| Project/Area Number |
01540272
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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 |
固体物性
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| Research Institution | Kyoto University |
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Principal Investigator |
KAWANO S. Research Reactor Institute, Kyoto Univ. Research Instructor, 原子炉実験所, 助手 (70027457)
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| Project Period (FY) |
1989 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1991: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1990: ¥200,000 (Direct Cost: ¥200,000)
Fiscal Year 1989: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | neutron diffraction / high magnetic magnetic field / Ising spin system / rare earth compound / triangular lattice / metamagnetism / modulated structure / phase transition / 中性子回析 / 希土類合金 / 強磁場 / 磁化過程 |
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| Research Abstract |
1. Attachment of a superconducting magnet has been made to an existing neutron diffraction system at the Kyoto University Reactor -(KUR-ND). This system can be very easily operated.
2. High field neutron diffraction of Er_<0.9>Y_<0.05>La_<0.05> single crystal reveals that the basal plane component of a cycloidal structure disappears at, 4.2K and H=- 3T in tlie(100)direction.
3, High field neutron diffraction finds that Er_<0.9>Y_<0.1> alloy exhibits a transition from cycloidal to ferromagnetic phase at 4.2K and at H=0.5T along the c-axis. Over 0.5T all the moments are fully arranged in the field direction.
4. High field neutron diffraction of TbRu_2Si_2 and DyRu_2Si_2, which are considered to be a long period Ising spin system, yields field-temperature phase a diagram for both crystals. There are metamagnetic phases, whose structures are determined and their stability is discussed oil the basis of a wave-like molecular field theory.
5. One-dimensionally long period modulated structures of similar compounds Pr-Co_2Si_2 and NdCo_2Si_2 are discussed on the basis of a spin slip model, as seen in oscillatory magnetic structures of Ho and Er.
6. High field neutron diffraction on an XY triangular antiferromagnet RbMnBr_3 gives an existence of field induced phase transition from an incommensurate to another incommensurate structure and also of a spin flop phase at high fields. A field-temperature phase diagram is roughly evaluated.
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