Research of New type of Superconductors in Tetragonal HoCoGa5-type Crystal Structure

四方HoCoGa5型晶体结构新型超导体研究

• 批准号: 16540317
• 负责人: INADA Yoshihiko
• 金额: $ 2.18万
• 依托单位: Okayama University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16540317/
• 关键词: samarium compound; heavy fermion superconductor; single crystal growing; strongly correlated electron systems; magnetism; SmTIn5; HoCoGa_5; SmTIn_5; 単結晶育成; フラックス法; 超伝導

The tetragonal HoCoGa_5-type crystal structure is known as a tetragonal variant of the AuCu_3-strucuture in which new superconductors were discovered. CeMIn_5 (M : Co, Rh, Ir) compounds exhibit a variety of interesting properties such as non-s-superconductivity, a first-order transition near the upper critical field, heavy-fermion behavior, pressure-induced superconductivity, etc. In the exotic heavy fermion superconductors, Cooper pairs are expected formed by the exchange of magnetic spin fluctuations, in which f-electrons which are not simply localized play an important role. A large specific heat coefficient and Curie-Weiss behavior in the normal state or low anti-ferromagnetic ordering temperatures are features of the exotic heavy fermion superconductors. PuCoGa_5 and PuRhGa_5 are known as heavy fermion "high T_c" superconductors. Pu has valence states of Pu^<3+>(5f^5), PU^<4+>(5f^4), PU^<5+>, Pu^<6+> in Pu-based compounds, while Sm has Sm^<2+>(4f^6), Sm^<3+>(4f^5). Sm^<3+>(4f^5) and Pu^<3+>(5f^5) ions have the same J=5/2 multiplet, and show the local moment behavior, i.e., obey a Curie-Weiss law. It is interesting that it depends on the particular crystal structure whether Sm compounds show exotic behavior or not.We have succeeded in growing single crystals of. SmMIn_5 (M : Co, Rh, Ir) by the flux method. There was no report of the physical properties on single crystalline SmCoIn_5. Specific heat measurement, magnetization measurements and electrical resistivity measurements were performed on SmMIn_5.SmRhIn_5 and SmIrIn5 showed the antiferromagnetic ordering and extra transitions below T_N, which is almost same as the results in the previous report. SmCoIn_5 also showed the antiferromagnetic ordering and extra transitions below T_N 11.9 K. The temperatures of these anomalies are 6, 7.6 and 11.9 K and lowest found in SmMIn_5 compounds.

四方HoCoGa5型晶体结构是AuCu3-结构的一个四方变体，在这种结构中发现了新的超导体。CeMin_5(M：Co，Rh，Ir)化合物表现出许多有趣的性质，如非S超导电性、在上临界场附近的一级相变、重费米子行为、压力诱导超导电性等。在奇异的重费米子超导体中，库珀对是通过磁自旋涨落交换而形成的，其中f电子在其中起着重要的作用。高比热系数和正常状态下或低反铁磁有序温度下的居里-魏斯行为是奇异重费米子超导体的特点。PuCoGa5和PuRhGa5被称为重费米子“高T_c”超导体。在Pu基化合物中，Pu的价态为Pu^&lt；3+&gt；(5f^5)，Pu^&lt；4+&gt；(5f^4)，Pu^&lt；5+&gt；，Pu^&lt；6+&gt；而Sm有Sm^&lt；2+&gt；(4f^6)，Sm^&lt；3+&gt；(4f^5)。Sm^&lt；3+&gt；(4f^5)和Pu^&lt；3+&gt；(5f^5)离子具有相同的J=5/2多重态，并表现出局域矩行为，即服从居里-魏斯定律。有趣的是，Sm化合物是否表现出奇异的行为取决于特定的晶体结构。我们已经成功地生长了单晶。用助熔剂法制备了SmMIn_5(M：Co，Rh，Ir)。SmCoIn_5单晶的物理性质尚未见报道。对SmCoIn_5进行了比热测量、磁化强度测量和电阻率测量，发现SmRhIn_5和SmIrIn5在T_N以下有反铁磁有序和额外的相变，这与以前的报道基本一致。在TN 11.9K以下，SmCoIn_5也表现出反铁磁有序和额外的相变，这些反常温度分别为6，7.6和11.9K，在SmMIn_5化合物中最低。

项目成果

Probing the extended non-Fermi liquid regimes of MnSi and Fe

探索 MnSi 和 Fe 的扩展非费米液态

• 发表时间: 2006
• 期刊: Physica B 165
• 作者: Y.Watanabe;Y.Inada et al.;P.Pedrazzini et al.
• 通讯作者: P.Pedrazzini et al.

XMCD study on ferromagnetic superconductor UGe2

XMCD铁磁超导体UGe2研究

• 发表时间: 2005
• 期刊: Physica B 359
• 作者: Y.Watanabe;Y.Inada et al.;P.Pedrazzini et al.;T.Okane et al.;Y.Inada et al.;Y.Inada et al.
• 通讯作者: Y.Inada et al.

Unconventional superconductivity and non-Fermi liquid behaviour of epsilon-iron at high pressure

高压ε铁的非常规超导性和非费米液体行为

• 发表时间: 2004
• 期刊: Journal of Physics Condensed Matter 16
• 作者: M.Nishiyama;Y.Inada;G.Q.Zheng;H.Shishido et al.;T.Ueda et al.;H.Shishido et al.;T.Ueda et al.;Y.Iida et al.;A.T.Holmes et al.
• 通讯作者: A.T.Holmes et al.

Soft X-ray Absorption Magnetic Circular Dichroism Study of Ferromagnetic Superconductor UGe_2

铁磁超导体UGe_2的软X射线吸收磁圆二色性研究

• 发表时间: 2006
• 期刊: J. Phys. Soc. Jpn. 75
• 作者: Y. Uratani;T. Shishidou;F. Ishii and T. Oguchi;H. Uzu and A. Tanaka;J.I.Hwang;Hua Wu;M.W.Haverkort;Hisashi Uzu;A.Tanaka;H.Sato;H.Uzu;T.Okane
• 通讯作者: T.Okane

Superconductivity of the ternary boride Li_2Pd_3B probed by B^11 NMR

B^11 NMR探测三元硼化物Li_2Pd_3B的超导性

• 发表时间: 2005
• 期刊: Physical Review B 71
• 作者: Y.Watanabe;Y.Inada et al.;P.Pedrazzini et al.;T.Okane et al.;Y.Inada et al.;Y.Inada et al.;M.Nishiyama
• 通讯作者: M.Nishiyama