Study of the Physical Properties of Narrow and Direct f band.

1991-1992年，作为一个为期两年的项目，开始了题为“窄直f带物理性质的研究”的研究。1991年，我们用光脉冲法建立了比热测量装置，然后制备了单晶，以进行1992年计划的研究。另一方面，近两年来，对f电子体系的研究取得了很大进展，人们认为，“价涨落”这一令人联想到动力学性质的术语不仅不适合于金属化合物，而且也不适合于绝缘价涨落化合物。换句话说，原子价涨落区的基态，这一直被认为是属于窄的和直接的f-带的现象，是本项目的一个主题，可以很好地描述正常的能带计算。我们对YbB_3<12>和Ce_3（Au_<1-x>Pt_x）_3Sb_4的研究无疑对这一结论作出了贡献。在此背景下，本文提出了一个新的问题， ...更多信息 提出了用能带计算能否解释反常铁磁价涨落化合物CeRh_3B_2和UIr_3B_2的问题。研究结果如下：1）Ce_3（Au_<1-x>Pt_x）_3Sb_4的价态涨落。Pt取代Au减少了一个电子，导致Ce的价态从3+向4+移动，并在Ce 3 Pt 3Sb 4中形成价态起伏。在这个过程中，半导体性质持续存在。这意味着能隙是由带隙引起的。2）高压下YbB_2的输运<12>。我们已经测量了晶格参数和能隙的压力依赖性。发现YbB_3和SmB_6中能隙为零时晶格参数的相对位移相同<12>。3）用软X射线线性二向色性研究CeRh_3B_2中的巨晶场和铁磁性。4）用软X射线线性二向色性研究Fe掺杂的UIr_3B_2中的磁性。Ir的5d带被Fe磁矩极化，通过f-d杂化而呈现铁磁性。少

As a two-years(1991-1992) project, the research of title "Study of the Physical Properties of Narrow and Direct f band" started. In 1991, we built up apparatus of specific-heat measurement by using the light-pulse method and then prepared single crystal to perform the study planned in 1992. On the other hand, within these two years, study of so-called f electron system make great progress, and it is now believed that the terminology "Valence Fluctuation" which reminds of dynamical properties is not appropriate expression not only for metallic but also for insulating valence fluctuation compounds. In other words, ground state of valence fluctuating regime which has been believed to belong to phenomena in narrow and direct f-band and was a main theme in this project can be fairly well described by normal band calculation. Needless to say, our studies on YbB_<12> and Ce_3(Au_<1-x>Pt_x)_3Sb_4 contribute much to this conclusion. On the basis of these background, new aspect of a question tha … More t whether or not the anomalous ferromagnetic valence fluctuating compound CeRh_3B_2 and UIr_3B_2 can also be explained by the band calculation arises. The results of our research are as follows.1) Valence fluctuating state of Ce_3(Au_<1-x>Pt_x)_3Sb_4... Pt substitution for Au decreases one electron, resulting in the shift of Ce valence from 3+ to 4+ and valence fluctuating state in Ce_3Pt_3Sb_4. In this process, semiconducting property persists. This implies that the energy gap arises from the band gap.2) Transport of YbB_<12> under high pressure... We have measured pressure dependencies of the lattice parameter and energy gap. We have found that relative shift of lattice parameter at which energy gap becomes zero is the same in YbB_<12> and SmB_6.3) Study of the giant crystalline field and ferromagnetism in CeRh_3B_2 via Soft-X-ray linear-dichroism.4) Study of the magnetic property in Fe-doped UIr_3B_2... 5d band of Ir are polarized by Fe-moment and then ferromagnetism is appeared via f-d hybridization. Less