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

作为一个为期两年(1991-1992)的课题，“窄直f带物理性质的研究”开始了研究工作。1991年，我们利用光脉冲法建立了比热测量装置，并制备了单晶用于1992年计划的研究。另一方面，在这两年里，对f电子系统的研究取得了很大的进展，现在人们认为“价涨落”这个提醒动力学性质的术语不仅适用于金属，而且也适用于绝缘价涨落化合物。换言之，价起伏体系的基态被认为属于窄而直接的f带现象，也是本项目的一个主要主题，它可以用正常带计算得到相当好的描述。不用说，我们对YbB_(12)&gt；和Ce_3(Au_&lt；1-x&gt；Pt_x)_3Sb_4的研究对这一结论有很大贡献。在这些背景的基础上，一个问题的新方面THA…此外，反常的铁磁价波动化合物CeRh_3B_2和UIr_3B_2是否也可以用能带计算来解释。研究结果如下：1)Ce_3(Au_&lt；1-x&gt；Pt_x)_3Sb_4…Pt取代Au减少了一个电子，导致Ce的价态从3+向4+转变，Ce_3Pt_3Sb_4的价态发生了起伏。在这个过程中，半导体性质仍然存在。这意味着能隙是由YBB_12&GT；在高压下的输运带隙引起的。我们测量了晶格参数和能隙的压力依赖关系。用软X射线线性二色性方法研究了CeRh_3B_2的巨晶场和铁磁性。4)研究了掺Fe的UIr_3B_2的磁性。铁矩使Ir的5维能带极化，通过f-d杂化产生铁磁性。较少

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