| Project/Area Number |
63540267
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
物性一般（含極低温･固体物性に対する理論）
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| Research Institution | Faculty of Science, Hokkaido University |
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Principal Investigator |
KUMAGAI Ken-ichi Hokkaido Univ., Dept. of Physics, Associate Professor, 理学部, 助教授 (70029560)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAJIMA Haruo Hokkaido Univ., Dept. Physics, Professor, 理学部, 教授 (10000796)
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| Project Period (FY) |
1988 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1989: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1988: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Keywords | Nuclear Magnetic Resonance / Nuclear Spin-Lattice Relaxation Time / High-T_c Superconductor / Antiferromagnetism / 磁気秩序 |
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| Research Abstract |
Nuclear quadrupole resonances (NQR) of ^<139>La and ^<63,65>Cu have been investigated in the wide range of x in hole-doped La_<2-x>M_xCuO_4 (M=Sr, Ba). The divergence of the nuclear relaxation rate of ^<139>La at T_c*-10K indicates the existence of the peculiar frustrated magnetic phase between the 3D-antiferro- magnetic and superconducting phases. The spin echo signals of ^<63,65>Cu are observed between 30-50KHz in zero external field. The spectra consist of the two component of the Cu-NQR lines for x<0.4, of which origin is still unclear. Relaxation rates, 1/T_1 and 1/T_2 are much enhanced with decreasing x. The temperature dependence of 1/T_1 for x>0.4 obeys the Korringa relation, T_1T=const., below 200K.
We have confirmed the antiferromagntic order of Cu moments in the electron-doped Ln_<2-x>Ce_xCuO_4 (Ln =Nd, Pr, Sm). Unexpected observation of nuclear magnetic resonance (NMR) with vanishingly small quadrupole interactions in the Ce-doped samples suggests that the local electronic properties at Cu site in the electron-doped oxides differ from the hole-doped ones.
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