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NMR Study of Electronic State in the Votex Core in HTSC

Research Project

Project/Area Number 14340096
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field 固体物性Ⅱ(磁性・金属・低温)
Research InstitutionHokkaido University

Principal Investigator

KUMAGAI Ken-ichi  Hokkaido University, Graduate School of Science, Professor, 大学院・理学研究科, 教授 (70029560)

Co-Investigator(Kenkyū-buntansha) FURUKAWA Yuji  Hokkaido University, Graduate School of Science, Research Associate, 大学院・理学研究科, 助手 (50280863)
KAWAMOTO Atsushi  Hokkaido University, Graduate School of Science, Associate Professor, 大学院・理学研究科, 助教授 (60251691)
Project Period (FY) 2002 – 2003
Project Status Completed (Fiscal Year 2003)
Budget Amount *help
¥14,800,000 (Direct Cost: ¥14,800,000)
Fiscal Year 2003: ¥4,100,000 (Direct Cost: ¥4,100,000)
Fiscal Year 2002: ¥10,700,000 (Direct Cost: ¥10,700,000)
KeywordsNMR / Vortex state / Antiferromagnetic order / High-Tc Superconductor / Stronglv Correlated System / 酸化物高温超伝導 / 核-スピン格子緩和時間 / 核スピン-格子緩和時間
Research Abstract

Recent experimental results have revealed that the quasiparticle excitations in the vortex state of high-T_c cuprates are very different from those of conventional s-wave superconductors. The fascinating electronic states such as the localized quasipaticle levels in the vortex core and the quasiparticle states extended from the vortex core are studied intensively. Moreover, the possibility that a vortex can accumulate a finite electric charge has been proposed. Although measurements of NMR and NQR are powerful probes for studying those issues, it is only very recent that the spatially-resolved measurements of NMR and NOR of high-T_c superconductors have come to be realized. Here we report spatially resolved NMR and NQR studies on the physics of vortex core matters.
First, we obtain an experimental evidence that a vortex in HTSC traps a finite electric charge from the high resolution measurements of the nuclear quadrupole frequencies. In slightly overdoped YBa_2Cu_3O_7, the vortex is neg … More atively charged, while in underdoped YBa_2Cu_4O_8, it is positively charged. The sign of the trapped charge is opposite to the sign predicted by the conventional BCS theory. Moreover, in both materials, the accumulated charge is much larger than expected in the ordinary superconductors These unexpected features can he attributed to the novel electronic structure of the vortex in HTSC.
Second, we report the site-selective dependence of ^<17>O-T_1 associated with the vortex state of YBa_2Cu_3O_7 and, YBa_2Cu_4O_8. We found that T_1^<-1> at the planar sites exhibits an unusual nonmonotonic NMR frequency dependence. In the region well outside the vortex core, T_1^<-1> cannot be simply explained by the density of states of the Doppler-shifted quasiparticles in the d-wave superconductor Based on T_1^<-1> in the vortex core region, we establish strong evidence that the local density of states within the vortex core is strongly reduced.
Third, we have measured spatially-resolved NMR on ^<205>Tl site of optimally-doped Tl2201compound. ^<205>TI nuclei are good probe to observe antiferromagnetic fluctuations. We obtained a clear evidence of antiferromagnetic order in the vortex core of Tl2201. NMR relaxation rate (T_1^<-1>) of the vortex core region is largely enhanced, which is not observed in the superconducting region. This T_1^<-1> enhancement is caused by magnetic fluctuations generated from antiferromagnetic moments in the vortex cores. Temperature dependences of T_1^<-1> and the spectrum broadening support also the existence of antiferromagnetic vortex core.
These features can be attributed to the novel electronic structure of the vortex in HTSC. Less

Report

(3 results)
  • 2003 Annual Research Report   Final Research Report Summary
  • 2002 Annual Research Report
  • Research Products

    (24 results)

All Other

All Publications (24 results)

  • [Publications] K.Kumagai: "Charging Effects of Vortex Core in High Temperature Superconductors Probed by Nuclear Quadrupole Interaction"Z.Naturforsch. 57a. 488-494 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] K.Kakuyanagi: "Site Selection NMR Study on electronic State in and near Vortex Core of YBa_2Cu_4O_8"J.Phys.Chem.Solids. 63. 2305-2308 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] K.Kakuyanagi: "Quasiparticle excitation in and around the vortex core of underdoped YBa_2Cu_4O_8 studied by site selecttive NMR"Phys.Rev.. B65. 060503-1-060503-4 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] K.Kakuyanagi: "NMR study on the electronic structure of the vortex state in HTSC"J.Low Temp.Physics. 131. 919-923 (2003)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] K.Kakuyanagi: "Antiferromagnetic Vortex Core in Tl_2Ba_2CuO_<6-d> : Studied by Nuclear Magnetic Resonance"Phys.Rev.Lett.. 90. 197003-1-197003-4 (2003)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] K.Kumagai: "Antiferromagnetic Vortex Core in HTSC Studies by Spatially Resolved NMR"J.Mag.Mag.Materials. 258-259. 430-435 (2003)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] M.Tonouchi, G.Oya, Y.Matsuda, K.Kumagai: "Vortex Electronic and SQUID(Toics in Applied Physics, eds.by T.Kobayashi, H.Hayakawa, M.Tonouchi)"Springer. 302 (2003)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] K.Kumagai, K.Kakuyanagi, K.Nozaki, Y.Matsuda: "Charging Effects of Vortex Core in High Temperature Superconductors Probed by Nuclear Quadrupole Interaction"Z.Naturforsch.. 57a. 488-494 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] KKakuyanagi, K.Kumagai, Y.Matsuda: "Site Selection NMR Study on Electronic State in and near Vortex Core of YBa_2Cu_4O_8"J.Phys.Chem.Solids. 63. 2305-2308 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] K.Kakuyanagi, K.Kumagai, Y.Matsuda: "Quasiparticle excitation in and around the vortex core of YBa_2Cu_4O_8 studied by site selective NMR"Phys.Rev.B.. 65. 060503-1-060503-4 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] K.Kakuyanagi, K.Kumagai, Y.Matsuda, M.Hasagawa: "NMR study on the electronic structure of the vortex state in HTSC"J.Low Temp.Physics. 131. 919-923 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] K.Kakuyanagi, K.Kumagai, Y.Matsuda, M.Hasagawa: "Antiferromagnetic Vortex Core in Tl_2Ba_2CuO_<6+d> Studied by Nuclear Magnetic Resonance"Phys.Rev.Lett.. 90. 197003-1-197003-4 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] K.Kumagai, K.Kakuyanagi, Y.Matsuda, M.Hasegawa: "Antiferromagnetic Vortex Core in HTSC Studies by Spatially Resolved NMR"J.Mag.Mag.Materials. 258-259. 430-435 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] M.Tonouchi, G.Oya, Y.Matsuda, K.Kumagai: "Vortex Electronic and SQUID"Toics in Applied Physics (eds.by T.Kobayashi, H.Hayakawa, M.Tonouchi)(Springer). 302 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] K.Kumagai, K.Kakuyanagi, Y.Matsuda, M.Hasegawa: "Antiferromagnetic Vortex Core in HTSC Studies by Spatially Resolved NMR"J.Mag.Mag.Materials. 258-259. 430-435 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] K.Kumagai, K.Kakuyanagi, Y.Matsuda, M.Hasegawa: "Antiferromagnetism Induced in the Vortex Core of Tl_2Ba_2CuO_<6+d> Proved by Spatially- Resolved NMR"Acta Physicas Polonica. B34. 471-474 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] K.Kumagai, K.Kakuyanagi, Y.Matsuda, M.Hasagawa: "Spatially-Resolved NMR Study on Antieferromanetic vortex core in HTSC"J.Low Temp.Physics. 131. 319-326 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] K.Kakuyanagi, K.Kumagai, Y.Matsuda.M.Hasagawa: "NMR Study on the electronic structure of the vortex state in HTSC"J.Low Temp.Physics. 131. 919-923 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] K.Kakuyanagi, K.Kumagai, Y.Matsuda, M.Hasagawa: "Antieferromanetic vortex core of Tl_2Ba_2CuO_<6+d> Studied by ^<205>Tl-NMR"Physica C. 388-389. 633-634 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] K.Kakuyanagi, K.Kumagai, Y.Matsuda, M.Hasagawa: "Antiferromagnetic Vortex Core in Tl_2Ba_2CuO_<6+d> : Studied by Nuclear Magnetic Resonance"Phys.Rev.Lett.. 90. 197003-197007 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] S.Takada, K.Kumagai, T.Kawashima: "NMR studies of magnetic superconductor RuSr2RECu2O8 (RE=Gd, Eu and Y)"J. Phys. Chem. Solids. 63. 2315-2318 (2002)

    • Related Report
      2002 Annual Research Report
  • [Publications] K.Kakuyanagi, K.Kumagai, Y.Matsuda: "Quasiparticle excitation in and around the vortex core of underdoped YBa_2Cu_4O_8 studied by site-selective NMR"Physical Review B. 65. 060503-1-060503-4 (2002)

    • Related Report
      2002 Annual Research Report
  • [Publications] K.Kakuyanagi, K.Kumagai, Y.Matsuda: "Site Selection NMR Study on Electronic State in and near Vortex Core of YBa_2Cu_4O_8"J. Phys. Chem. Solids. 63. 2305-2308 (2002)

    • Related Report
      2002 Annual Research Report
  • [Publications] K.Kumagai, K.Kakuyanagi, K.Nozaki, Y.Matsuda: "Charging Effects of Vortex Core in High Temperature Superconductors Probed by Nuclear Quadrupole Interaction"Z. Naturforsch.. 57a. 488-494 (2002)

    • Related Report
      2002 Annual Research Report

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Published: 2002-04-01   Modified: 2020-05-15  

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