NMR Study on the Strong Electron Correlations in Superconducting Cu Spinel Sulfides

超导铜尖晶石硫化物中强电子相关性的核磁共振研究

• 批准号: 08454097
• 负责人: WADA Shinji
• 金额: $ 1.47万
• 依托单位: KOBE UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08454097/
• 关键词: Cu Spinel sulfides; itinerant weakly antiferromagnetism; superconductivity; electron correlations; Structural phase transition; 超伝導と磁性; 核磁気共鳴; 強相関電子物性; 遍歴型反強磁性; スピネル硫化物

1. Coexistence of the superconductivity with itinerant weakly antiferromagnetism in CuCo2SィイD24ィエD2A coherence peak and an exponential temperature dependence of the spin-lattice relaxation rate observed in the superconducting state indicate that the system belongs to a group of a s-wave superconductors. It is confirmed microscopically that the itinerant weakly-antiferromagnetism coexists with the superconductivity.2. Itinerant weakly antiferromagnetism in (Cu, Co) CoィイD22ィエD2SィイD24ィエD2 systemWe found that the itinerant weakly antiferromagnetism originating from the A-sites appears in both the Cu-rich and the Co-rich regions, while the superconductivity appears in the limit of the Cu-rich region.3. Structural phase transition and temperature-induced magnetism in CuVィイD22ィエD2SィイD24ィエD2The anomalies that have been observed below 90 K in many physical quantities are well explained by the change in the electronic state of V3+ associated with a structural transition at 90 K from the high-temperature cubic phase to a low-temperature tetragonal phase.4. Itinerant weakly magnetism in CuTiィイD22ィエD2SィイD24ィエD2The low temperature susceptibility, specific heat, and NMR measurements indicate that CuTiィイD22ィエD2SィイD24ィエD2 is not a simple Pauli paramagnet but belongs to a group of itinerant weakly antiferromagnets, and exhibits somewhat long-range order below 5K.

1. CuCo2D24D2A相干峰中超导性与流动弱反铁磁性的共存以及超导状态下观察到的自旋晶格弛豫率的指数温度依赖性表明该系统属于一组s波超导体，这在微观上得到了证实。巡回弱反铁磁性与弱反铁磁性共存2. (Cu, Co)体系中的流动弱反铁磁性我们发现富Cu和富Co区域均出现了源自A位的流动弱反铁磁性，而超导性则出现在Cu的极限区域。 -富集区。3。在90 K 以下观察到的许多物理量的异常现象可以通过与90 K 时从高温立方相到低温四方相的结构转变相关的V3+ 电子态的变化得到很好的解释。4． CuTiD22D2S中流动弱磁低温磁化率、比热和核磁共振测量表明，CuTiD22D2S不是简单的泡利顺磁体，而是属于一组流动弱反铁磁体，并且在5K以下表现出一定的长程有序。

项目成果

Shinji Wada: "Structural phase transition and low energy spin excitations in CuVィイD22ィエD2SィイD24ィエD2spinel"Journal of Magnetism and Magnetic Materials. Vol.177-181. 1393-1394 (1988)

Shinji Wada：“CuViD22D2SD24D24D2尖晶石中的结构相变和低能自旋激发”《磁性与磁性材料杂志》第 177-181 卷（1988 年）。

Toshio Fukai: "NMR Study of Antiferromagnetic Spinel CoCoィイD22ィエD2OィイD24ィエD2 in Paramagnetic and Ordered State"Journal of Physical Society of Japan. Vol.65. 4067-4071 (1996)

Toshio Fukai：“顺磁性和有序状态下的反铁磁性尖晶石 CoCoD22D2OD24D2 的核磁共振研究”日本物理学会杂志第 65 卷 4067-4071（1996 年）。

Y.Yoshikawa et al.: "NMR investigation of a structural phase transition and temperature induced magnetism in copper thiospinel CuV_2S_4" Physical Review B. 55,1. 74-77 (1997)

Y.Yoshikawa 等人：“铜硫尖晶石 CuV_2S_4 结构相变和温度诱导磁性的 NMR 研究”物理评论 B. 55,1。

S.Wada et al.: "Structural phase transition and low energy spin excitations in CuV_2S_4 spinel" Journal of Magnetism and Magnetic Materials. (in print). (1998)

S.Wada 等人：“CuV_2S_4 尖晶石中的结构相变和低能自旋激发”《磁性与磁性材料杂志》。

吉川裕次、和田信二,他4名: "Nuclear spin-latticarelation aulaitiffevro magnetic spin cornelations in super conducting thicspirol Cu_Co_S_4" Physicul Raview B. 51.9. 6159-6162 (1995)

Yuji Yoshikawa、Shinji Wada 和其他 4 人：“超导 thicspiroll Cu_<1.5>Co_<1.5>S_4 中的核自旋晶格关联磁自旋关联”Physicul Raview B. 6159-6162 (1995)。