The Study of Fermi Surfaces of the Intermetallic Compounds Between Rare-Earths and Nickel

利用de Haas-van Alphen （dHvA）效应和高磁场磁阻研究了CeNi和其他稀土-镍化合物的费米表面。CeNi是一种混合价态材料，其f电子可以被认为与传导电子发生强烈杂化而变得流动。我们成功地用Czochralski法和固态电输运法生长出了高质量的单晶。实验结果表明，LaNi的费米面包含两个沿b轴和c轴伸长的开放面。在基面上发现了许多频率在0.7 ~ 150 MG之间的dHvA分支。在CeNi中，开放轨道与LaNi一样沿b轴和c轴存在。沿b轴发现了四个dHvA分支，沿a轴发现了两个分支。CeNi的回旋加速器质量大约是LaNi的十倍。从这些结果以及与带计算的比较，可以得出f电子是流动的。另一方面，PrNi和NdNi的磁电阻行为不同于LaNi和CeNi，因为它们没有沿c轴的开放轨道。在PrNi中观察到许多频率在2mg到40mg之间的dHvA分支。沿b轴的频率分别为4.3 MG和1.3 MG，有效质量分别为2.2 m_0和1.06 m_0。这些值与LaNi中的值相同。与LaNi的明显区别是存在以a轴为中心的低频分支。基于铁磁有序的影响，讨论了这种与LaNi的区别。

The Fermi surfaces of the CeNi and other rare earth-nickel compounds have been investigated by means of de Haas-van Alphen (dHvA) effect and high field magnetoresistance. CeNi is characterized as a mixed valence material, and the f electron could be considered to strongly hybridize to the conduction electrons and becomes itinerant. We have successfully grown the high quality single crystals by a Czochralski method and a solid-state electro-transport method.As the experimental results, the Fermi surface of LaNi contains two open surfaces elongated along the b- and c-axes. Many dHvA branches with the frequencies ranged from 0.7 MG to 150 MG were found in the fundamental planes. In CeNi, the open orbits exist along the b- and c-axes as same as LaNi. Four dHvA branches have been found along the b-axis and two branches along the a-axis. The cyclotron masses of CeNi are about ten times heavier than those of LaNi. From these results and the comparison with a band calculation, it was concluded that the f electron is itinerant.On the other hand, the behaviors of the magnetoresistance in PrNi and NdNi are different from LaNi and CeNi, because of the absence of an open orbit along the c-axis. Many dHvA branches with the frequencies ranged from 2 MG to 40 MG have been observed in PrNi. The frequencies along the b-axis are 4.3 MG and 1.3 MG and the effective masses are 2.2 m_0 and 1.06 m_0, respectively. These values are the same as that in LaNi. The obvious difference from LaNi is the presence of branches with low frequencies, being centered at the a-axis. This difference from LaNi was discussed based on the effect of a ferromagnetic ordering.