Neutron Scattering Study of the One-dimensional Magnetic Anisotropy on the CuO_2 Plane of the Domain-controlled High T_c Superconductors

域控高温超导体CuO_2面一维磁各向异性的中子散射研究

• 批准号: 15340109
• 负责人: HIROTA Kazuma
• 金额: $ 9.54万
• 依托单位: The University of Tokyo
• 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 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-15340109/
• 关键词: high T_c superconductivity; La_<2-x>Sr_xCuO_4; Neutron scattering; One-dimensional spin modulation; Spin dynamics; Bi high T_c superconductors; Impurity effect; Bi_2Sr_<2-x>La_xCuO_6; Bi_2Sr_2CaCu_2O_8; Dewtinning; La_<2-x>Sr_XCuO_4

Since it is difficult to grow large single crystals for highly anisotropic or domain-controlled high T_c superconductors, it is necessary to increase the effective volume by aligning multiple crystals to carry out neutron scattering. We thus have established a method to align many single crystals precisely and efficiently : Combination of a high-energy x-ray diffractometer and a CCD camera, as well as a supersensitive CCD camera with neutron scintillator have been developed. We have succeeded in obtaining the effective volume of 0.53cc by aligning six Bi2212 single crystals with a very high precision, which is about eight times as large as a typical sample volume in previous studies. We have been carrying out series of neutron scattering experiments at the Oak Ridge National Laboratory through the US-Japan cooperative program on neutron scattering to search for the magnetic excitation and the resonance peak.To elucidate the relation between superconductivity and antiferromagnetic spin dynamics, we have performed a systematic inelastic neutron scattering concerning the suppression of T_c by impurities and the change of the spin excitations, using optimally doped La_<2-x>Sr_xCuO_4 single crystals with very small amount of impurities. We have focused upon the non-magnetic impurity Zn and the magnetic impurity Ni : Since the former suppresses T_c more effectively the latter, we expected to clarify how the magnetism is related to the T_c suppression mechanism by comparing both the systems. As to the Zn doped system, a novel in-gap state appears in the middle of the previously know spin gap while the overall spin dynamics does not change much. On the other hand, the spin dynamics of the Ni doped systems is renormalized to the lower energies as T_c is suppressed. It is now clear that the Zn and Ni doping effects on the superconductivity on the CuO_2 plane is qualitatively different.

由于高各向异性或域控高T_c超导体难以生长出大的单晶，因此有必要通过排列多晶来增加有效体积来进行中子散射。因此，我们建立了一种精确而有效地对准许多单晶的方法：研制了高能x射线衍射仪与CCD相机的组合，以及超灵敏CCD相机与中子闪烁体的组合。我们通过对6个Bi2212单晶进行非常高精度的对准，成功获得了0.53cc的有效体积，这大约是以往研究中典型样品体积的8倍。我们通过美日中子散射合作项目，在橡树岭国家实验室进行了一系列中子散射实验，寻找磁激发和共振峰。为了阐明超导性和反铁磁自旋动力学之间的关系，我们利用掺杂极少量杂质的La_<2-x>Sr_xCuO_4单晶，对杂质对T_c的抑制和自旋激发的变化进行了系统的非弹性中子散射。我们将重点放在非磁性杂质Zn和磁性杂质Ni上：由于前者比后者更有效地抑制T_c，我们希望通过比较这两种体系来阐明磁性与T_c抑制机制的关系。对于掺杂Zn的体系，在已知的自旋间隙中间出现了一个新的隙内态，而整体的自旋动力学变化不大。另一方面，当T_c被抑制时，Ni掺杂体系的自旋动力学被重新规范化到较低的能量。结果表明，Zn和Ni掺杂对CuO_2平面上超导性的影响在性质上是不同的。

项目成果

Stoner gap in the superconducting ferromagnet UGe_2

超导铁磁体 UGe_2 中的斯托纳间隙

• 发表时间: 2006
• 期刊: Phys. Rev. B 73
• 作者: Ryouji Matsuda;Akinobu Kanda;Youiti Ootuka;R.A.Ribeiro;N.Aso et al.
• 通讯作者: N.Aso et al.

^<17>O NMR study of the inhomogeneous electronic state in La_<2-x>Sr_xCuO_4 crystals^1

^<17>O NMR研究La_<2-x>Sr_xCuO_4晶体中非均匀电子态^1

• 发表时间: 2005
• 期刊: Physical Review B 72
• 作者: P.M.Singer;T.Imai;F.C.Chou;K.Hirota;M.Takaba;T.Kakeshita;H.Eisaki;S.Uchida
• 通讯作者: S.Uchida

Neutron diffraction study on the antiferromagnetic insulating ground state of b-Na_<033>V_2O_5

b-Na_<033>V_2O_5反铁磁绝缘基态的中子衍射研究

• 发表时间: 2005
• 期刊: Journal of the Physical Society of Japan 74
• 作者: S.Nagai;M.Nishi;K.Kakurai;Y.Oohara;H.Yoshizawa;H.Kimura;Y.Noda;B.Greiner;T.Yamauchi;J.Yamamura;M.Isobe;Y.Ueda;K.Hirota
• 通讯作者: K.Hirota

Hole concentration dependence of Mn e(g) orbital state in bilayer manganites studied by magnetic Compton profile measurement

通过磁康普顿剖面测量研究双层锰氧化物中 Mn e(g) 轨道状态的空穴浓度依赖性

• 发表时间: 2005
• 期刊: PHYSICAL REVIEW B 66(12)
• 作者: Koizumi;A;Nagao;T;Kakutani;Y;Hiraoka;N;Sakai;N;Arima;T;Hirota;K;Murakami;Y
• 通讯作者: Y

Electronic excitations in hole-doped La_<1-x>Sr_xMnO_3 studied by resonant inelastic X-ray scattering.

通过共振非弹性X射线散射研究了空穴掺杂La_<1-x>Sr_xMnO_3中的电子激发。

• 发表时间: 2005
• 期刊: J. Phys. Chem. Solids 66
• 作者: K.Ishii;T.Inami;K.Ohwada;K.Kuzushita;J.Mizuki;Y.Murakami;S.Ishihara;Y.Endoh;S.Maekawa;K.Hirota;Y.Moritomo
• 通讯作者: Y.Moritomo