Rltralow-Temperature Properties manifested by Nuclei and electrons in Praseodimium Compounds

1) Hata等发现PrCu_6中核自旋的倾斜结构和prptal中电子矩的倾斜顺序在2.15mK以下。注意到该化合物的单晶斜晶结构，在单晶胞中有两个不相等的原子位，我们推导了Dzyaloshinky-Moriya型RKKY相互作用，并讨论了实验结果。接下来，我们研究了Kitazawa等人在5.8K以下发现的PrPtAl中的倾斜电磁学。这种倾斜序是由范维克磁化率张量的主轴在单元胞中两个不相等的原子位置上彼此不同引起的。2) PrPb_3中的反铁四极有序（AEQO）和核自旋有序PrPb_3具有立方结构，其中建立了Γ_3双重态基态。电子四极矩与Γ_3态有关。在0.4K以下，已知发生AFQO。Kawae等人表明，当La取代Pr仅2%时，AFQO被破坏，对于更浓的样品出现t -线性比热。局部电场受到La的强烈干扰。我们应用这一理论讨论了玻璃两能级系统的比热。进一步，我们从理论上研究了AFQO状态的性质，发现存在两种不同对称性的解。研究了AEQO下的核自旋顺序。发现核自旋交替排列形成两种AF结构。3)我们写了一篇关于Van Vleck金属的核磁性的综述文章，描述了该研究从早期开始到最近的发展。

1)Canted spin structures of nuclear spins in PrCu_6 and of electronic moments in PrPtAlCanted nuclear spin order in PrCu_6 was found below 2.15mK by Hata et al. Noting the monoclinic crystal structure of this compound in which there are two non-equivalent atomic sites in the unit cell, we derived the Dzyaloshinky-Moriya type RKKY interaction and discussed the experimental result. Next we studied the canted electronic magnetism in PrPtAl below 5.8K found by Kitazawa et al. The canted order is brought by the fact that the principal axes of the Van Vieck susceptibility tensors differ each other at the two non-equivalent atomic sites in the unit cell.2)Antiferro-Quadrupolar Ordering (AEQO) in PrPb_3 and Nuclear spin orderPrPb_3 has a cubic structure, in which the Γ_3 doublet ground state is established. Electronic quadrupolar moment is associated with the Γ_3 state. Below 0.4K it is known that the AFQO occurs. Kawae et al. showed that when La is substitued for Pr only by 2% the AFQO is destroyed and for more concentrated samples T-linear specific heat appears. The local electric field is strongly disturbed by La. We discussed the specific heat by applying the theory for the two level system in glasses. Further, we have studied theoretically the nature of the AFQO state and found that there exist two types of solutions with different symmetries. The nuclear spin order under the AEQO has been studied. It is found that the nuclear spins arrange alternately to form two types of AF structures.3)We wrote a review article on the nuclear magnetism of the Van Vleck metals, which describes the development of the study from its early begginigs to its recent developments.