A Searching Study of New Heavy-Fermion Systems

新型重费米子系统的探索研究

• 批准号: 03044101
• 负责人: FUJII Hironobu
• 金额: $ 3.84万
• 依托单位: HIROSHIMA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for international Scientific Research
• 财政年份: 1991
• 资助国家: 日本
• 起止时间: 1991 至 1992
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03044101/
• 关键词: Heavy-Fermion; Ce Compound; U Compound; Searching Study; Transport Properties; Thermal Properties; Crystal Growth; Fermiology; 価類揺動; 電気伝導度; 比熱; ド・ハ-ス・ファン・アルフェン効果

In Monbusho International Scientific Research Program, we planned to make a searching study of new heavy-fermion systems in between Japan (Hiroshima Univ. and Tohoku Univ.) and Netherlands (Univ. of Amsterdam and Univ. of Leiden). In this course, we have found that some cerium and uranium intermetallic compounds display several interesting physical properties as Kondo-lattice ground states, depending on the degree of hybridizations of f-electrons with ligand s, p or d-electron states. The searching study has been independently performed in every university, keeping in close contact with each other. The results obtained are summarized as follows :(1) In Hiroshima Univ., ternary compounds UCu_2Sn (hexagonal ZrPt_2Al-type structure) and UAu_2Al (orthorhombic YPd_2Si-type one) has been found to undergo antiferromagnetism below 17 and 25K and to reach electronicspecific heat coefficient gamma-60 and 102 mJ / mole・K^2, respectively, indicating intermediate heavy-electron states. Furthermore, … More we found that UCu_<3+x>Ga_<2-x> exhibit a maximum of T_N=17K at x=0.3 and a nonmagnetic heavy-fermion state evolves with further increase in x (gamma reaches 460 mJ/mole・K^2 at x=0.6). (2) Tohoku Univ. group have found a heavy-electronic character in U_2PtSi_3 (hexagonal AlB_2-type) with gamma-200 mJ/K^2・mole and an itenerant feromagnetic phase. (3) In Univ. of Leiden, psudo-ternaries U_3Ni_3Sn_<4-x>Sb_X have been found to indicate that the intermediate region with relatively low carriers is in a much heavier fermion state than the end member with x=0 (usual carrior).Another aim in this project is to make single crystals of typical heavv-fermions and to perform systematic studies using them. As a typical material, we have focused on CeNiSn with a small-semiconducting energy gap in the Kondo-lattice ground state. Prof. Takabatake has grown its single crystal under the direction of Prof. Menovsky and measured the thermal expansion with Dr. de Visser in Amsterdam Univ. The result indicated that both alpha_a and alpha_b sharply decrease below 7K accompanied by the opening of an anisotropic energy gap. The neutron scattering experiments on CeNiSn are now in progress. Dr. Satoh has grown a single crystal of typical superconducting material UPd_2Al_3 and systematically studying the physical properties now.In last September. we held the Workshop on transport and thermal properties of felectron systems in Hiroshima and could intenively discuss their mutual interesting problems within our collaboration groups. Finally, we agreed with a proposal keeping in close contact within our groups concerning heavy-fermion problems even after finishing this project. Less

在Monbusho国际科学研究计划中，我们计划对日本（Hiroshima Univ。和Tohoku Univ。）和荷兰（阿姆斯特丹大学和莱顿大学）之间的新繁重特征系统进行搜索研究。在本课程中，我们发现某些葡萄和铀间金属化合物表现出一些有趣的物理特性，例如亲to-lattice基态，这取决于具有配体S，P或D电子状态的F-电子的杂交程度。搜索研究在每所大学都独立执行，并保持彼此密切联系。所获得的结果总结如下：（1）在广岛大学中，三元化合物UCU_2SN（六角形ZRPT_2Al-Type结构）和UAU_2AL（Orthorhombic YPD_2Si-Type One）已被发现，已被发现抗抗激素和25k，以下是Antifermagnet-priconific and and and and and and and and and and and 25k-25 kenmant and and and 25k 102 MJ / mole ・ k^2，表明中间重型电子状态。此外，…更多，我们发现ucu_ <3+x> ga__ <2-x>在x = 0.3时表现出最大的t_n = 17k，而非磁性重铁状态状态随着x的进一步增加（gamma达到460 mj/mole mole ・ k^k^k^2 in x = 0.6）。 （2）Tohoku Univ。组在U_2PTSI_3（六角形ALB_2-TYPE）中找到了一个重型电源特征，该特征具有gamma-200 mj/k^2 r​​和iTenerant thererant theragnation agnerant agmagnetic阶段。 （3）在大学。在莱顿（Leiden）的psudo-ternaries u_3ni_3sn_ <4-x> sb_x已发现表明，载体相对较低的中间区域比x = 0的最终成员更重的费米，而（通常的载体）。在这个项目中，该项目的另一个目标是使典型的重型verve feferve-fightip forge foremical heverver of典型的重型研究对他们进行系统和系统的表演。作为一种典型的材料，我们专注于在亲to的基础状态下具有小型导向器能量隙的Cenisn。高塔克（Takabatake）教授在Menovsky教授的指导下种植了其单晶，并用阿姆斯特丹大学的De Visser博士测量了热膨胀。结果表明，alpha_a和alpha_b均通过开放的各向异性能量间隙急剧下降到7K以下。 Cenisn上的中子散射实验现在正在进行中。 Satoh博士已经成长为典型的超导材料Upd_2al_3的单一晶体，并系统地研究了物理特性。去年9月。我们举办了广岛的同伴系统的运输和热情特性研讨会，可以在我们的协作小组中深入讨论他们相互有趣的问题。最后，我们同意一项建议在我们的小组内密切联系的提案，即使在完成该项目后，也要就重力问题的问题进行密切联系。较少的

项目成果

T.TAKABATAKE: "Anisotropic Suppression of the Energy Gap in CeNiSn by High Magnetic Fields" Physical Review B. 45. 5740-5743 (1992)

T.TAKABATAKE：“高磁场对 CeNiSn 中能隙的各向异性抑制”物理评论 B. 45. 5740-5743 (1992)

V.Sechovsk'y: "Giont Magnetoresistance in UNiGa" J.Appl.Phys.70. 5794-5796 (1991)

V.Sechovsky：“UNiGa 中的巨磁阻”J.Appl.Phys.70。

T.Takabatake: "Structural,Magnetic,Transport and Thermal Properties of UCu_2Sn,UPt_2Sn and UAu_2Al" J.Phys.Soc.Jpn. 61. (1992)

T.Takabatake：“UCu_2Sn、UPt_2Sn 和 UAu_2Al 的结构、磁性、传输和热性能”J.Phys.Soc.Jpn。

T.Fujita: "Unusual Low Temperature Properties of Ce Compounds" J.Magn.Magn.Mat.(1992)

T.Fujita：“Ce 化合物的异常低温特性”J.Magn.Magn.Mat.(1992)

H.FUJII: "Anisotropic Hybridization in some Cerium and Цranium Compounds with Hexagonal ZrNiAl-type" Journal of Alloys and Compounds. 181. 111-121 (1992)

H.FUJII：“某些铈和钪化合物与六方 ZrNiAl 型的各向异性杂化”《合金与化合物杂志》181. 111-121 (1992)。