Development of Neutron 4-circle Diffractometer for studies of Structural Phase Transition

用于结构相变研究的中子四环衍射仪的研制

• 批准号: 09354004
• 负责人: NODA Yukio
• 金额: $ 23.17万
• 依托单位: Tohoku University (1998-2000)Chiba University (1997)
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A).
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09354004/
• 关键词: Neutron Scattering; Single Crystal; 4-circle Diffractometer; Structural Phase transition; 中性子回析; 4軸回析装置; 4軸回折計

We have developed a 4-circle diffractometer for a single crystal experiment at the guidehall of the reactor JRR3M-JAERI (Japanese Research Reactor) at Tokai. The name of the diffractometer was adapted as FONDER (Four-Circle Off-center Type Diffractometer). We also developed a horizontally and vertically bend monochromatore with silicon plates. We could succeed to get well-focused neutron beam as a size of 1cm times 2cm at the sample position by using nine Si422 plates. Wavelength of the neutron is 1.54A at the moment and the maximum scattering angle of a sample is 156 degree. We investigated several hydrogen bond materials like squaric acid and MeHPLN, oxide materials such as CuGeO_3, an oxide ferroelecric and antiferromagnetic compound YMn_2O_5, and obtained their structure and the phase transition scheme. We also studied structure and magnetic structure of manganese fluoride MnF_2. Very good R-factor was obtained, and electron density which is carrying spins was obtained. Maximum entropy method and Fourier synthesis methods were applied to btain nuclear density with great success. Structure analysis with neutron is now available.

我们在东海的JRR 3 M-JAERI（日本研究堆）的导向大厅研制了一台用于单晶实验的四圆衍射仪。衍射仪的名称改为FONDER（四圆偏心型衍射仪）。我们还研制了一种水平和垂直弯曲单色器与硅板。用9块Si 422板就可以在样品处得到1cm × 2cm的聚焦中子束。此时中子的波长为1.54A，样品的最大散射角为156度。我们研究了方酸和MeHPLN等氢键材料，CuGeO_3和YMn_2O_5等氧化物材料，得到了它们的结构和相变图式。研究了氟化锰MnF_2的结构和磁结构。获得了非常好的R因子，并且获得了携带自旋的电子密度。最大熵法和傅里叶综合法被用来计算核密度，并取得了很大的成功。现在可以用中子进行结构分析。

项目成果

Y.Noda: "New Four-Cicle Diffractometer for Neutrin Scattering and its Capability"Hamon J.Jpn Soc.Neutron Scie. 11(in Japanese)(in press). (2001)

Y.Noda：“用于中微子散射的新型四环衍射仪及其功能”Hamon J.Jpn Soc.Neutron Scie。

Y.Noda et al.: "High-Resolution Powder Diffractometry to Study the Phase Transition of h-BaTiO_3"Jpn.J.Appl.Phys.. S38-1. 73-76 (1999)

Y.Noda 等人：“高分辨率粉末衍射法研究 h-BaTiO_3 的相变”Jpn.J.Appl.Phys..S38-1。

M.Takahashi: "Magnetic Short-range Order in Rt-Mn Spin-glass Alloys"J.Phys.Soc.Jpn(suppl.). 70. 136-138 (2001)

M.Takahashi：“Rt-Mn自旋玻璃合金中的磁性短程有序”J.Phys.Soc.Jpn（增刊）。

Y.Noda: "Remarkable Improvement of the structural Data in h-BaTiO_3 with short Wavelength Nontrons"J.Phys.and Chem.Solid. 60. 1415-1418 (1999)

Y.Noda：“短波长非电子对 h-BaTiO_3 结构数据的显着改进”J.Phys.and Chem.Solid。

Y.Noda et al.: "Neutron and Synchrotron Radiation Studies of the Phase Transition of h-BaTiO_3"Ferroelectrics. 217. 1-7 (1998)

Y.Noda 等人：“h-BaTiO_3 相变的中子和同步辐射研究”铁电体。