DUALITY OF LOCALISED AND DE-LOCALIZED CHARACTERS OF 4F ELECTRONS IN CERIUM COMPOUNDS

铈化合物中 4F 电子的局域和离域特征的二重性

基本信息

批准号：
11640342
负责人：
ISIKAWA Yosikazu
金额：
$ 2.3万
依托单位：
Toyama University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11640342/
关键词：
Cerium compound 4f electrons localization Kondo effect heavy electrons magnetic susceptibility Valence fluctuation single crystal

项目摘要

The intermetallic compound CePdAl is a typical example to study intermediate characters between localization and de-localization of 4felectrons in the cerium compound. However, there was not good sample with a residual resistibility less than a few mΩcm when the experiments started on this samples. We have focused on this sample and concentrated ourselves to grow good single-crystalline samples. We have succeeded to prepare a single crystal with 20μΩcm, and it drops a few μΩcm under magnetic fields, suggesting a possibility to detect the de Haas-van Alphen oscillations. Main results obtained here are as follows:1. Single crystalline samples of C (Pd_<1-x>Ni_x)Al have been successfully prepared, where x ranges from 0.0 to 1.0.2. The electrical resistibility, magnetic susceptibility, and specific heat experiments have been carried out under the extreme conditions, the lowest temperature 0.1K, the maximum pressure 1.3 GPa and the highest field 15 T. From these experimental results, it is found that (1) the Neel temperature smoothly decreases and disappears as the pressure increases, (2) at the same time the magnetization of 4f electrons diminishes. These results are consistent with those of the instituted systems of Ce(Pd_<1-x>Ni_x)Al.3. The temperature dependence of the electrical resistibility shows non-Fermi liquid behaviors as T^<1.5> down to 0.1K. But this character collapses under the magnetic field 7T, and a Fermi liquid behavior revives, i.e., ρ〜T^2.4. The thermoelectric power of single crystalline samples of Ce(Pd_<1-x>Ni_x)Al shows huge positive value around 100 K in x 〜 0.4 far different from the critical concentration x_e 〜 0.1, and the initial slope dS/dT at low temperatures also makes a maximum at x 〜 0.4.

金属间化合物cepdal是研究4FEECTRON在岩岩化合物中的定位和除外定位之间的中间特征的典型例子。但是，当实验在该样品上开始时，没有小于几个MΩCM的剩余耐药性的好样品。我们专注于该样品，并集中精力生长良好的单晶样品。我们已经成功地准备了一个具有20μCM的单晶，并且在磁场下掉落了几个μΩCM，这表明有可能检测De Haas-Van Alphen振荡。这里获得的主要结果如下：1。 C（pd_ <1-x> ni_x）Al的单晶样品已成功制备，其中x范围为0.0至1.0.2。 The electrical resistibility, magnetic susceptibility, and specific heat experiments have been carried out under the extreme conditions, the lowest temperature 0.1K, the maximum pressure 1.3 GPa and the highest field 15 T. From these experimental results, it is found that (1) the Neel temperature smoothly decreases and disappears as the pressure increase, (2) at the same time the magnetization of 4f electronics diminishes.这些结果与CE（PD_ <1-X> ni_x）Al.3的建立系统的结果一致。电阻性的温度依赖性表明非Fermi液体行为为T^<1.5>下降至0.1K。但是该特征在磁场7T下崩溃，而费米液体行为恢复了，即ρ〜T^2.4。 CE（PD_ <1-X> ni_x）的单晶样品的热电功率在X〜0.4中显示出巨大的正值，与临界浓度x_e〜0.1差异很大，并且在低温下的初始斜率DS/DT也使最大值在x〜0.4处也使得最大。