New Development of the Quadrupole Interaction studied by Thulium Hexaboride (TmB_6)

六硼化铥(TmB_6)四极相互作用研究新进展

• 批准号: 11640330
• 负责人: KUNII Satoru
• 金额: $ 2.56万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11640330/
• 关键词: Quadrupole interaction; Thulium hexaboride; Rare-earth hexaboride; ツリウム-ヘキサボライド; セリウム・ヘキサボライド; 高濃度近藤効果; 重フェルミオン

The purpose of this research project is to elucidate the essential nature of quadrupole interactions in which many researchers are interested in recently. One of the interested materials in this research area is CeB_6 that is investigated by us for long years. CeB_6 has only one 4f electron that is the origin of the quadrupode interactions. On the other hand, Tm has 13-4f electrons, then TmB_6 is counterpart to CeB_6 because 4f shell is full for 14 electrons. Therefore, the quadrupole nature of TmB_6 is very important research subject. However, TmB_6 is not found its phase in room temperature and in normal pressure. We found a method to break the bottleneck of this problem. In CeB_6, the Kondo-type singlet-ion nature is not changed by substitution of Ce by La. On the contrary, many new informations appeared in the investigations of Ce_xLa_<1-x>B_6 by the substitution. We succeeded to grow good quality of single crystals of Tm_xLa_<1-x>B_6, Tm_xYb_<1-x>B_6 by floating zone method. They shows phase transition at 7.5 K for Tm_xYb_<1-x>B_6 and at 4.5 K for Tm_xLa_<1-x>B_6 by the electrical resistivity and the magnetization measurements. It is hard to consider the magnetic order at these phase transitions because Tm is contained by only 25%. The phase transitions are thought to be attributed to quadrupole interactions. Therefore, many other measurements of specific heat, neutron scattering, etc. are needed now.

该研究项目的目的是阐明最近许多研究人员感兴趣的四极相互作用的本质。 CeB_6是该研究领域感兴趣的材料之一，我们对其进行了多年的研究。 CeB_6 只有一个 4f 电子，这是四极相互作用的起源。另一方面，Tm 有 13-4f 电子，则 TmB_6 与 CeB_6 对应，因为 4f 壳层充满了 14 个电子。因此，TmB_6的四极性质是非常重要的研究课题。然而，TmB_6在室温和常压下没有发现其相。我们找到了打破这个问题瓶颈的方法。在CeB_6中，Ce被La取代并没有改变近藤型单线态离子的性质。相反，在Ce_xLa_<1-x>B_6的研究中出现了许多新的信息。采用浮区法成功生长出优质的Tm_xLa_<1-x>B_6、Tm_xYb_<1-x>B_6单晶。通过电阻率和磁化强度测量，它们显示了 Tm_xYb_<1-x>B_6 在 7.5 K 处的相变以及 Tm_xLa_<1-x>B_6 在 4.5 K 处的相变。很难考虑这些相变时的磁序，因为 Tm 仅包含 25%。相变被认为归因于四极相互作用。因此，现在需要对比热、中子散射等进行许多其他测量。

项目成果

S.Kunii: "Phonon structure and specific heat analyses of rare-earth hexaborides"J.Solid State Chemistry. 154. 275-279 (2000)

S.Kunii：“稀土六硼化物的声子结构和比热分析”J.Solid State Chemistry。

T.Sakai, G.Oomi, Y.Uwatoko, S.Kunii: "Anomalous magnetoelastic properties of DyB_6 under high pressure."Physica B. 281&282. 588-590 (2000)

T.Sakai、G.Oomi、Y.Uwatoko、S.Kunii：“DyB_6 在高压下的反常磁致弹性特性。”Physica B. 281

N.E.Sluchanko, V.V.Glushkov, B.P.Gorshunov, S.V.Demishev, M.V.Kondrin, A.A.Pronin, A.A.Volkov, Y.Bruynseraede, V.V.Moshchalkov, S.Kunii: "The origin of the fast valence fluctuations in SmB_6."Physica B. 284-288. 1355-1356 (2000)

N.E.Sluchanko、V.V.Glushkov、B.P.Gorshunov、S.V.Demishev、M.V.Kondrin、A.A.Pronin、A.A.Volkov、Y.Bruynseraede、V.V.Moshchalkov、S.Kunii：“SmB_6 中快速价态波动的起源。”Physica B. 284-288

M.Sera: "Crystalline Electric Field Ground State of NdB_6"JJAP Series. 11. 191-193 (1999)

M.Sera：“NdB_6的晶体电场基态”JJAP系列。

N.E.Sluchanko, V.V.Glushkov, B.P.Gorshunov, S.V.Demishev, M.V.Kondrin, A.Pronin, A.A.Volkov, A.K.Savchenko, G.Gruner, Y.Bruynseraede, V.V.Moshchalkov, S.Kunii: "Intra-gap states in SmB_6."Phys.Rev.B. 61. 9906-9909 (2000)

N.E.Sluchanko、V.V.Glushkov、B.P.Gorshunov、S.V.Demishev、M.V.Kondrin、A.Pronin、A.A.Volkov、A.K.Savchenko、G.Gruner、Y.Bruynseraede、V.V.Moshchalkov、S.Kunii：“SmB_6 中的带隙内状态。”