extreme conditions that require a large and heavy apparatus. Using the present diffractometer, we performed the crystal structure analyses of the organic conductor, alpha-(BEDT-TTF)(2)I-3 (BEDT-TTF denotes bis(ethylene)dithio-tetrathiafulvalene), under uniaxial strain and ambient pressure, and at room and low temperatures, and obtained results that were qualitatively consistent with those of resistivity measurements. (c) 2005 American Institute of Physics.

    DOI: 10.1063/1.2001607

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  • Molecular arrangement and electronic band structure of theta-(BEDT-TTF)(2)CsZn(SCN)(4) controlled by uniaxial compression 査読

    R Kondo, M Higa, S Kagoshima, H Hoshino, T Mori, H Mori

    CURRENT APPLIED PHYSICS   4 ( 5 )   484 - 487   2004年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    Using the uniaxial strain method, the lattice parameters and the atomic positions of the quasi-two-dimensional organic conductor theta-(BEDT-TTF)(2)CsZn(SCN)(4) were measured at room temperature with piston pressures up to 10 kbar applied parallel to the c-axis in the conducting plane. The lattice parameter c was predominantly reduced with increasing the piston pressure although a small Poisson's effect occurred in the parameter a. Band calculation showed that the transfer integrals under the uniaxial compression by the piston pressure of 10 kbar became similar to those of theta-(BEDT-TTF)(2) RbZn(SCN)(4). This result is consistent with that of transport measurements reported already and suggests that a charge disproportionation, which has been observed in the RbZn-compound, occurs also in the present compound under the uniaxial compressive strain. (C) 2004 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.cap.2004.01.004

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  • Phase transition on (BEDO-TTF) (Cl(2)TCNQ): Spin dynamics observed by NMR measurements 査読

    M Takahashi, K Hiraki, T Takahashi, T Hasegawa, R Kondo, S Kagoshima

    JOURNAL DE PHYSIQUE IV   114   141 - 142   2004年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:E D P SCIENCES  

    C-13 NMR measurements were carried out to investigate the electronic state of Mixed-stack organic charge-transfer complex (BEDO-TTF)(Cl(2)TCNQ). From the remarkable temperature dependence of the central shift and relaxation rate, we have confirmed that the transition at 110 K is from paramagnetic to nonmagnetic spin-singlet phase.

    DOI: 10.1051/jp4:2004114033

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  • Crystal and electronic structures of alpha-(BEDT-TTF)(2)I-3 under uniaxial strains 査読

    R Kondo, S Kagoshima

    JOURNAL DE PHYSIQUE IV   114   523 - 525   2004年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:E D P SCIENCES  

    In order to investigate relationships between the crystal structure and electronic properties, crystal structure analyses of alpha-(BEDT-TTF)(2)I-3 were performed under in-plane uniaxial strains. It is known that, at ambient pressure, this salt has a semimetallic electronic structure having hole and electronic pockets, and undergoes a metal-insulator transition at 135 K due to a charge disproportionation on BEDT-TTF molecules. Present structure analyses showed that the sizes of both hole and electron like pockets on the Fermi surface rather decreased under a-axial strain, while those of hole ones increased under b-axial strain. These results are qualitatively consistent with observed behaviors of the metal-insulator transition under uniaxial strains.

    DOI: 10.1051/jp4:2004114123

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  • Band structure control of organic superconductors by the uniaxial strain method 査読

    S. Kagoshima, R. Kondo, M. Maesato

    Synthetic Metals   137 ( 1-3 )   1163 - 1165   2003年

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  • Uniaxial strain study of electronic and crystal structures of organic conductors 査読

    S. Kagoshima, R. Kondo, M. Chusho, M. Maesato, T. Mori, H. Mori, S. Tanaka

    Synthetic Metals   133-134   145 - 146   2003年

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  • Crystal and band structures of organic superconductor under the uniaxial strain 査読

    R. Kondo, S. Kagoshima, M. Maesato

    Physica C: Superconductivity and its Applications   388-389   601 - 602   2003年

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    記述言語:英語  

    DOI: 10.1016/S0921-4534(02)02760-0

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  • Crystal structure of organic superconductor, α-(BEDT-TTF)2NH4Hg(SCN)4, under the uniaxial strain 査読

    R. Kondo, S. Kagoshima, M. Maesato

    Synthetic Metals   133-134   137 - 139   2003年

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    記述言語:英語  

    DOI: 10.1016/S0379-6779(02)00336-3

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  • Control of electronic properties of organic superconductors by uniaxial strain method 査読

    S. Kagoshima, R. Kondo, T. Shibata, H. Hirai, M. Maesato, H. Hoshino, T. Mori, H. Mori, S. Tanaka

    Molecular Crystals and Liquid Crystals Science and Technology Section A: Molecular Crystals and Liquid Crystals   380   77 - 84   2002年

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    記述言語:英語  

    DOI: 10.1080/10587250290101397

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  • Effects of uniaxial strain on α-(BEDT-TTF)2MHg(SCN) 4 [M=K, NH4] 査読

    M. Maesato, S. Kagoshima, R. Kondo, T. Shibata, H. Hirai

    Molecular Crystals and Liquid Crystals Science and Technology Section A: Molecular Crystals and Liquid Crystals   376   195 - 200   2002年

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    記述言語:英語  

    DOI: 10.1080/10587250210805

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  • Superconductivity and metal-insulator transition in twin-columnar organic superconductor, (BETS)(2)(X(2)TCNQ) [X=Cl, Br]

    R Kondo, T Hasegawa, T Mochida, S Kagoshima, Y Iwasa, K Hiraki, T Takahashi

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   70 ( 10 )   3023 - 3030   2001年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PHYSICAL SOC JAPAN  

    Low-temperature electronic properties of the first all-organic donor-acceptor-type superconducting system, (BETS)(2)(X(2)TCNQ) [X=Cl, Br] under high pressure have been investigated by means of resistivity and H-1 NMR experiments. The crystal structure of this class of complexes is characterized by a twin-columnar structure of BETS without intra-columnar dimerization at room temperature. Pressure-temperature phase diagrams are established for these compounds, where the electronic ground status are spin-density-wave (SDW's) insulators, except a narrow, region of superconducting state in (BETS)(2)(Cl(2)TCNQ). A possible unified picture of the electronic states of the title compounds is discussed in terms of hydrostatic pressure effects and chemical substitution ones on them.

    DOI: 10.1143/JPSJ.70.3023

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  • Neutral-ionic phase transition of (BEDT-TTF)(ClMeTCNQ) under pressure 査読

    T Hasegawa, T Akutagawa, T Nakamura, T Mochida, R Kondo, S Kagoshima, Y Iwasa

    PHYSICAL REVIEW B   64 ( 8 )   2001年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER PHYSICAL SOC  

    Observation and characterization are reported on a neutral-ionic (NI) phase transition under pressure in (BEDT-TTF)(ClMeTCNQ), which is a mixed-stack charge-transfer compound with BEDT-TTF-based intercolumnar networks. Optical and electrical experiments revealed that the compound undergoes a pressure-induced NI transition at 1 GPa at room temperature. The temperature-pressure phase diagram of this phase transition was established by the electrical resistivity measurements at low temperature under pressure. The observed symmetry breaking in the infrared spectra and dramatic decrease of resistivity indicate that the NI transition in (BEDT-TTF)(ClMeTCNQ) at 1 GPa at room temperature is qualitatively similar in nature to that in the standard material (TTF)(CA). In contrast, the NI transition in (BEDT-TTF)(ClMeTCNQ) at low temperature under lower pressure considerably differs from that in (TTF)(CA) as to the resistivity behaviors around the phase boundary: The former becomes almost continuous without showing any anomaly, while the latter is significantly discontinuous. We discuss the origin of the observed electrical behaviors in (BEDT-TTF)(ClMeTCNQ) in terms of the effect of intercolumnar interaction associated with BEDT-TTF moieties.

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  • Electronic states of novel donor/acceptor type of organic superconductor, (BETS)(2)(Cl(2)TCNQ) 査読

    K Hiraki, T Takahashi, R Kondo, S Kagoshima, T Hasegawa, T Mochida, Y Iwasa

    JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS   62 ( 1-2 )   401 - 403   2001年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    H-1 and Se-77 NMR measurements have been performed to clarify the electronic properties of charge transfer complexes, (BETS)(2)(X(2)TCNQ) (X = Cl and Br). In the CI,TCNQ complex, a Korringa-like relaxation behavior has been observed in the metallic state at ambient pressure. At 6.5 kbar, where a metal-insulator (M-I) transition is induced, a sign of anitiferromagnetic ordering was observed in the insulating state at 10 K. In the Br(2)TCNQ complex, we have also found that Se-77-1/T-1 forms a peak around the M-I transition temperature and that NMR line is broadened in the insulating state. The nature of the insulating states of both compounds seem to be the same, (C) 2000 Elsevier Science Ltd. All rights reserved.

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  • Novel electronic states of organic conductors under uniaxial stress or uniaxial strain 査読

    S. Kagoshima, M. Maesato, Y. Kaga, R. Kondo

    Synthetic Metals   117 ( 1-3 )   87 - 90   2001年

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    記述言語:英語  

    DOI: 10.1016/S0379-6779(00)00543-9

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  • Donor-acceptor-type complexes of (BEDT-TTF)(TCNQ) analogues: Peculiar magnetic transition in (BEDO-TTF)(Cl2TCNQ) 査読

    T. Hasegawa, R Kondo, S. Kagoshima, Y. Iwasa, T. Mochida, T. Akutagawa, T. Nakamura

    Synthetic Metals   120   991 - 992   2001年

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    記述言語:英語  

    DOI: 10.1016/S0379-6779(00)00897-3

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  • Control of electronic properties of (formula presented) (formula presented) by the uniaxial strain method 査読

    M. Maesato, Y. Kaga, R. Kondo, S. Kagoshima

    Physical Review B - Condensed Matter and Materials Physics   64 ( 15 )   2001年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Systematic uniaxial strain studies of (formula presented) (formula presented) have been carried out. By controlling the in-plane lattice parameters a and c independently, we find that both compounds have essentially the same phase diagram in electronic properties, although, under the hydrostatic pressures, they show quite different phase diagrams. The K salt shows the superconductivity like (formula presented) salt under the c-axis uniaxial strain, and the latter undergoes a transition to the density-wave state like the former under the a-axis uniaxial strain. These changes in electronic structures are verified by measuring the angle-dependent magnetoresistance. The electronic properties of these compounds can be systematically understood as a function of (formula presented) the ratio of the in-plane lattice parameters. © 2001 The American Physical Society.

    DOI: 10.1103/PhysRevB.64.155104

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  • Control of electronic properties of α-(BEDT-TTF)2MHg(SCN)4 (M = K, NH4) by the uniaxial strain method 査読

    M. Maesato, Y. Kaga, R. Kondo, S. Kagoshima

    Physical Review B - Condensed Matter and Materials Physics   64 ( 15 )   1551041 - 1551048   2001年

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    DOI: 10.1103/PhysRevB.64.155104

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  • Artificial control of intermolecular distance of organic superconductors: α -type BEDT-TTF compounds 査読

    S. Kagoshima, T. Shibata, H. Hirai, R. Kondo, M. Maesato

    Current Applied Physics   1 ( 1 )   72 - 76   2001年

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    記述言語:英語  

    DOI: 10.1016/S1567-1739(00)00014-6

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  • Electronic and crystal structures of organic superconductors under the uniaxial strain 査読

    S. Kagoshima, R. Kondo, M. Maesato

    Current Applied Physics   1 ( 4-5 )   307 - 311   2001年

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    記述言語:英語  

    DOI: 10.1016/S1567-1739(01)00029-3

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  • Uniaxial strain study of organic conductors (TMTSF)2PF6 査読

    H. Hirai, R. Kondo, M. Maesato, T. Shibata, S. Kagoshima

    Synthetic Metals   120 ( 1-3 )   963 - 964   2001年

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    記述言語:英語  

    DOI: 10.1016/S0379-6779(00)00691-3

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  • Uniaxial strain study of organic conductors α-(BEDT-TTF)2MHg(SCN)4 [M=K, NH4] 査読

    M. Maesato, Y. Kaga, R. Kondo, H. Hirai, S. Kagoshima

    Synthetic Metals   120 ( 1-3 )   941 - 942   2001年

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    記述言語:英語  

    DOI: 10.1016/S0379-6779(00)01178-4

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  • Control of electronic properties of organic conductors by uniaxial strain method 査読

    S. Kagoshima, M. Maesato, R. Kondo, T. Shibata, H. Hirai

    Synthetic Metals   120 ( 1-3 )   683 - 686   2001年

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  • Control of electronic properties of organic conductors by hydrostatic and uniaxial compression 査読

    S. Kagoshima, R. Kondo, H. Hirai, T. Shibata, Y. Kaga, M. Maesato

    Physica Status Solidi (B) Basic Research   223 ( 1 )   97 - 104   2001年

  • Electronic states in the spin-density wave phase of organic conductors: Roles of the coexisting 2kF and 4kF charge-density waves 査読

    S. Kagoshima, Y. Saso, M. Maesato, R. Kondo, T. Yamaguchi, V.A. Bondarenko, T. Hasegawa

    Synthetic Metals   117 ( 1-3 )   39 - 43   2001年

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    記述言語:英語  

    DOI: 10.1016/S0379-6779(00)00536-1

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  • Mixed-stack organic charge-transfer complexes with intercolumnar networks 査読

    T Hasegawa, T Mochida, R Kondo, S Kagoshima, Y Iwasa, T Akutagawa, T Nakamura, G Saito

    PHYSICAL REVIEW B   62 ( 15 )   10059 - 10066   2000年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER PHYSICAL SOC  

    We report synthesis and examination of the electronic properties of an isomorphous series of mixed-stack organic charge-transfer complexes, composed of [bis(ethylenedithio) tetrathiafulvalene] (BEDT-TTF)-based electron donors and electron accepters of halogen-substituted tetracyanoquinodimethanes (TCNQ's). Single crystals of (BEDT-TTF)(Me,TCNQ), (BEDT-TTF)(CIMeTCNQ), and (BEDO-TTF)(Cl(2)TCNQ) were investigated as to their crystal structures, and optical and magnetic properties. The intermolecular overlaps between the stacked columns were comparable to the face-to-face overlap between the donor and the acceptor molecules inside the stacks. As seen from the optical and magnetic measurements, the (BEDT-TTF)(Me,TCNQ) and (BEDT-TTF)(ClMeTCNQ) complexes were neutral, while the (BEDO-TTF)(Cl(2)TCNQ), complex was found to be ionic. Among these complexes, anomalous magnetic properties were observed in the ionic complex of (BEDO-TTF)(Cl(2)TCNQ). (BEDO-TTF)(CI,TCNQ) is a magnetic insulator with Curie-Weiss behavior in magnetic susceptibility followed by a sharp drop at around 120 K, which is in sharp contrast to conventional "spin-Peierls-type'' nonmagnetic mixed-stack ionic compounds.

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  • Uniaxial strain method for soft crystals: Application to the control of the electronic properties of organic conductors

    M Maesato, Y Kaga, R Kondo, S Kagoshima

    REVIEW OF SCIENTIFIC INSTRUMENTS   71 ( 1 )   176 - 181   2000年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER INST PHYSICS  

    We developed the uniaxial strain method to compress a crystalline sample along any direction without involving Poisson's effect. The uniaxial strain is realized by inserting a composite of either the sample embedded in epoxy or the sample in frozen oil into a cylinder much harder than the sample composite followed by the application of external forces to a piston put on the sample composite. We verified, by using a strain gauge embedded in the epoxy or the frozen oil, that the strain thus created has the uniaxial nature. Resistance measurements on two kinds of organic conductors, alpha-(BEDT-TTF)(2)KHg(SCN)(4) and alpha-(BEDT-TTF)(2)I-3 under the uniaxial strain showed novel electric properties that have never been found under hydrostatic pressures. Their properties were found to be largely dominated by the direction of the uniaxial strain even when it is applied along directions in the conducting plane having a two-dimensional nature. (C) 2000 American Institute of Physics. [S0034-6748(00)05001-2].

    DOI: 10.1063/1.1150180

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  • Semiclassical and non-classical angular effects of magnetoresistance in (TMTSF)2X 査読

    Toshihito Osada, Toshihito Osada, Nobuharu Kami, Nobuharu Kami, Ryusuke Kondo, Seiichi Kagoshima

    Synthetic Metals   103   2024 - 2027   1999年6月

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    We have studied the semiclassical and non-semiclassical behaviors of magnetoresistance (MR) in a quasi-one-dimensional (Q1D) conductor (TMTSF)2ClO4. Based on the Boltzmann equation, we numerically investigated possible semiclassical 'angular effects', the characteristic patterns of the field-orientation-dependence of MR, in the general Q1D conductors. Particularly, we have clarified the complicated situation around B//1D-axis in which different angular effects are mixed up. The angular dependent MR features in the metallic phase of (TMTSF)2ClO4almost obey the semiclassical theory except a dip structure around B//b'. As for this non-semiclassical feature, we discuss the possibility of the one-body and many-body field-induced electron confinement onto a single conducting layer.

    DOI: 10.1016/S0379-6779(98)00289-6

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  • Organic metals involving double chain donor arrangements, (BMDT-TTF)(2)((RR2)-R-1-TCNQ) [R-1 = H, Me, R-2 = Cl, Br] 査読

    T Mochida, T Hasegawa, R Kondo, S Kagoshima, Y Iwasa

    SYNTHETIC METALS   102 ( 1-3 )   1680 - 1680   1999年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE SA  

    The title compounds show unique crystal structures involving double-column donor arrangements, affording characteristic fourfold Fermi surfaces. They show metallic conductivities, accompanied by metal-insulator transitions at low temperatures.

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  • Electronic phase transition of BEDT-TTF based mixed-stack charge-transfer complexes 査読

    T Hasegawa, T Akutagawa, T Nakamura, Y Sasou, R Kondo, S Kagoshima, T Mochida, G Saito, Y Iwasa

    SYNTHETIC METALS   103 ( 1-3 )   1804 - 1805   1999年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE SA  

    The BEDT-TTF based mixed-stack charge-transfer (CT) complexes have been investigated for a series of isostructural compounds. The ionic complex of (BEDO-TTF)(Cl(2)TCNQ) is a magnetic insulator with showing Curie-Weiss behavior in magnetic susceptibility, in sharp contrast to the conventional mixed-stack CT complexes. The (BEDT-TTF)(ClMeTCNQ) compound undergoes neutral-ionic (NI) phase transition at high pressure.

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  • Donor-acceptor type superconductor, (BETS)(2)(Cl(2)TCNQ)

    R Kondo, T Hasegawa, T Mochida, S Kagoshima, Y Iwasa

    CHEMISTRY LETTERS   1999 ( 4 )   333 - 334   1999年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:CHEMICAL SOC JAPAN  

    It was found that (BETS)(2)(Cl(2)TCNQ) is an all-organic superconductor, where BETS is bis(ethylenedithio)tetraselenafulvalene and Cl(2)TCNQ is 2,5-dichlorotetracyanoquinodimethane. The superconducting critical temperature was 1.3 K+/-0.3 K under pressure.

    DOI: 10.1246/cl.1999.333

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  • Low-temperature diffuse X-ray studies of charge-density waves coexisting with spin-density waves in the organic conductors (TMTSF)2PF6 and (TMTSF)2AsF6 査読

    S. Kagoshima, Y. Saso, M. Maesato, R. Kondo, T. Hasegawa

    Solid State Communications   110 ( 9 )   479 - 483   1999年

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    記述言語:英語  

    DOI: 10.1016/S0038-1098(99)00113-1

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  • Electrical properties of Zn-Mg-RE (RE=Y, Gd) icosahedral quasicrystals

    R Kondo, T Hashimoto, K Edagawa, S Takeuchi, T Takeuchi, U Mizutani

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   66 ( 4 )   1097 - 1102   1997年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PHYSICAL SOC JAPAN  

    The electrical resistivity and the magnetoresistance have been measured for icosahedral phases of Zn-Mg-RE (RE=Y, Gd). Electrical resistivities of bulk samples of Zn56Mg36Y8, annealed ribbon samples of Zn62Mg30Y8 and annealed ribbon samples of Zn55Mg35.5Gd9.5 are 1 m Ohm cm, 0.3 m Ohm cm and 0.3 m Ohm cm. respectively. The resistivities of all the samples decrease by 5 similar to 7% from 4.2 K to 273 K. At low temperatures, the conductivity of Zn-Mg-Y obeys T-1/2 dependence, while the resistivity of Zn-Mg-Gd obeys ln T dependence, where Gd atoms bear magnetic moments. In Zn-Mg-Y; the magnetoresistance is negative and insensitive to temperature, while in Zn-h Ig-Gd it is positive in a low field range and becomes negative at high field with its magnitude larger at lower temperature. These results are interpreted by the theories of electron-electron interaction, weak localization and s-d exchange interaction.

    DOI: 10.1143/JPSJ.66.1097

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MISC

  • 7pBJ-4 希土類化合物RNiC_2(R=Sm,Nd)のホール効果(7pBJ 希土類化合物(磁性,価数揺動,カイラリティ),領域8(強相関系))

    野村 勝史, 近藤 隆祐, 野上 由夫

    日本物理学会講演概要集   69 ( 2 )   341 - 341   2014年8月

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    記述言語:日本語   出版者・発行元:一般社団法人日本物理学会  

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  • 27aCJ-7 希土類化合物RNiC_2(R=Y,Ho,Er)の構造相転移(27aCJ 希土類化合物(磁性・重い電子状態・価数揺動など),領域8(強相関系))

    近藤 隆祐, 前田 浩之, 野村 勝史, 野上 由夫

    日本物理学会講演概要集   69 ( 1 )   550 - 550   2014年3月

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    記述言語:日本語   出版者・発行元:一般社団法人日本物理学会  

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  • 26aXZE-10 希土類化合物RNiC_2の単結晶作成と物性測定(26aXZE 希土類化合物,領域8(強相関系:高温超伝導,強相関f電子系など))

    前田 浩之, 山本 伸樹, 近藤 隆祐, 野上 由夫

    日本物理学会講演概要集   68 ( 1 )   578 - 578   2013年3月

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    記述言語:日本語   出版者・発行元:一般社団法人日本物理学会  

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  • 27pXN-5 (TMTTF)_2Brの低温構造(27pXN 擬一次元系,パイエルス転移,領域7(分子性固体・有機導体))

    戸田 敦基, 近藤 隆祐, 野上 由夫, 中尾 朗子, 熊井 玲児

    日本物理学会講演概要集   68 ( 1 )   939 - 939   2013年3月

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    記述言語:日本語   出版者・発行元:一般社団法人日本物理学会  

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  • 21aEA-2 超伝導体Cu_xBi_2Se_3の作成と他元素導入の試み(21aEA トポロジカル超伝導・マヨラナ粒子,領域4(半導体,メゾスコピック系・局在))

    近藤 隆祐, 吉中 泰輝, 今井 良宗, 前田 京剛

    日本物理学会講演概要集   67 ( 2 )   648 - 648   2012年8月

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    記述言語:日本語   出版者・発行元:一般社団法人日本物理学会  

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  • 24pBK-2 量子スピン液体κ-(BEDT-TTF)_2Cu_2(CN)_3の低温対称性変化の観測(24pBK スピン液体・モット転移・金属錯体,領域7(分子性固体・有機導体))

    山本 伸樹, 野上 由夫, 近藤 隆祐, 寺崎 一郎, 佐々木 孝彦, 前里 光彦, 花咲 徳亮, 中尾 朗子

    日本物理学会講演概要集   67 ( 1 )   876 - 876   2012年3月

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    記述言語:日本語   出版者・発行元:一般社団法人日本物理学会  

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  • 26pBK-2 θ-(BEDT-TTF)_2CsZn(SCN)_4の一軸圧縮下の変調波数変化と物性(26pBK 電荷秩序・非線形伝導,領域7(分子性固体・有機導体))

    野上 由夫, 谷本 由衣, 近藤 隆祐, 花咲 徳亮

    日本物理学会講演概要集   67 ( 1 )   907 - 907   2012年3月

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    記述言語:日本語   出版者・発行元:一般社団法人日本物理学会  

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  • 27aBK-4 新散漫散乱カメラによる(TMTSF)_2PF_6のSDW転移に先立つCDWゆらぎの観測(27aBK 擬一次元系,領域7(分子性固体・有機導体))

    戸田 敦基, 野上 由夫, 山本 伸樹, 近藤 隆祐, 花咲 徳亮

    日本物理学会講演概要集   67 ( 1 )   918 - 918   2012年3月

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    記述言語:日本語   出版者・発行元:一般社団法人日本物理学会  

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  • 27aYC-10 DyNiC_2およびCeNiC_2単結晶による電荷密度波の観測と磁気抵抗(27aYC 希土類化合物,領域8(強相関系:高温超伝導,強相関f電子系など))

    前田 浩之, 山本 伸樹, 野上 由夫, 近藤 隆祐, 花咲 徳亮, 下村 晋

    日本物理学会講演概要集   67 ( 1 )   685 - 685   2012年3月

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    記述言語:日本語   出版者・発行元:一般社団法人日本物理学会  

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  • Pd-Bi-Se単結晶の超伝導特性

    今井良宗, 鍋島冬樹, 吉中泰輝, 宮谷昂佑, 近藤隆祐, 小宮世紀, 塚田一郎, 前田京剛

    応用物理学会学術講演会講演予稿集(CD-ROM)   73rd   2012年

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  • Pd-Bi-Se単結晶の超伝導特性

    今井良宗, 鍋島冬樹, 吉中泰輝, 宮谷昂佑, 近藤隆祐, 小宮世紀, 塚田一郎, 前田京剛

    日本物理学会講演概要集   67 ( 2 )   2012年

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  • 一軸歪み法を用いた有機導体の電子制御 招待 査読

    近藤隆祐, 前里光彦

    固体物理   46 ( 5 )   2011年5月

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  • 25aTA-4 一軸性圧縮下θ-(BEDT-TTF)_2CsZn(SCN)_4の構造変調(25aTA 電荷秩序・非線形伝導,領域7(分子性固体・有機導体))

    近藤 隆祐, 鹿児島 誠一, 熊井 玲児, 中尾 朗子, 谷本 由衣, 野上 由夫, 澤 博

    日本物理学会講演概要集   66 ( 1-4 )   2011年3月

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    記述言語:日本語   出版者・発行元:社団法人日本物理学会  

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  • 一軸柱圧縮下θ‐(BEDT‐TTF)2CsZn(SCN)4の構造変調

    近藤隆祐, 鹿児島誠一, 熊井玲児, 中尾朗子, 谷本由衣, 野上由夫, 澤博

    日本物理学会講演概要集   66 ( 1 )   842   2011年3月

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    記述言語:日本語  

    J-GLOBAL

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  • スピンパイエルス物質における静水圧力・一軸性圧縮効果と自在な物性制御 招待 査読

    美藤正樹, 出口博之, 藤田 渉, 近藤隆祐, 鹿児島誠一

    固体物理   45 ( 7 )   2010年7月

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  • 23pRB-12 β"-(DODHT)_2PF_6の電荷秩序と超伝導(23pRB 超伝導・理論,領域7(分子性固体・有機導体))

    近藤 隆祐, 鹿児島 誠一, 山本 薫, 薬師 久弥, 西川 浩之

    日本物理学会講演概要集   65 ( 0 )   2010年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本物理学会  

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  • Control of electronic properties of molecular conductors by uniaxial strain

    S Kagoshima, R Kondo

    CHEMICAL REVIEWS   104 ( 11 )   5593 - 5608   2004年11月

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    記述言語:英語   掲載種別:書評論文,書評,文献紹介等   出版者・発行元:AMER CHEMICAL SOC  

    DOI: 10.1021/cr0306539

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  • 中性-イオン性転移系単結晶の低温・低温高圧構造解析

    熊井玲児, 堀内佐智雄, 高橋幸裕, 長谷川達生, 十倉好紀, 近藤隆祐, 鹿児島誠一, 沢博

    日本化学会講演予稿集   84th ( 1 )   30   2004年3月

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    記述言語:日本語  

    J-GLOBAL

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  • Uniaxial Strain Effect on the q-Phase Organic Conductor with a Large Dihedral Angle, θ-(TMET-TTP)4PF6

    T. Takeuchi, H. Hoshino, R. Kondo, S. Kagoshima, M, Enomoto T, Kawamoto, T. Mori

    J. Phys. Soc. Jpn.   72 ( 5 )   1152 - 1154   2003年

  • Metal-insulator transition of donor-acceptor-type organic charge-transfer complex (BETS)(2)(Br(2)TCNQ): Site-selective NMR measurements

    K Hiraki, S Furuta, T Takahashi, R Kondo, S Kagoshima, T Hasegawa, T Mochida, Y Iwasa

    PHYSICAL REVIEW B   66 ( 3 )   035104-1-035104-6   2002年7月

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    記述言語:英語   出版者・発行元:AMERICAN PHYSICAL SOC  

    The roles of donor layers and acceptor stacks in the electronic properties of the charge transfer complex, (BETS)(2)(Br(2)TCNQ) were investigated by means of site-selective NMR measurements. Line broadening of Se-77 NMR indicating a magnetic ordering on the BETS site was observed at the metal-insulator transition temperature 12 K. This transition is caused by the spin-density-wave formation on the BETS layers. C-13 NMR on the cyano carbon in the Br(2)TCNQ molecule confirms that a spin singlet formation starts to develop on the one dimensional Br(2)TCNQ columns below 170 K and its three dimensional ordering appears below 80 K. From the analysis of the NMR line shape and shift, magnetic susceptibility was decomposed into the contributions of the BETS and Br(2)TCNQ sites.

    DOI: 10.1103/PhysRevB.66.035104

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  • 24aXM-4 一軸性圧縮下における構造解析:α-(ET)_2NH_4HG(SCN)_4(24aXM ET錯体類(α系,θ系など),領域7(分子性固体・有機導体分野))

    近藤 隆祐, 麗児島 誠一, 前里 光彦

    日本物理学会講演概要集   57 ( 1 )   759 - 759   2002年3月

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    記述言語:日本語   出版者・発行元:一般社団法人日本物理学会  

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  • Structural Control of Organic Conductors by Uniaxial Strain: θ- and α-Phases of BEDT-TTF Compounds

    R. Kondo, S. Kagoshima, M. Chusho, H. Hoshino, T. Mori, H. Mori, S. Tanaka

    Current Appl. Phys.   2 ( 6 )   483 - 487   2002年

  • Electronic properties of novel donor-acceptor type charge transfer complexes, (BETS)(2)(X(2)TCNQ) (X = Cl, Br): H-1, Se-77 and C-13-NMR

    K Hiraki, T Takahashi, R Kondo, S Kagoshima, T Hasegawa, T Mochida, Y Iwasa

    SYNTHETIC METALS   120 ( 1-3 )   917 - 918   2001年3月

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    記述言語:英語   出版者・発行元:ELSEVIER SCIENCE SA  

    H-1, C-13 and Se-77 NMR measurements were performed to investigate the electronic properties of (BETS)(2)(X(2)TCNQ) (X=Cl, Br). The susceptibility was decomposed into the contributions of BETS and X(2)TCNQ site. The line broadening of the H-1/Se-77 NMR spectra were observed in the Br(2)TCNQ complex at the metal insulator transition temperature, 12 K. Non magnetic spin singlet formation on the Br2TCNC2 site was observed at 80 K by C-13 NMR. Line broadening of the H-1 NMR spectra were also observed in the Cl(2)TCNQ complex at the metal insulator transition temperature. The insulating state of the Br and Cl(2)TCNQ complexes under pressure are both magnetic. The holes on the BETS layers are relevant to the magnetic ordering.

    DOI: 10.1016/S0379-6779(00)01048-1

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  • Metal-insulator transition in donor-acceptor type superconductor, (BETS)(2)(X(2)TCNQ)

    R Kondo, T Hasegawa, S Kagoshima, T Mochida, Y Iwasa

    SYNTHETIC METALS   120 ( 1-3 )   995 - 996   2001年3月

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    記述言語:英語   出版者・発行元:ELSEVIER SCIENCE SA  

    We found that (BETS)(2)(Cl(2)TCNQ) becomes superconducting under pressure, showing a maximum critical temperature of 1.3K at 3.5kbar. The superconductivity disappears at higher pressures and is replaced by an insulating phase. its isostructural complex with larger cell parameters, (BETS)(2)(Br(2)TCNQ), displays a metal-insulator transition at 13K under ambient pressure.

    DOI: 10.1016/S0379-6779(00)00915-2

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  • ドナー・アクセプター型有機超伝導体 (BETS)2(Cl2TCNQ) 招待 査読

    近藤隆祐, 鹿児島誠一, 長谷川達生

    固体物理   35 ( 5 )   2000年5月

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  • Structure and properties of ail organic conductor (BEDT-TseF)(2)(X(1)X(2)TCNQ) (X-1,X-2=Cl,Br)

    R Kondo, S Kagoshima, T Hasegawa, T Mochida, Y Iwasa

    SYNTHETIC METALS   102 ( 1-3 )   1628 - 1629   1999年6月

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    記述言語:英語   出版者・発行元:ELSEVIER SCIENCE SA  

    We synthesized donor-acceptor charge-transfer complexes composed of BEDT-TSeF ( or "BETS") and. TCNQ derivatives and obtained isosturctual complexes represented as (BETS)(2)(X(1)X(2)TCNQ) (X-1,X-2=Cl, Br). The single crystals of (BETS)(2)(Cl(2)TCNQ) preserve the metallic state down to 2K.

    DOI: 10.1016/S0379-6779(98)00492-5

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  • Structure and properties of (BEDSe-TTF)(Fn-TCNQ) charge transfer complexes (n=1, 2, 4)

    T Mochida, H Moriyama, T Hasegawa, R Kondo, S Kagoshima, Y Iwasa

    SYNTHETIC METALS   102 ( 1-3 )   1678 - 1679   1999年6月

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    記述言語:英語   出版者・発行元:ELSEVIER SCIENCE SA  

    Charge transfer complexes of bis(ethylenediselena)-tetrathiafulvalene.(BEDSe-TTF) with a variety of Fn-TCNQ (n = 1, 2, 4, including isomers) are synthesized. In this family, only F-1,-TCNQ afforded a conducting complex. Other accepters gave mixed stack insulators, which undergo antiferromagnetic phase transitions. 2,5-F-2- and 2,3-F-2-TCNQ also yielded a polymorph with a novel type of crystal structure, showing a double-chain donor arrangement.

    DOI: 10.1016/S0379-6779(98)00578-5

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Works(作品等)

  • 一軸性圧縮下における有機導体の構造と物性

    1999年

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  • The properties and structure of organic conductor under uni-axial strain

    1999年

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  • ドナー・アクセプター型有機電導体の構造と物性

    1997年

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  • The properties and structure of donor-acceptor charge transfer salt

    1997年

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共同研究・競争的資金等の研究

  • The properties and structure of donor-accepter charge transfer salt.

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    資金種別:競争的資金

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  • The elctronic properties and structure of organic conductor under extreme condition (low temperature, high-magnetic field, high-pressure)

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  • 極限下(低温・強磁場・高圧縮(静水圧・一軸性))における有機伝導体の構造と物性

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    資金種別:競争的資金

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  • 新規有機錯体の開発

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    資金種別:競争的資金

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担当授業科目

  • 低次元量子物性学 (2021年度) 前期  - その他

  • 力学3 (2021年度) 1・2学期  - 木1,木2

  • 力学3A (2021年度) 第1学期  - 木1,木2

  • 力学3B (2021年度) 第2学期  - 木1,木2

  • 物理学実験 (2021年度) 通年  - 木5,木6,木7,木8

  • 物理学実験3 (2021年度) 通年  - 木5,木6,木7,木8

  • 量子構造物性学演習 (2021年度) 通年  - その他

  • 量子物質物性学 (2021年度) 後期  - 火3,火4

  • 電磁気学3A (2021年度) 第1学期  - 月5,月6

  • 電磁気学3B (2021年度) 第2学期  - 月5,月6

  • 電磁気学III (2021年度) 1・2学期  - 月5,月6

  • 低次元量子物性学 (2020年度) 前期  - その他

  • 力学3 (2020年度) 1・2学期  - 木1,木2

  • 力学3A (2020年度) 第1学期  - 木1,木2

  • 力学3B (2020年度) 第2学期  - 木1,木2

  • 量子構造物性学演習 (2020年度) 通年  - その他

  • 量子物質物性学 (2020年度) 後期  - 火2,火3

  • 電磁気学3A (2020年度) 第1学期  - 月5,月6

  • 電磁気学3B (2020年度) 第2学期  - 月5,月6

  • 電磁気学III (2020年度) 1・2学期  - 月5,月6

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