Systematic studies of the anomalous changes of physical properties with punictogen elements in ternary rare-earth compounds

研究了三元稀土化合物CePtX（X=Sb，As，P，N）和CePdX（X=As，P，N）中致敏元素（X）对物性的影响。第二部分是制备EuPdSb和PrPtBi的单晶体，它们的多晶体显示出我们以前报道过的有趣的物理性质.首先，我们报道了这些化合物的晶体结构，发现CePtSb具有LiGaGe型晶体结构，而CePtAs和CePtP具有YPtAs型晶体结构.至于CePdX，CePdAs具有LiGaGe型，而CePdP具有BeZrSi型。遗憾的是，我们还没有成功地制备CePtN和CePdN。LiGaGe、YPtAs和BeZrSi都具有六方晶体结构，并且构成元素在单位晶胞中的位置几乎相同。因此，这些化合物是一个合适的一个系统的调查的X依赖性的物理性质。接下来，我们报告这些化合物的物理性质。CePtAs和CePtP都表现出非常强的各向异性的输运性质。我们还检测到dHvA效应的信号。对信号的分析表明，费米面为二维圆柱形，与输运性质一致。我们还观察到了CePdAs的dHvA效应，在磁性方面，发现CePtX的易磁化轴随着X从Sb → As → P的变化而连续地从c轴向c面变化。EuPdSb具有TiNiSi型晶体结构，我们成功地制备了单晶。通过对磁场和强场磁化下比热的详细研究，得到了EuPdSb的T-H相图。此外，我们观察到EuPdSb的dHvA效应。这是在TiNiSi型晶体结构中观察到的第一个dHvA信号。

The main purpose of the present research was to investigate the punictogen element (X) dependences of physical properties in ternary rare-earth compounds CePtX (X=Sb,As,P,N) and CePdX (X=As,P,N). The another one was to prepare single crystals of EuPdSb and PrPtBi, polycrystals of which show interesting physical properties as reported by us previously.Firstly, we report crystal structures of these compounds.It is found that CePtSb has a LiGaGe-type crystal structure, while CePtAs and CePtP have YPtAs type. As for CePdX, CePdAs has a LiGaGe-type, while CePdP has a BeZrSi-type. Unfortunately, we have not yet succeeded in preparing CePtN and CePdN.Both LiGaGe, YPtAs and BeZrSi have a hexagonal crystal structure and positions of the constituent elements in the unit cell is nearly the same. Therefore, these compounds is a suitable one for systematic investigation of the X dependences of the physical properties.Next, we report physical properties of these compounds.Both CePtAs and CePtP show very strong anisotropy of transport properties. We have also detected signals of the dHvA effect. From the analyses of the signal, it is found that the Fermi surface is of two-dimensional cylindrical shape, in agreement with the transport properties. We have also observed dHvA effect of CePdAs.As for the magnetic properties, it is found that the easy axis of magnetization of CePtX changes from c-axis to c-plane continuously as X changes fm Sb through As to P.EuPdSb has a TiNiSi-type crystal structure and we have succeeded in preparing single crystal. From the detailed studies of specific heat under the magnetic field and high-field magnetization, we obtained T-H phase diagram of EuPdSb. Furthermore, we observed dHvA effect of EuPdSb. This is the first dHvA signal observed in TiNiSi-type crystal structure.