A study on magnetic excitation and phase separation in the vicinity of the quantum critical point(QCP) in the strongly correlated electron system(SCES)

强相关电子系统(SCES)量子临界点(QCP)附近的磁激发和相分离研究

• 批准号: 15340118
• 负责人: ISHIDA Kenji
• 金额: $ 10.82万
• 依托单位: Kyoto University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2004
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15340118/
• 关键词: Strongly Correlated Electrons Systems; Cuprate; Ruthenate; Cobaltate; Quantum Critical Point; non Fermi Liquid; Unconventional Superconductors; NMR μSR; 磁気励起; 銅酸化物高温超伝導体; ストライプ秩序

The aim of this program is to investigate the magnetic fluctuations around QCPs in cuprate, cobaltate, and ruthenate compounds, and heavy-fermion compounds including Ce,Yb and U ions using microscopic experimental techniques. Here, the QCP is the physical condition where the phase transition temperature is suppressed to the absolute zero by varying a physical parameter. Near the QCP, non-Fermi-liquid behavior is observed, which deviates from ordinary behaviors seen in normal metals. We use nuclear magnetic resonance (NMR) and muon spin resonance/rotation (μSR) as our microscopic experimental techniques. We have emphasized the use of μSR experiments when an NMR experiment is impossible due to the short relaxation time beyond the NMR experimental limit or in extremely low fields. We showed that the two experimental techniques are quite complementary to each other. In addition, we investigated the interplay between magnetism and unconventional superconductivity in the SCES from the microscopic point of view using NMR and μSR measurements.During the research period, we investigated the following subjects,a)magnetic fluctuations near the QCPb)the relation between magnetism and superconductivity in cuprate and HF compounds.c)Knight shift measurements in recently-discovered superconductorsd)Hydrate cobaltate superconductor.The results during the period are summarized, and are published as shown in the next page.

本计划的目的是调查周围的QCP在铜，钴，和铼化合物，和重费米子化合物，包括Ce，Yb和U离子使用微观实验技术的磁波动。这里，QCP是通过改变物理参数将相变温度抑制到绝对零度的物理条件。在QCP附近，观察到非费米液体行为，这与正常金属中看到的普通行为不同。我们使用核磁共振（NMR）和μ子自旋共振/转动（μSR）作为我们的微观实验技术。我们强调了当由于弛豫时间短而超出NMR实验极限或在极低的场中无法进行NMR实验时，μSR实验的使用。我们表明，这两种实验技术是相当互补的。此外，我们还利用NMR和μSR测量从微观角度研究了SCES中磁性和非常规超导性之间的相互作用。在研究期间，我们研究了以下课题：a）QCP附近的磁涨落b）铜酸盐和HF化合物中磁性与超导电性之间的关系c）最近发现的超导体中的奈特位移测量d）本文总结了这一时期的研究成果，并发表在下页。

项目成果

μSR and NMR in f-electron non-Fermi liquid materials

f电子非费米液体材料中的μSR和NMR

• 发表时间: 2003
• 期刊: Physica B-Condensed Matter 326
• 作者: D.E.MacLaughlin;M.S.Rose;B.L.Young;O.O.Bernal;R.H.Heffner;G.D.Morris;K.Ishida;G.J.Nieuwenhuys;J.E.Sonier
• 通讯作者: J.E.Sonier

K.Ishida, D.E.MacLaughlin, et al.: "μSR and Low-Temperature Antiferromagnetism in the Ordered Non-Fermi-Liquid Compound YbRh_2Si_2"Physica B. 329-333. 589-590 (2003)

K. Ishida、D. E. MacLaughlin 等人：“有序非费米液体化合物 YbRh_2Si_2 中的 μSR 和低温反铁磁性”Physica B. 329-333 (2003)。

K.Ishida, et al.: "Evolution of Normal-State Magnetic Fluctuations by Ca and Ti Substitutions in Sr_2RuO_4:^<87>Sr-NMR Study"Physical Review B. 67 214412. 1-6 (2003)

K.Ishida等：“Sr_2RuO_4中Ca和Ti取代的正常状态磁涨落的演化：^ 87>Sr-NMR研究”物理评论B.67 214412.1-6(2003)

Magnetic Fluctuations in the Metallic State of Na_<0.7>CoO_2 Revealed by ^<32>Na Nuclear Magnetic Resonance

^<32>Na核磁共振揭示Na_<0.7>CoO_2金属态磁涨落

• 发表时间: 2004
• 期刊: Journal of the Physical Society of Japan 73(11)
• 作者: Y.Ihara;K.Ishida;C.Michioka;M.Kato;K.Yoshimura;H.Sakurai;E.Takayama-Muromachi
• 通讯作者: E.Takayama-Muromachi

Spin dynamics in a structurally ordered non-Fermi-liquid compound : YbRh_2Si_2

结构有序的非费米液体化合物中的自旋动力学：YbRh_2Si_2

• 发表时间: 2003
• 期刊: Physica B 326
• 作者: K.Ishida;D.E.MacLaughlin;O.O.Bernal;R.H.Heffner;G.J.Nieuwenhuys;O.Trovarelli;C.Geibel;F.Steglich
• 通讯作者: F.Steglich