Precize measurements of the transport propenties of f-electron ststem at low temperatures

低温下f电子体系输运特性的精确测量

基本信息

批准号：
09640442
负责人：
SATO Hideyuki
金额：
$ 2.3万
依托单位：
TOKYO METROPOLITAN UNIVERSITY
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

项目摘要

The Hall coefficient (R_H) and thermoelectric power (S) have been systematically investigated on f-electron compounds down to the He^3 temperature region. The lower temperature measurements using a dilution refrigerator have been also proceeded. Special emphasis were put on the materials exhibiting non-Fermi liquid anomalies which have been the systems of current interest in the field of f-electrons. In order to obtain reliable results, we have started from the high quality crystal growth for each system. For comparison with R_H and S, we also measured the resistivity (P), specific heat, and magnetic susceptibility.Y_<0.8>U_<0.2>Pd_3 : R_H shows a linear increase with decreasing temperature, which is slight1y strange as an ordinary magnetic systems. It can be understood, however, as due to the anomalous Hall effect, if we take into account the closeness of the concentration to the 0 K-spinglass transition.CeNi_2Ge_2 : R_H at high temperatures could be explained as due to the ordinary skew scattering, while R_H at low temperatures does not follow the relation, R_H * P^2, predicted from the Fermi liquid (FL) theory. It rather follows R_H * ln(p) in a wide temperature range. At this stage, however, we cannot conclude that the deviation from the FL prediction in R_H is directly related with the non-FL behaviors in the other properties.Y_<1-x>U_xRu_2Si_2, Th_<1-x>U_xRu_2Si_2 : These systems were the most probable candidates exhibiting anomalies originating from the two channel Kondo effect. Anomalous behaviors appear below a characteristic temperature (T_c). R_H was also found to exhibit an anomalous decrease below T_c, which is hardly explainable within the ordinary anomalous Hall effect. We also found S sharply decreases below T_c and shows a deep minimum at lower temperatures.CeFe_2Ge_2 : We found CeFe_2Ge_2 to be a new heavy Fermion metamagnet which shows anomalous transport properties, suggesting the non-FL behavior related with the spin fluctuation.

霍尔系数 (R_H) 和热电势 (S) 已在低至 He^3 温度范围的 f 电子化合物上进行了系统研究。使用稀释制冷机进行的较低温度测量也已进行。特别强调了表现出非费米液体异常的材料，这些材料是当前 f 电子领域感兴趣的系统。为了获得可靠的结果，我们从每个系统的高质量晶体生长开始。为了与R_H和S进行比较，我们还测量了电阻率（P）、比热和磁化率。Y_<0.8>U_<0.2>Pd_3：R_H随着温度的降低呈线性增加，这与普通磁性材料相比略有奇怪系统。然而，可以理解，由于反常霍尔效应，如果我们考虑到浓度与 0 K 自旋玻璃转变的接近程度。高温下的 CeNi_2Ge_2 : R_H 可以解释为由于普通的斜散射，而低温下的 R_H 并不遵循费米液体 (FL) 理论预测的关系 R_H * P^2。它在很宽的温度范围内遵循 R_H * ln(p)。然而，在现阶段，我们不能得出结论，R_H 中 FL 预测的偏差与其他属性中的非 FL 行为直接相关。Y_<1-x>U_xRu_2Si_2、Th_<1-x>U_xRu_2Si_2 ：这些系统是最有可能表现出源自两通道近藤效应的异常现象的候选者。异常行为出现在特征温度 (T_c) 以下。还发现 R_H 在低于 T_c 时表现出异常下降，这在普通的异常霍尔效应中很难解释。我们还发现 S 在低于 T_c 时急剧下降，并在较低温度下显示出较深的最小值。 CeFe_2Ge_2 ：我们发现 CeFe_2Ge_2 是一种新的重费米子超磁体，它表现出异常的输运特性，表明与自旋波动相关的非 FL 行为。