Effect of valence fluctuation in heavy fermion superconductors under pressure

本研究通过对单晶CeIrIn_5在压力下的物理性质测量，发现了量子临界点附近超导电性与反铁磁性之间关系的新信息，并从理论上指出了量子临界点附近原子价态的涨落。本文重点研究了Yb基重费米子化合物中量子临界压力最小的压致反铁磁体YbCo2Zn20。我们成功地制备了YbCo_2Zn_（20）单晶，并发现了其压力效应的新信息。

In this investigation, we found new information of the relationship between superconductivity and antiferromagnetism in vicinity of quantum critical point by means of the physical properties measurements under pressure of a single-crystalline CeIrIn5, in which it has been pointed out that valence fluctuation takes place near the quantum criticality point by theory,Next, we focus on a pressure-induced antiferromagnet YbCo2Zn20 with the smallest quantum critical pressure in Yb-based heavy fermion compounds. We succeeded in the single-crystalline doped YbCo2Zn20 and found new information of its pressure effect.