Local Non-Fermi-Liquid Anomaly and Inter-Site Effects of 5f Electron Systems

5f电子系统的局部非费米液体异常和位点间效应

• 批准号: 10440096
• 负责人: AMITSUKA Hiroshi
• 金额: $ 3.52万
• 依托单位: HOKKAIDO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10440096/
• 关键词: Non Fermi Liquid; Kondo Effects; Multi-Channel Kondo Effects; Non-Kramers Configuration; Heavy Fermion; Weak Antiferromagnetism; Pressure Effects; Neutron Scattering; ウラン希薄合金; 非クラマース電子系; 比熱; 電気抵抗

Single-U-ion properties of heavy-electron compound URuィイD22ィエD2SiィイD22ィエD2 have been investigated by a series of diluting experiments on RィイD21-xィエD2UィイD2xィエD2RuィイD22ィエD2SiィイD22ィエD2(R=Y, Th; x 【less than or equal】0.07). A strong uniaxial magnetic anisotropy of local 5f moments is commonly observed throughout the dilutions. From a large enhancement of Χ and C/T at T → 0, we suggest a non-Kramers, magnetic doublet ΓィイD25ィエD2 (fィイD12ィエD1) to be eminently suitable for the crystal-field lowest level, contrary to general views of low-lying singlets for the periodic system. We have further confirmed absence of the conventional Kondo effect in all these dilutions. A strong suppression of 5f moments at low temperatures accompanies a non-trivial lnT decrease in ρ and a small change in the magnetic entropy. Specific-heat measurements in magnetic fields up to 12 T have revealed no sign of the residual entropy, eliminating the simple application of the two-channel Kondo theory to the present alloys. We have also found through neutron-scattering experiments that the periodic system URuィイD22ィエD2SiィイD22ィエD2 undergoes a new phase transition under high pressure.

通过对重电子化合物R_（21-x）Ru_（21-x）D_2U_（21-x）D_2Ru_（22-x）D_2Si_（22-x）D_2Si_（22-x）D_2（R=Y，Th; x ≤ 0.07）的一系列稀释实验，研究了重电子化合物URu_（22-x）D_2Si_（22-x）D_2Si_（22-x）D_2的单U离子性质。一个强大的单轴磁各向异性的本地5 f时刻通常观察到整个稀释。从T → 0时的ε和C/T的大幅度增强，我们认为非Kramers的磁性二重态Γ D25 <$D2（f <$D12 <$D1）非常适合于晶体场的最低能级，这与周期系统的低单态的一般观点相反。我们进一步证实，在所有这些稀释中都不存在传统的近藤效应。在低温下，5 f矩的强烈抑制伴随着ρ的非平凡lnT降低和磁熵的微小变化。在高达12 T的磁场中的比热测量没有发现剩余熵的迹象，消除了双通道近藤理论对本合金的简单应用。我们还通过中子散射实验发现，周期系统URu <$D22 <$D2Si <$D22 <$D2在高压下经历了一个新的相变。

项目成果

H.Amitsuka: "Effect of Pressure on Ting Antiferromagnetic Moment in the Heavy-Electron Compound URu_2Si_2"Phys.Rev.Lett.. 83. 5114-5117 (1999)

H.Amitsuka：“压力对重电子化合物 URu_2Si_2 中 Ting 反铁磁矩的影响”Phys.Rev.Lett.. 83. 5114-5117 (1999)

H.Amitsuka: "Pressure-Inoluced Magnetic Phase Transition of the 5f Electronic System URu_2Si_2"J.Phys.Soc.Jpn.. (印刷中). (2000)

H.Amitsuka：“5f 电子系统 URu_2Si_2 的受压磁相变”J.Phys.Soc.Jpn..（出版中）。

H. Amitsuka: "Effect of Pressure on Tiny Antiferromagnetic Moment in the Heavy-Electron Compound UruィイD22ィエD2SiィイD22ィエD2"Phys. Rev. Lett.. 83. 5114-5117 (1999)

H. Amitsuka：“压力对重电子化合物中微小反铁磁矩的影响 Phys. Rev. Lett.. 83. 5114-5117 (1999)

H.Sato: "Hall Effect and Thermoelectric Power in the Systems Exhibiting the Non-Fermi Liquid Behaviors"Physica B. 259-261. 390-391 (1999)

H.Sato：“展示非费米液体行为的系统中的霍尔效应和热电功率”Physica B.259-261。

N.Metoki: "Neutron-Scattering Studies on Heavy-Fermion Superconductors"Physica B. (印刷中). (2000)

N.Metoki：“重费米子超导体的中子散射研究”Physica B.（出版中）。