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2006 Fiscal Year Annual Research Report

フラストレート系における超伝導探索

Research Project

Project/Area Number 16076209
Research InstitutionNagoya University

Principal Investigator

佐藤 正俊  名古屋大学, 大学院理学研究科, 教授 (40092225)

Co-Investigator(Kenkyū-buntansha) 室町 英治  物質・材料研究機構, ナノ物質ラボ, ラボ長 (30343833)
Keywords超伝導 / 物質開発 / コバルト酸化物 / フラストレーション / 核磁気共鳴 / 中性子散乱 / ソフト化学合成 / 構造解析
Research Abstract

Na_xCoO_2・yH_20の超伝導機構の解明と新超伝導物質開発を主目的に研究した。
(化学的観点から)前年度に引き続き、水和コバルト超伝導体Na_x(H3O)。(H_2O)_nCoO_2に関して、ソフト化学合成手法により、良くキャラクタライズされた良質試料を作成した。特に、合成プロセスの最終段階で一定量のNaOH水溶液を添加することで、コバルト価数がほぼ一定(s=+3.47〜+3.50)で、ナトリウム量(x)とオキソニウムの量(z)を制御した一連の試料を作成した(NaOHシリーズ)。NaOHシリーズは、前年度のHClを添加した試料(HClシリーズ、s=+3.40〜+3.41)とは全く異なった超伝導相図を与え、特に、HC1シリーズに見られた非超伝導磁気相は出現しなかった。このことは、本系における試料の同定には、S及びZ/Xのように、二つの組成パラメーターを決定する必要があることを示している。
(物理的観点から)Na_xCoO_2・yH_20の研究では、その磁気フラストレーションやCoのスピン状態変化(軌道励起)の役割にちゅうもくして、銅酸化物に関して得られた理解をガイドラインに、中性子散乱やNMRによるデータを詳細にとった。特に、これまでにクーパー対がsinglet状態にあることを明らかにしたことが重要であるが、さらに転移温度場をNMR四重極周波数VQの関数としてプロットして作成された相図に見られる超伝導相を分断する非超伝導相の起源が何であるかについて、極めて精密なデータをとった。この結果は、非超伝導相が電荷秩序の出現を基本にして現れたものである。
Na_xCoO_2・yH_20に関する研究のほかに、新物質、新現象の探索的研究が進められ、様々な発見、現象の解明がなされた。

  • Research Products

    (59 results)

All 2007 2006

All Journal Article (59 results)

  • [Journal Article] New Type Phase Transition of Li_2RUO_3 with Honeycomb Structure2007

    • Author(s)
      Yoko Miura et al.
    • Journal Title

      J. Phys. Soc. Jpn. 76 No. 3

      Pages: 033705(1-4)

  • [Journal Article] Successive Magnetic Transitions of the Kagome Staircase Compound Co_3V_2O_8 Studied in Various Magnetic Fields2007

    • Author(s)
      Yukio Yasui et al.
    • Journal Title

      J. Phys. Soc. Jpn. 76 No.3

      Pages: 034706 (1-8)

  • [Journal Article] Ferroelectric Transition Induced by the Incommensurate Magnetic Ordering in LiCuVO_42007

    • Author(s)
      Yutaka Naito et al.
    • Journal Title

      J. Phys. Soc. Jpn. 76 No.2

      Pages: 023708 (1-3)

  • [Journal Article] Unusual Behavior of the Anomalous Hall Effect of Systems With Non-Trivial Magnetic Structures2007

    • Author(s)
      M.Sato
    • Journal Title

      J. Mag. Mag. Mater. 310

      Pages: 1021-1023

  • [Journal Article] Studies on the Anomalous Hall Effect of Nd_2Mo_2O_7-Test of the Chirality Mechanism2007

    • Author(s)
      Y.Yasui et al.
    • Journal Title

      J. Mag. Mag. Mater.

      Pages: e544-e546

  • [Journal Article] MAGNETIC MEASUREMENTS AND NEUTRON STUDIES ON YBaCo_4O_7 AND LuBaCo_4O_72007

    • Author(s)
      M.Soda et al.
    • Journal Title

      J. Mag. Mag. Mater. 310

      Pages: e441-e442

  • [Journal Article] NMR STUDIES OF SUCCESSIVE TRANSITION IN Na_<0.5>CoO_22007

    • Author(s)
      Y.Kobayashi et al.
    • Journal Title

      J. Mag. Mag. Mater. 310

      Pages: 675-677

  • [Journal Article] MAGNETIC AND THERMAL PROPERTIES OF Co_3V_2O_8 AND Ni_3V_2O_82007

    • Author(s)
      Y.Kobayashi et al.
    • Journal Title

      J. Mag. Mag. Mater. 310

      Pages: 1160-1161

  • [Journal Article] STRUCTURAL STUDIES OF THE PYROCHLORE-RELATED SPIN-1/2 SYSTEM Ag_2Cu_2O_32007

    • Author(s)
      D.Uematsu et al.
    • Journal Title

      J. Mag. Mag. Mater. 310

      Pages: 387-388

  • [Journal Article] NMR AND NEUTRON SCATTERING STUDIES ON Na_xCoO_2・yH_2O2007

    • Author(s)
      M.Sato et al.
    • Journal Title

      J. Mag. Mag. Mater. 310

      Pages: 666-668

  • [Journal Article] STUDIES OF SUCCESSIVE TRANSITIONS IN K_<0.5>CoO_22007

    • Author(s)
      M.Yokoi et al.
    • Journal Title

      J. Mag. Mag. Mater. 310

      Pages: 672-674

  • [Journal Article] OBSERVATION OF IN-PLANE ORDERING OF D_2O MOLECULES IN Na_xCoO_2・yD_2O BY NEUTRON DIFFRACTION2007

    • Author(s)
      T.Moyoshi et al.
    • Journal Title

      J. Mag. Mag. Mater. 310

      Pages: 654-656

  • [Journal Article] STUDIES OF MAGNETIC BEHAVIOR OF SPIN-1/2 FRUSTRATED SYSTEM Hg_2Cu_2F_6S2007

    • Author(s)
      S.Kawabata et al.
    • Journal Title

      J. Mag. Mag. Mater. 310

      Pages: 1295-1296

  • [Journal Article] HALL RRSISTIVITY OF RBaCo_2O_<5.5> (R = Y AND RARE EARTH ELEMENTS)2007

    • Author(s)
      T.Fujita et al.
    • Journal Title

      J. Mag. Mag. Mater. 310

      Pages: e234-e236

  • [Journal Article] SPIN GAP BEHAVIOR OF DISTORTED HONEY-COMB LATTICE SYSTEM Na_3Cu_2SbO_62007

    • Author(s)
      Y.Miura et al.
    • Journal Title

      J. Mag. Mag. Mater. 310

      Pages: e389-e391

  • [Journal Article] New misfit-layered cobalt oxide (CaOH)_<1.14>CoO_22007

    • Author(s)
      Shizuya M, et al.
    • Journal Title

      J. Solid State Chem 180 No.1

      Pages: 249-259

  • [Journal Article] Modulated structure of the composite crystal [2CaOH](k)CoO2 (k=0.576)2007

    • Author(s)
      Isobe M, et al.
    • Journal Title

      J. Phys. Soc. Jpn 76 No.1

      Pages: 014602

  • [Journal Article] Origin of the monoclinic-to-monoclinic phase transition and evidence for the centrosymmetric crystal structure of BiMnO32007

    • Author(s)
      Belik AA, et al.
    • Journal Title

      J. Am. Chem. Soc 129 No.4

      Pages: 971-977

  • [Journal Article] Post-spinel transition and magnetic properties of LiMn_2O_42007

    • Author(s)
      Yamaura K, et al.
    • Journal Title

      Phys. Status Solidi. B 244 No.1

      Pages: 285-289

  • [Journal Article] High-pressure high-temperature (HPHT) synthesis and magnetism of Sr_2Y_<1.5.>Ce_<0.5>Cu_2O_<10> compounds with M=Ru, Mn, and Cr2007

    • Author(s)
      Awana VPS, et al.
    • Journal Title

      Mater. Lett. 61 No.3

      Pages: 774-778

  • [Journal Article] Physical property characterization of Fe-tube encapsulated and vacuum annealedbulk MgB22007

    • Author(s)
      Awana VPS, et al.
    • Journal Title

      Solid State Commun. 139 No.6

      Pages: 306-309

  • [Journal Article] Structural Studies of Pyrochlore-Related Spin-1/2 System Ag_2Cu_2O_32006

    • Author(s)
      D.Uematsu et al.
    • Journal Title

      J. Phys. Soc. Jpn. 75 No. 12

      Pages: 124601-(1-5)

  • [Journal Article] Anomalous Hall Resistivity of TaBaCo_2O_<5.53> with Non-trivial Magnetic Structure2006

    • Author(s)
      T.Fujita et al.
    • Journal Title

      J. Phys. Soc. Jpn. 75 No. 11

      Pages: 114710-(1-7)

  • [Journal Article] Existence of the Co^3+ Low Spin State in TbBaCo_2O_<5.5>2006

    • Author(s)
      M.Soda et al.
    • Journal Title

      J. Phys. Soc. Jpn. 75 No. 10

      Pages: 104708-(1-7)

  • [Journal Article] Studies of the Anomalous Hall Effect and Magnetic Structure of Nd_2Mo_2O_7-Test of the Chirality Mechanism-2006

    • Author(s)
      Yukio Yasui et al.
    • Journal Title

      J. Phys. Soc. Jpn. 75 No.8

      Pages: 84711-(1-11)

  • [Journal Article] Spin-Gap Behavior of Na_3Cu_2SbO_6 with Distorted Honeycomb Structure2006

    • Author(s)
      Yoko Miura et al.
    • Journal Title

      J. Phys. Soc. Jpn. 75 No.8

      Pages: 84707-(1-6)

  • [Journal Article] Magnetic properties of superconducting cobalt oxides Na_xCoO_2・yH_2O2006

    • Author(s)
      Yoshiaki KOBAYASHI et al.
    • Journal Title

      J. Phys. Soc. Jpn. 75 No. 7

      Pages: 74717-(1-6)

  • [Journal Article] Search for Magnetic Excitation Spectra of Na_xCoO_2・yD_2O-Neutron Scattering-2006

    • Author(s)
      Taketo Moyoshi et al.
    • Journal Title

      J. Phys. Soc. Jpn. 75 No. 7

      Pages: 074705-(1-6)

  • [Journal Article] Magnetic Structure of YBaCo_4O_7 with Co-O Kagome- and Triangular Lattices2006

    • Author(s)
      Minoru Soda et al.
    • Journal Title

      J. Phys. Soc. Jpn. 75 No. 5

      Pages: 054707-(1-6)

  • [Journal Article] Magnetic and Metal-Insulator Transitions in β-Na_<0.5>CoO_2 and γ-K_<0.5>CoO_2-NMR and Neutron Diffraction Studies-2006

    • Author(s)
      H.Watanabe et al.
    • Journal Title

      J. Phys. Soc. Jpn. 75 No. 3

      Pages: 034716-(1-8)

  • [Journal Article] Photoemission Study of RBaCo_2O_<6-δ> (R=Tb, Nd, δ=0.5, 1.0)2006

    • Author(s)
      K.Takubo et al.
    • Journal Title

      Phys. Rev. B 73

      Pages: 075102

  • [Journal Article] Electron-phonon coupling reflecting dynamic charge inhomogeneity in copper-oxide superconductors2006

    • Author(s)
      D.Reznik et al.
    • Journal Title

      Nature. 440

      Pages: 1170-1173

  • [Journal Article] Impact of Co and Mo substitution at Ru-site in RuSr2Eu 1.5Ce0.5Cu2O10-delta magneto-superconductor2006

    • Author(s)
      Awana VPS, et al.
    • Journal Title

      Mod. Phys. Lett B20 No.29

      Pages: 1901-1908

  • [Journal Article] Unconventional superconductivity induced by quantum critical fluctuations in hydrate cobaltate Na_x(H_3O)_ZCoO_<2-y>H_2O Relationship between magnetic fluctuations and superconductivity revealed by Co nuclear quadrupole resonance2006

    • Author(s)
      Ihara Y, et al.
    • Journal Title

      J. Phys. Soc. Jpn. 75 No. 12

      Pages: 124714

  • [Journal Article] Monoclinic phase of the misfit-layered cobalt oxide (Ca_<0.85>OH)_<1.16>CoO_22006

    • Author(s)
      Shizuya M, et al.
    • Journal Title

      J. Solid State Chem. 179 No. 12

      Pages: 3974-3980

  • [Journal Article] Magneto-transport of high TCR (temperature coefficient of resistance) La_<2/3>Ca_<1/3>MnO_3 : Ag polycrystalline composites2006

    • Author(s)
      Awana VPS, et al.
    • Journal Title

      Solid State Commun. 140No.9-10

      Pages: 410-415

  • [Journal Article] Specific-heat evidence of strong electron correlations and thermoelectric properties of the ferromagnetic perovskite SrCoO_<3-δ>2006

    • Author(s)
      Balamurugan S, et al.
    • Journal Title

      Phys. Rev. B74 No. 17

      Pages: 172406

  • [Journal Article] Superconductivity in the hexagonal-layered molybdenum carbide eta-Mo_3C_22006

    • Author(s)
      Yamaura K, et al.
    • Journal Title

      Phys. Rev. B74 No. 18

      Pages: 184510

  • [Journal Article] Magnetic properties of BiMnO_3 studied with dc and ac magnetization and specific heat2006

    • Author(s)
      Belik AA, et al.
    • Journal Title

      Inorg. Chem. 45 No.25

      Pages: 10224-10229

  • [Journal Article] Magnetic properties of the highly iron-doped rutile TiO_2 nano crystals2006

    • Author(s)
      Yamaura K, et al.
    • Journal Title

      Mater. Res. Bull. 41 No.11

      Pages: 2080-2087

  • [Journal Article] High-pressure synthesis of the perovskite rhodate CaRhO_32006

    • Author(s)
      Yamaura K, et al.
    • Journal Title

      Physica C 445

      Pages: 54-56

  • [Journal Article] Anomalous lattice expansion of RuSr_2Eu_<1.5>Ce_<0.5>Cu_2O_<10-δ> (Ru-1222) magneto superconductor : A low temperature X-ray diffraction study2006

    • Author(s)
      Awana VPS, et al.
    • Journal Title

      Physica C 445

      Pages: 97-101

  • [Journal Article] Valence and Na content dependences of superconductivity in Na_xCo_O_2yH_2O2006

    • Author(s)
      Sakurai H, et al.
    • Journal Title

      Phys. Rev. B74 No.9

      Pages: 092502

  • [Journal Article] Atomic force microscope based Iithography of YBa2Cu3O7-delta thin films2006

    • Author(s)
      Wimbush SC, et al.
    • Journal Title

      Jpn. J. Appl. Phys 45

      Pages: 5742-5745

  • [Journal Article] Fluxoid jump coupled high critical current density of nano-Co_3O_4 doped MgB_22006

    • Author(s)
      Awana VPS, et al.
    • Journal Title

      Supercond. Sci. Technol. 19

      Pages: 551-555

  • [Journal Article] Spinel-to-CaFe_2O_4-type structural transformation in LiMn_2O_4 under high pressure2006

    • Author(s)
      Yamaura K, et al.
    • Journal Title

      J. Am. Chem. Soc. 128

      Pages: 9448-9456

  • [Journal Article] Synthesis and physical characterization of superconductivity-magnetism crossover compound RuSr_2EuCeCu_2O_<10-δ>2006

    • Author(s)
      Awana VPS, et al.
    • Journal Title

      Solid State Commun. 138

      Pages: 452-456

  • [Journal Article] Absence of ferromagnetism in bulk polycrystalline Zn_<0.9>Co_<0.1>O2006

    • Author(s)
      Yin S, et al.
    • Journal Title

      Phys. Rev. B 73No.22

      Pages: 224408

  • [Journal Article] Structural and magnetic properties of high-pressure/high-temperature synthesized (Sr_<1-x>R_x)CoO_3 (R = Y and Ho) perovskites2006

    • Author(s)
      Balamurugan S, et al.
    • Journal Title

      J. Solid. State Chem. 179 No.7

      Pages: 2231-2236

  • [Journal Article] Quantum critical point of γ-Na_xCoO_22006

    • Author(s)
      Sakurai H, et al.
    • Journal Title

      Physica B 378-380

      Pages: 121-122

  • [Journal Article] Knight shift of triangular lattice superconductor Na_<0.35>CoO_2・1.3H_2O2006

    • Author(s)
      Michioka C, et al.
    • Journal Title

      Physica B 378-380

      Pages: 628-629

  • [Journal Article] ^<23>Na-NMR study of layered superconductor Na_xCoO_<2・y>H_2O2006

    • Author(s)
      Ohta H, et al.
    • Journal Title

      Physica B 378-380

      Pages: 859-860

  • [Journal Article] Various analyses of specific heat for the order parameter of superconductor Na_<0.35>coO_2・1.3H_2O2006

    • Author(s)
      Sun CP, et al.
    • Journal Title

      Physica B 378-380

      Pages: 865-866

  • [Journal Article] Phase diagram in bilayered-hydrate Na_xCoO_<3-y>H_2O revealed by Co nuclear quadrupole resonance2006

    • Author(s)
      Ishida K, et al.
    • Journal Title

      Physica B 378-380

      Pages: 869-870

  • [Journal Article] Metallic conductivity and a Ca substitution study of NaRh_2O_4 comprising a double chain system2006

    • Author(s)
      Yamaura K, et al.
    • Journal Title

      Physica B 378-380

      Pages: 1134-1135

  • [Journal Article] High-pressure synthesis crystal structures, and characterization of CdVO_<3-δ> and solid solutions CdVO_3-NaVO_32006

    • Author(s)
      Belik AA, et al.
    • Journal Title

      J. Solid. State Chem. 179 No.6

      Pages: 1650-1658

  • [Journal Article] Crystal structure and high-pressure properties of γ-Mo_2N determined by neutron powder diffraction and X-ray diffraction2006

    • Author(s)
      Bull CL, et al.
    • Journal Title

      J. Solid. State Chem. 179 No.6

      Pages: 1762-1767

  • [Journal Article] Ferromagnetism in two-dimensional Ti_<0.8>Co_<0.2>O_2 nanosheets2006

    • Author(s)
      Osada M, et al.
    • Journal Title

      Phys. Rev B73No.15

      Pages: 153301

  • [Journal Article] Superconducting phase diagram of Na_xCoO_2yH_2O2006

    • Author(s)
      Sakurai H, et al.
    • Journal Title

      Physica C 445

      Pages: 31-34

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Published: 2008-05-08   Modified: 2016-04-21  

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