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Mechanism of disappearance of magnetic moment of Ni in relation with Rare Earths, especially with heavy fermion element of Ce

Ni的磁矩消失机制与稀土，特别是与Ce的重费米子元素的关系

基本信息

批准号：
20560618
负责人：
YANO Kazuo
金额：
$ 2.41万
依托单位：
Nihon University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2008
资助国家：
日本
起止时间：
2008 至 2010
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-20560618/
关键词：
磁性の発現機構微視的手法重い電子系電子・磁気物性ニッケル磁気モーメントの消失希土類元素セリウム CeNi パウリ・パラ (Ce-Gd)Ni 磁気秩序の発現 RKKY相互作用電子状態磁気的オーダー

项目摘要

In this study, we have aimed at making clear the electronic states of CeNi, which is one of the most famous "heavy fermion" compound systems, mainly from the view point of magnetic properties. It is well-known that the CeNi has no magnetic order and the Ni in CeNi is non-magnetic. On the other hand, the GdNi, which has the same crystal-structure as that of CeNi, is revealed to be a ferri-magnet and the Ni in GdNi does retain magnetic moment stemming from 3d electrons. It follows that in (Ce_<1-X>Gd_X) Ni system, the Ni is expected to change its electronic state (of 3d) from non-magnetic state to magnetic one according to the Gd content and the study of the transformation of this (3d) electronic state does give us important clues to understand the mechanism of appearance and disappearance of magnetism. Regarding to Ce, the same thing is expected.What we have carried out and found in these three years is summarized as follows ; (1) we have prepared 6 kinds of single crystals (Gd=0.03, 0.10, 0.15, 0.20, 0.50, 0.80), (2) we have measured magnetic properties for 6 contents of Gd and analyzed using molecular field analysis, (3) in Gd=0.03-0.20, the exchange interaction between Gd and Gd JGd-Gd i.e. RKKY interaction is considerably suppressed, (4) soft X-ray MCD measurement was carried out for Gd=0.8 at SPring-8 and some interesting results were obtained.

在本研究中，我们主要从磁性的角度来明确CeNi的电子态，CeNi是最著名的“重费米子”化合物体系之一。众所周知，CeNi是无磁序的，CeNi中的Ni是非磁性的。另一方面，GdNi具有与CeNi相同的晶体结构，是一个铁磁体，并且GdNi中的Ni确实保留了三维电子产生的磁矩。由此可见，在（Ce_<1-X>Gd_X） Ni体系中，根据Gd的含量，Ni的电子态（3d）有望从非磁性态转变为磁性态，对这种（3d）电子态转变的研究为我们理解磁性的出现和消失机理提供了重要线索。对于Ce，同样的事情是预期的。三年来我们的工作和发现总结如下：(1)制备了6种单晶（Gd=0.03、0.10、0.15、0.20、0.50、0.80）；(2)测定了6种Gd含量的磁性能，并进行了分子场分析；(3)在Gd=0.03-0.20时，Gd与Gd之间的交换相互作用JGd-Gd即RKKY相互作用被明显抑制；(4)在弹簧-8上对Gd=0.8进行了软x射线MCD测量，得到了一些有趣的结果。