Meta-magnetism in Uranium-base Ferromagnetic Superconductors by Magnetic Compton Scattering

磁康普顿散射在铀基铁磁超导体中的超磁性

• 批准号: 15540356
• 负责人: SAKURAI Yoshiharu
• 金额: $ 1.79万
• 依托单位: Japan Synchrotron Radiation Research Institute
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2004
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15540356/
• 关键词: UGe2; Magnetic Compton scattering; Superconductivity; Ferromagnetism; High Pressure; 強磁性超伝導体; メタ磁性転移; 磁気コンプトン散乱; 軌道

Coexistence of ferromagnetism with superconductivity in UGe_2 has drawn much attention form many research scientists. The meta-magnetism observed in the ferromagnetic phase has been intensively studied in connection with the mechanism of the superconductivity. The aim of this project is to understand the meta-magnetism in an atomic-scale level by using the magnetic Compton scattering technique.We have carried out magnetic Compton scattering experiments on ferromagnetic UGe_2 at ambient pressure and have not find any anomalies in spin moment across the meta-magnetic transition temperature of 32 K. By combining with the magnetization data available in literatures, we have successfully separated the spin and orbital moments. The ratio of orbital moment to spin moment (L/S) is determined to be almost constanat, L/S=-0.2〜-2.3,over the temperature range between 10 K and 60 K. In the line-shape of magnetic Compton scattering (magnetic Compton profile), however, we have found significant changes across the meta-magnetic transition.In order to explain the origin of the changes observed in magnetic Compton profiles, we have fit atomic profiles of U-5f orbitals with different magnetic quantum number (m). The value of L/S predicted by the present fit is in good agreement with the above-mentioned, experimental values, showing the validity of the present model fitting.The fitting results show that the observed changes in the magnetic Compton profiles are caused by the changes of the weight of the m=1 and m=2 orbital states, suggesting strong fluctuation in the hybridization with Ge p states.In addition, we have performed high-pressure measurements at 1.0 GPa. The data-processing is in progress.

UGe_2中的铁磁性与超导电性共存引起了许多科学家的关注。在铁磁相中观察到的亚磁性已被广泛研究，并与超导机制相联系。本项目的目的是利用磁康普顿散射技术在原子尺度上理解亚磁性。我们在常压下对铁磁性UGe_2进行了磁康普顿散射实验，在32K的亚磁转变温度范围内没有发现自旋矩的任何反常现象。结合文献中提供的磁化数据，我们成功地分离了自旋矩和轨道矩。在10~60K的温度范围内，轨道矩与自旋矩之比(L/S)几乎不变，L/S=-0.2~-2.3。在磁康普顿散射的线形(磁康普顿轮廓)中，我们发现亚磁康普顿跃迁发生了显著的变化。为了解释磁康普顿轮廓变化的原因，我们拟合了不同磁量子数(M)的U-5f轨道的原子轮廓。拟合结果表明，磁康普顿分布的变化是由m=1和m=2轨道态的重量变化引起的，表明与Ge-p态的杂化有很强的涨落。此外，我们还在1.0 GPa下进行了高压测量。数据处理正在进行中。

项目成果

A Cauchois-type X-ray spectrometer for momentum density studies on heavy-element materials

用于重元素材料动量密度研究的 Cauchois 型 X 射线光谱仪

• 发表时间: 2004
• 期刊: Journal of Physics and Chemistry of Solids 65
• 作者: Y.Sakurai;M.Itou
• 通讯作者: M.Itou

Magnetic Compton scattering study of CeRh3B2

CeRh3B2 的磁康普顿散射研究

• DOI: 10.1088/0953-8984/15/28/348
• 发表时间: 2003
• 期刊: Journal of Physics: Condensed Matter
• 作者: Y. Sakurai;M. Itou;J. Tamura;S. Nanao;A. Thamizhavel;Y. Inada;A. Galatanu;E. Yamamoto;Y. Ōnuki
• 通讯作者: Y. Ōnuki

A Magnetic Compton scattering study of Sr_2FeMoO_6

Sr_2FeMoO_6的磁康普顿散射研究

• 发表时间: 2004
• 期刊: Journal of Physics : Condensed Matter 16
• 作者: Y.Sakurai;A.Deb;M.Itou;N.Hiraoka;A.Koizumi;Y.Tomioka;Y.Tokuta
• 通讯作者: Y.Tokuta

A magnetic Compton scattering study of double perovskite Sr_2FeMoO_6

双钙钛矿Sr_2FeMoO_6的磁康普顿散射研究

• 发表时间: 2004
• 期刊: Journal of Physics : Condensed Matter 16・48
• 作者: Y.Sakurai;A.Deb;M.Itou;N.Hiraoka;A.Koizumi;Y.Tomioka;Y.Tokura
• 通讯作者: Y.Tokura