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1998 Fiscal Year Final Research Report Summary

Nuclear Magnetic Resonance Study on the Charge Density Wave (CDW) in Copper Sulfide Spinel CuV_2S_4

Research Project

Project/Area Number 09640439
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field 固体物性Ⅱ(磁性・金属・低温)
Research InstitutionUniversity of Tokushima

Principal Investigator

KISHIMOTO Yutaka  University of Tokushima, Faculty of Engineering Lecturer, 工学部, 講師 (80201458)

Co-Investigator(Kenkyū-buntansha) OHNO Takashi  University of Tokushima, Faculty of Engineering Associate Professor, 工学部, 助教授 (70035640)
Project Period (FY) 1997 – 1998
KeywordsCopper Sulfide / Spinel-type Compound / CuV_2S_4 / Charge Density Wave (CDW) / NMR / Spin-Lattice Relaxation / Knight Shift / High T_c Superconductor
Research Abstract

CuV_2S_4 shows the charge density wave (CDW) transition which is a typical low dimensional property although CuV_2S_4 is a three dimensional substance. At high temperatures, all the ^<63>Cu, ^<65>Cu and ^<51>V spin-lattice relaxation rates obey the Korringa law, and CuV_2S_4 is considered to be a simple metal at high temperatures. ^<51>V relaxation rate shows the Arrhenius type temperature dependence below 90 K, which indicates an energy gap due to CDW.Below 75 K, ^<51>V relaxation rate obeys the Korringa law again, which indicates its energy gap is anisotropic. The ratio of ^<63>Cu and ^<65>Cu relaxation rates is close to the square of the ratio of their gyromagnetic ratios at high temperatures, which tells us its relaxation mechanism is magnetic and is consistent with obeying the Korringa law. But with approaching CDW transition temperature, it reverses and becomes the square of the ratio of their quadrupole moments. The ^<63>Cu and ^<65>Cu relaxation rate becomes to diverge at CDW transition temperature, which indicates that the electric field gradients at Cu site becomes larger. This fact agrees with the fact that ^<63>Cu and ^<65>Cu NMR spectra disappear due to CDW below 83 K.^<51>V Knight shift ^<51>K is negative at high temperatures because the core polarization is effective due to V 3d electrons. The magnitude of ^<51>K becomes smaller with approaching CDW transition temperature and changes to a positive value after CDW transition, which indicates that the paired two electrons are distributed in each CDW wave length. The hyperfine coupling constant of Cu is positive, which seems to indicate the existence of the super transferred hyperfine coupling in CuV_2S_4 as observed in copper oxide high T_c superconductors.

  • Research Products

    (19 results)

All Other

All Publications (19 results)

  • [Publications] Y.Kishimoto,T.Ohno K.Sumiyama,K.Suzuki: "^<51>V Knight Shifts in the Superconducting State of V_3Si" J.Magn.Magn.Mat.177-181. 367-368 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] T.Ohno,K.Koyama and H.Yasuoka: "Changes in the On-Site Holes of Plane Cu(2) and Chain Cu(1) in Y_<1-x>Pr_xBa_2Cu_3O_<7-y>" J.Magn.Magn.Mat.177-181. 537-538 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] F.Raffa,T.Ohno D.Brinkmann et al.: "Isotope Dependence of the Spin Gap in YBa_2Cu_4O_8 as Determined by Cu NQR Relaxation" Phy.Rev.Lett.81. 5912-5915 (1998)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] T.Ohno and Y.Kishimoto: "^<63>Cu and ^<51>V spin-spin relaxation rates in CuV_2S_4" Physica B. in press. (1999)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Y.Kishimoto,Ohno et al.: "^<63>CU NMR of CuTi_2S_4" Blletine Eng.Tokushima Univ.in press. (1999)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] T.Ohno and K.Asayama: "^<63>Cu NQR Study on Isotope Effect in YBa_2Cu_4O_8" J.Phys.Soc.Jpn.in press. (1999)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] T.Ohno, Y.Kishimoto, T.Kanashiro, M.Miyamoto, T.Tanaka and K.Miyatani: "Change in ^<51>V Relaxation Rates due to CDW in CuV_2S_4" Z.Naturforsch.51a. 773-776 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] T.Ohno, Y.Kishimoto and K.Miyatani: "Changes in ^<63>Cu and ^<65>Cu NMR Relaxation Rates Due to CDW Transition in CuV_2S_4" Physica B. 230-232. 988-991 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Y.Kishimoto, T.Ohno, T.Kanashiro and Y.Michihiro: "^<51>V Knight Shift of a C15 Laves Phase Superconductor HfV_2" Physica B. 237-238. 312-314 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] T.Ohno, K.Koyama and H.Yasuoka: "CuNQR and Hole Transfer in R_<1-x>Pr_xBa_2Cu_3O_<7-delta>" Physica B. 237-238. 100-102 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] H.Nishihara, T.Ohno, H.Yoshida and Y.Kishimoto: "Powder Spectra of ^<11>B NMR in the Magnetically Ordered State of CeRh_3B_2" Physica B. 237-238. 218-220 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] T.Ohno, T.Kanashiro, Y.Yamada, T.Yamanishi, T.Tanaka, Y.Kishimoto, K.Nakamura and Y.Michihiro: "^<59>Co Spin-Lattice Relaxation in Superconducting CoSi_2" Physica B. 237-238. 307-309 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Y.Kishimoto, T.Ohno, T.Kanashiro, T.Takai, K.Nakamura, K.Sumiyama, T.Hihara and K.Suzuki: "^<51>V Knight Shifts in the Superconducting State of V_3Si" J.Magn.Magn.Mat.177-181. 367-368 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] T.Ohno, K.Koyama and H.Yasuoka: "Changes in the On-Site Holes of Plane Cu (2) and Chain Cu (1) in Y_<l-x>Pr_xBa_2Cu_3O_<7-y>" J.Magn.Magn.Mat.177-181. 537-538 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] T.Ohno, Y.Homma, Y.Shiokawa, T.Nishioka, M.Kontani, K.Sumiyama and K.Suzuki: "AC Susceptibility of Amorphous Dense Kondo UPd_2Al_3" J.Magn.Magn.Mat.177-181. 453-454 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] F.Raffa, T.Ohno, M.Mali, J.Roos, D.Brinkmann, K.Conder and M.Eremin: "Isotope Dependence of the Spin Gap in YBa_2Cu_4O_8 as Determined by Cu NQR Relaxation" Phys.Rev.Lett.81. 5912-5915 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] T.Ohno and Y.Kishimoto: "^<63>Cu and ^<51>V spin-spin relaxation rates in CuV_2S_4" Physica B. (in press). (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Y.Kishimoto, T.Ohno, K.Miyatani, T.Kanashiro, Y.Michihiro, K.Nakamura, K.Koyama, T.Saito, K.Mizuno and K.Magishi: "^<63>Cu NMR of CuTi_2S_4" Bulletin of Faculty of Engineering, Univ.Tokushima. (in press). (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Takashi Ohno: "Nuclear Magnetic Resonance of Copper Sulfide Spinels (in Japanese)" Solid State Physics. 31. 483-492 (1996)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 1999-12-08  

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