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

人们已经系统地研究了f电子化合物的霍尔系数（R_H）和热电势（S），直到He^3温度区。利用稀释制冷机进行了低温测量。特别强调的材料表现出非费米液体异常，一直是当前感兴趣的f-电子领域的系统。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，发现Y_<0.8>U_<0.2>Pd_3：R_H随温度的降低呈线性增加，这与一般的磁性系统略有不同。但是，如果考虑到浓度与0 K-自旋玻璃转变的接近程度，则可以将其理解为反常霍尔效应的结果。高温下的CeNi_2Ge_2：R_H可以解释为普通的斜散射，而低温下的R_H不遵循费米液体（FL）理论预测的关系式R_H * P^2。它在很宽的温度范围内遵循R_H * ln（p）。在目前的研究阶段，我们还不能得出这样的结论：R_H偏离FL预测与其它性质的非FL行为有直接关系。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双通道Kondo效应异常的候选系统。在特征温度T_c以下出现反常行为。在T_c以下，R_H也出现了反常的下降，这在一般的反常霍尔效应中是很难解释的。CeFe_2Ge_2：我们发现CeFe_2Ge_2是一种新的重费米子超磁体，它具有反常的输运性质，表明其非FL行为与自旋涨落有关。

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.