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High field neutron diffraction studies on Er-Y-La single crystals with a long period Ising spin system

长周期伊辛自旋体系Er-Y-La单晶的高场中子衍射研究

基本信息

批准号：
01540272
负责人：
KAWANO S.
金额：
$ 1.22万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1991
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01540272/
关键词：
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

项目摘要

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.

1. 超导磁体已安装到京都大学反应堆（KUR-ND）现有的中子衍射系统上。该系统操作非常简单。2． Er_<0.9>Y_<0.05>La_<0.05>单晶的高场中子衍射表明，在4.2K和H=-3T时，摆线结构的基面成分在tlie(100)方向消失。 3、高场中子衍射发现Er_<0.9>Y_<0.1>合金在4.2K时表现出从摆线相到铁磁相的转变。 4.2K，沿 c 轴 H=0.5T。 0.5T以上所有力矩均完全排列在场方向。4． TbRu_2Si_2 和 DyRu_2Si_2 被认为是长周期伊辛自旋系统，高场中子衍射得到了两种晶体的场温相图。存在变磁相，在波状分子场理论的基础上确定了变磁相的结构并讨论了变磁相的稳定性。 5．基于自旋滑移模型讨论了类似化合物Pr-Co_2Si_2和NdCo_2Si_2的一维长周期调制结构，如Ho和Er.6的振荡磁结构所示。 XY 三角形反铁磁体 RbMnBr_3 上的高场中子衍射表明存在从一个不相称结构到另一个不相称结构的场致相变以及在高场下的自旋随角异色相变。粗略评估场-温度相图。