权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Magnetic Phase Transitions fo Rare Earth Compounds Studied by the de Haas-van Alphen Effect

通过德哈斯-范阿尔芬效应研究稀土化合物的磁相变

基本信息

批准号：
04452034
负责人：
YOSHICHIKA Onuki
金额：
$ 3.46万
依托单位：
Osaka University (1994)University of Tsukuba (1992-1993)
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1994
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04452034/
关键词：
de Haas van Alphen effect magnetic transiton Fermi surface cyclotron mass rare earth compound Heavy fermion サイクロトロン有効質量メタ磁性 CeRu_2Si_2 散乱の緩和時間反強磁性 TbIn_3

项目摘要

The de Haas-van Alphen (dHvA) effect is the most useful method to determine the Fermi surface, cyclotron mass and scattering lifetime of the conduction electron. We have grown high-purity single crystals and studied the magnetic phase transitions of the rare earth compound by the dhvA method. We have found three kinds of phase transitions. Experimental results are as follow ;(1) Metamagnetic transition in the antiferromagnetic compoundWe have studied the dhvA effect of the antiferromagnetic compound NdIn_3. The Fermi surface in the antiferromagnetic state is found to be constructed by the band folding procedure of the Fermi surface of LaIn_3 into the small Brillouin zone based on the large magnetic unit cell.(2) Metamagnetic transition based on the quadrupole moment in PrCu_2We have found a new type of metamagnetic transition in PrCu_2 when the field is directed along the c-axis of the orthorhombic structure. Here, PrCu_2 is not an antiferromagnetic compound but a Van-Vlec para-magnetic compound with the singlet ground state of the 4f level. This transition brings about the switching of the easy (a-axis) and hard (c-axis) axs in magnetization.Change of the 4f electron nature from itinerant to localized in CeRu_2Si_2The metamagnetic behavior is found at 8T in CeRu_2Si_2 when the field is directed along the [001] direction in the tetragonal structure. We have studied in detail the dHvA experiments in fields up to 19T and at temperatures down to 20mK and clarified the Fermi surface. the 4f-electron is found to be changed in nature from itinerant to localized.

De Haas-van Alphen(DHvA)效应是确定传导电子的费米表面、回旋质量和散射寿命的最有用的方法。我们生长了高纯单晶，并用dhvA方法研究了稀土化合物的磁性相变。我们发现了三种相变。研究了反铁磁性化合物NdIn_3的dhvA效应，发现反铁磁态下的费米面是由LaIn_3的费米面在大的磁晶胞的基础上折叠成小的布里渊区而形成的。(2)基于PrCu2WE的四极矩的亚磁相变发现了一种新的沿斜方结构c轴方向的磁场作用下PrCu2的亚磁相变。这里，PrCu2不是反铁磁性化合物，而是单重态为4f能级的Van-Vlec顺磁化合物。这种转变导致了易(a轴)和硬(c轴)轴在磁化过程中的转换。在CeU_2Si_2中，4f电子的性质从巡游转变为定域。当磁场沿四方结构中的[001]方向时，在CeU_2Si_2中发现了8T处的亚磁行为。我们已经详细地研究了在19T和20mK温度下的dHvA实验，并澄清了费米面。发现4f电子在性质上由巡游电子转变为定域电子。