STUDY OF DENSE KONDO COMPOUNDS WITH HIGH KONDO TEMPERATURE.

高近藤温度下的致密近藤化合物的研究。

基本信息

批准号：
61460036
负责人：
ISIKAWA Yosikazu
金额：
$ 3.97万
依托单位：
TOYAMA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1986
资助国家：
日本
起止时间：
1986 至 1987
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-61460036/
关键词：
Kondo effect dense Kondo compound heavy electron valence mixing intermediate valence Czochralski pulling method single crystal 単結晶【La_(1-x)】CexNi 電気抵抗低温比熱

项目摘要

We studied experimentally fundamental properties of La_<l-x>Ce_xNi where Ceni is a dense Kondo compound with a high Kondo temperature. Experimental results of electrical resistivity, lattice constants, magnetic susceptibility and specific heat reveal that the compound of CeNi is one of the dense Kondo compound with a high Kondo temperature although CeNi was heretofore called a mized valence compound. The Kondo temperature of the system La_<l-x>Ce_xNi changes continuously from 4 to 100K as the concentration of Ce atoms increases from zero to one.Motivated by the question whether the intermetallic compound SmCu_2 is a valence mixing compound, we have studied studied the magnetic, transport and thermal properties of SmCu_2 using a purified large single crystal. It is found from these experiments that the compound SmCu_2 is an antiferomagnet with the Neel temperature of 23K and that the temperature dependence of the anisotropic susceptibility is very well nalized on the basis of the modifed point charge model of Sm trivalent ions including the antiferromagntic exchange interaction. The magnetic entropy, however, was estimated to be 88% of Rln2. The mixed valence state at low temperatures is not denied yet.One of the main theme of this project is a sample preparation of purified single crystals of dense Kondo compounds and mixed valence compounds by a pulling mehod. Spending 80%of this Grant-in-aid for Scientific Research, we have purchased an oven for pulling single crystals. We have succeeded to pull single crystals of, for example, LaNi, CeNi, SmCu_2, LaInCu_2, CeInCu2 and SmInCu_2. A solid-state electro-transport method was used to purify LaNi and CeNi for the experiment of de haas-van Alphen effect, which must be done soon.

我们研究了LA__ <l-x> Ce_xni的实验基本特性，其中CENI是一种密集的近核化合物，具有较高的近核温度。电阻率，晶格常数，磁敏感性和比热的实验结果表明，CENI的化合物是密集的近核化合物之一，尽管CENI被称为估算化合物。随着CE原子的浓度从零升高到1，系统的围栏温度la_ <l-x> ce_xni从4持续变为100k。通过问题间的金属化合物SMCU_2是否是一种磁性，传输和热的smcu_ 2 cutifififififififififififified cliffified crystar。从这些实验中可以发现，化合物SMCU_2是一种抗fiferomagnet，NEEL温度为23K，并且根据SM Triverent离子的修饰点电荷模型，包括抗fiferromagntic交换互动。但是，磁熵估计为RLN2的88％。低温下的混合价状态尚未否认。该项目的主题之一是通过拉动Mehod的纯化的密集近托化合物和混合价化合物的纯化的单晶制备。我们花了80％的赠款进行科学研究，我们购买了一个用于拉动单晶的烤箱。我们已经成功地拉动了例如Lani，Ceni，Smcu_2，Laincu_2，Ceincu2和Smincu_2的单晶。使用固态电交易法来净化lani和ceni进行De Haas-Van Alphen效应的实验，这必须很快进行。