Research of High-Field Magnetization in Transuranium Neptunium Compounds

超铀镎化合物的高场磁化研究

• 批准号: 17540324
• 负责人: SUGIYAMA Kiyohiro
• 金额: $ 2.3万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2005
• 资助国家: 日本
• 起止时间: 2005 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-17540324/
• 关键词: High Magnetic Field; Transuranium compounds; Neptunium; Measurements of Magnetization; Strongly Correlated Electron Systems; Metamagnetism; Magnetic Anisotropy; Quatrupolar Interaction

We measured high-field magnetization in NpRhGa_5 and NpO_2 and related compound, UO_2. The New transient memory equipment 'Sigma90' was introduced, which was too expensive to buy with this foundation, and developed the related measurement systems by this foundation. Then high-quality magnetization data can be obtained with this new measurement system. The magnetic phase diagram of NpRhGa_5 is obtained by the measurement of the temperature dependence of the high-field magnetization. According to this results, the large magnetic moment of about 1 μ_B/Np with magnetic anisotropy of [110] changes to the small magnetic moment of about 0.5 μ_B/Np with no magnetic anisotropy at the metamagnetic first order transition. The ground state of low temperature state is represented by the theory of Kiss and Kuramoto with the quadrupolar interaction. This means that the system can be explained by the local moment 5f-electron model. On the other hand, the de Haas-van Alphen oscillations are measured and this results shows the 5f-electron is itinerant. These results shows that the magnetism of this compound cannot be explained by the simple localized or itinerant f-electron model. The magnetization of NpO_2 shows always linear below T_N.. This result shows the antiferromagnetic interaction between 5f-electrons is very strong. These results are represented in the international conferences, SCES05 (Vienna ), Handai forum (Hanoi), ICM2006 (Kyoto) and RHMF2006 (Sendai). These results also be represented in the JPS meetings.

我们测量了NpRhGa_5和NpO_2以及相关化合物UO_2的高场磁化强度，并在此基础上开发了相关的测量系统。利用这种新的测量系统可以获得高质量的磁化强度数据，通过测量高场磁化强度的温度依赖性，可以得到NpRhGa_5的磁相图。在变磁一级跃迁时，磁各向异性约为 1 μ_B/Np 的磁矩转变为无磁各向异性的约 0.5 μ_B/Np 的小磁矩，低温态的基态由以下理论表示。 Kiss 和 Kuramoto 的四极相互作用意味着该系统可以用局域矩 5f 电子模型来解释。测量了振荡，结果表明 5f 电子是流动的。这些结果表明，该化合物的磁性不能用简单的局域或流动 f 电子模型来解释。NpO_2 的磁化强度始终低于 T_N。显示 5f 电子之间的反铁磁相互作用非常强。这些结果在国际会议、SCES05（维也纳）、Handai 论坛上得到了体现。 （河内）、ICM2006（京都）和 RHMF2006（仙台）这些结果也在 JPS 会议中得到体现。

项目成果

Magnetic properties of a transuranium compound NpRhGa_5

超铀化合物NpRhGa_5的磁性

• 发表时间: 2006
• 期刊: Frontiers of Basic Science : Towards New Physics-Earth and Spece Science-Mathematics (阪大出版会)
• 作者: K.Sugiyama;H.Nakashima;D.Aoki;S.Ikeda;Y.Haga;E.Yamamoto;A.Nakamura;Y.Homma;Y.Shiokawa;K.Kindo;M.Hagiwara;Y.Onuki;K.Umeo;杉山清寛;H.Kubo;Winfried Koller;K.Umeo;杉山清寛
• 通讯作者: 杉山清寛

High-field magnetization in transuranium compound

超铀化合物的高场磁化

• 发表时间: 2007
• 期刊: J. Magn. & Magn. Mater. 310
• 作者: 久保健;田中秀数;S. Niitaka;T. Nakano;F. Iga;S. Kimura;M. Hagiwara;S. Yoshii;N. D. Dung;N. V. Hieu;宮下精二;K. Sugiyama
• 通讯作者: K. Sugiyama