Study of quantum phenomena caused by multi-4f electrons

我们主要通过核磁共振测量研究了Yb、Sm、Eu和U基重费米子化合物，从而获得了关于这些化合物的局域对称性和磁场效应的重要信息。特别是i)阐明了YBCO_2Zn_(20)&Gt；Ii)为了研究Uru_2Si_2在17.5K时的相变(所谓的“隐序”)，我们介绍了一种利用核四极相互作用研究局域结构对称性的新方法。Iii)对于EuPtP，我们已经成功地确定了在伴随Eu价态变化的相变过程中体系的对称性如何变化。

We have studied Yb-, Sm-, Eu-, and U-based heavy fermion compounds mainly by Nuclear Magnetic Resonance(NMR) measurements, so that important information about local symmetries and magnetic field effects on these compounds have been obtained. Especially, i) We have clarified the mechanism of strong field effects in YbCo_2 Zn_<20>. ii) In order to study the phase transition(so called "hidden order") at 17.5 K in URu_2 Si_2, we have introduced a new method for investigating local structural symmetries via nuclear quadrupole interactions. iii) For EuPtP, we have succeeded in assigning how symmetries of the system change at the phase transitions accompanied by Eu valence changes.