de Haas-van Alphen Effect in the Heavy Fermion Compound with Amplitude-Modulated Magnetic Structure

调幅磁结构重费米子化合物中的德哈斯-范阿尔芬效应

• 批准号: 09640425
• 负责人: ISIKAWA Yoshikazu
• 金额: $ 1.98万
• 依托单位: Toyama University, Faculty of Science
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09640425/
• 关键词: amplitude-modulated magnetic structure; heavy Fermion; de Hass-van Alphen effect; Kondo effect; magnetoresistance; non-localization; compensated metal

(1) Studies of de Haas-van Aiphen Effect and Fermi Surfaces of LaNi_2Al_5 :Magnetoresistance and de Haas-van Alphen measurements have been performed to investigate Fermi-surface property of LaNi_2AI_5, which is a reference material of a magnetic dense-Kondo compound CeNi_2AI_5. Thirteen branches with the frequencies from 1.25x10^6 to 101 x10^6 Oe have been observed in the angular-resolved dHvA measurements, and the magnetoresistance shows the existence of open orbits. The results are well explained by the Fermi surfaces obtainedfrom an FLAPW band-structure calculation.(2) Studies of de Haas-van Alphen Effect and Fermi Surfaces of Magnetic Dense-Kondo Compound CeNi_2AI_5 :The experiments of de Haas-van Aiphen (dHvA) effect have been carried out at temperatures down to 40 mK in CeNi_2AI_5 with an incommensurate magnetic structure. A complex phase diagram of the magnetic transition field versus temperature is completed. Many branches of the dHvA frequencies observed in the higher-field regions, II, Ill and IV, have been understood by the branches predicted from the theoretical Fermi surfaces of nonmagnetic reference-sample LaNi_2AI_5 better rather than the theoretical ones in CeNi_2AI_5 with 4f electrons treated as itinerant. Branches observed in the lowest field region I are not clearly analyzed with the theoretical prediction in LaNi_2AI_5 or CeNi_2AI_5, The electrons with heavy cyclotron mass are observed in the region IV ; 12.4 m_0 in eta branch, 11.2 m_0 in zeta branch and 9.6 m_0 in theta branch. Some pairs of parallel branches are observed due to the spin-splitting related to the magnetism, and the exchange energy DELTA E is obtained ; DELTA E=12.9 meV in beta branch and 7.8 meV in delta branch. The relations between the Fermi surfaces and the magnetic structure are discussed.

(1) LaNi_2AI_5的de Haas-van Aiphen效应和费米表面研究：采用磁电阻和de Haas-van Alphen测量方法研究了LaNi_2AI_5的费米表面性质，LaNi_2AI_5是磁性致密化合物CeNi_2AI_5的参考材料。在角分辨dHvA测量中观测到频率在1.25x10^6到101 x10^6 Oe之间的13个分支，磁电阻显示了开放轨道的存在。从FLAPW波段结构计算中得到的费米曲面很好地解释了这一结果。(2)磁性致密化合物CeNi_2AI_5的de Haas-van Aiphen效应和费米表面的研究：在具有不对称磁性结构的CeNi_2AI_5中，在低至40 mK的温度下进行了de Haas-van Aiphen （dHvA）效应的实验。完成了磁场随温度变化的复杂相图。从非磁性参考样品LaNi_2AI_5的理论费米面预测的分支可以更好地理解在高场区（II， Ill和IV）中观测到的dHvA频率的许多分支，而不是将4f电子视为流动的CeNi_2AI_5中的理论分支。在LaNi_2AI_5或CeNi_2AI_5中，在最低场区I观察到的分支不能用理论预测清楚地分析，在IV区观察到具有重回旋质量的电子；分支为12.4 m_0，分支为11.2 m_0，分支为9.6 m_0。由于与磁性有关的自旋分裂，观察到一些平行分支对，并得到了交换能DELTA E；δ E= β支12.9 meV， δ支7.8 meV。讨论了费米表面与磁性结构之间的关系。

项目成果

J.X.Boucherle: "Crystal electric field effects on the magnetic form factor of the Kondo compound CeNi_2Al_5" Physica B. 234-236. 875-876 (1997)

J.X.Boucherle：“晶体电场对近藤化合物 CeNi_2Al_5 磁性形状因子的影响”Physica B. 234-236。

桑井智彦: "CeNi2Al5の極低温磁気熱量効果" 低温だより(富山大学低温液化室)vol.11. 印刷中.

Tomohiko Kuwai：“CeNi2Al5 的低温磁热效应”低温通讯（富山大学低温液化实验室）第 11 卷现已印刷。

赤丸悟士: "CeNi_2Al_5とLaNi_2Al_5の磁気抵抗とCeの4f電子の非局在性について" 「強相関電子系の物理」平成9年度科研費研究成果報告書. IV. 31-34 (1998)

Satoshi Akamaru：“关于CeNi_2Al_5和LaNi_2Al_5的磁阻以及Ce中4f电子的离域”“强相关电子系统的物理学”1997年科学研究报告31-34（1998）。

Kunihiko Maezawa, Satoshi Akamaru, Tomohiko Kuwai, Yosikazu Isikawa, Junji Sakurai and Hisatomo Harima: "de Haas-van Alphen Effect and Fermi Surfaces of LaNi_2Al_5" submitted to J.Phys.Soc.Jpn.(1999)

Kunihiko Maezawa、Satoshi Akamaru、Tomohiko Kuwai、Yosikazu Isikawa、Junji Sakurai 和 Hisatomo Harima：“de Haas-van Alphen Effect and Fermi Surfaces of LaNi_2Al_5” 提交给 J.Phys.Soc.Jpn.(1999)

Yosikazu Isikawa, Hideto Takagi, Akiko Ishiguro, Masanari Yasumoto, Tomohiko Kuwai, Toshio Mizushima, Junji Sakurai, Anju Sawada, Takemi Komatsubara, Kunihiko Maezawa and Hisatomo Harima: "de Haas-van Alphen Effect and Fermi Surfaces of Magnetic Dense-Kon

Yosikazu Isikawa、Hideto Takagi、Akiko Ishiguro、Masanari Yasumoto、Tomohiko Kuwai、Toshio Mizushima、Junji Sakurai、Anju Sawada、Takemi Komatsubara、Kunihiko Maezawa 和 Hisatomo Harima：“德哈斯-范阿尔芬效应和磁致密-Kon 的费米面