High field magnetism of the high-T_c superconducting materials and related materials.

高T_c超导材料及相关材料的高场磁性。

• 批准号: 02640257
• 负责人: SUGIYAMA Kiyohiro
• 金额: $ 1.15万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1990
• 资助国家: 日本
• 起止时间: 1990 至 1991
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02640257/
• 关键词: High-T_c Superconductor; High Magnetic field; Two Dimensional Conductivity; Rare Earth compounds; Magnetization Measurement; Magnetoresistance; Multi-step Magnetization; Staggered Field

The high-field magnetizations of R_2CuO_4 related compounds of high-T_c superconductors were investigated systematically in this year. The angular dependence of magnetization and the low temperature measurement of[110]direction are observed in Nd_2CuO_4. It is discovered that the two peaks of dM/dH at 1.3 K observed previously separate into three peaks below 1 K. This change may be related with the transition around 1 K given by the neutron diffraction study but detail is not known up to now. Next, the magnetization of Ce doped materials which show the superconductivity after the reduction treatment. The transition field and saturation field of Nd moment decrease as concentration of Ce increase but do not become zero at the concentration which is the onset of the superconductivity.The consideration of the multistep magnetization of Gd_2CuO_4 was done and it is inferred that the canting due to the Dzyaloshinski Moriya interaction of Cu-spins which is connected to Gd-spin by staggered field play important role on this anomalous magnetization. However, The frustration on the Gd spin system is important and further consideration is necessary.There is a problem that the ln T dependence on the electrical resistivity which is observed on Nd_<2-x>Ce_x, CuO_4 is the general character on all high-T_c superconductors. This effect is observed when the residual resistivity is enough large. Therefore, the test of the sample preparation with large residual resistivity is done with Dr. Hidaka(NTT). The experiment is possible to carry out and we applied the next year research project of Grant-in-Aid for Scientific Research.

本文系统地研究了高温超导体R_2CuO_4相关化合物的强场磁化。在Nd_2CuO_4中观察到了[110]方向的磁化强度随角度的变化和低温测量。发现以前观察到的dM/dH在1.3K时的两个峰在1 K以下分离成三个峰。这种变化可能与中子衍射研究给出的1 K附近的跃迁有关，但具体细节目前尚不清楚。其次，研究了还原处理后具有超导电性的Ce掺杂材料的磁化强度。Nd磁矩的过渡场和饱和场随Ce浓度的增加而减小，但在超导起始浓度处并不为零，对Gd_2CuO_4的多阶磁化进行了考虑，推测这种反常磁化是由于Cu自旋与Gd自旋之间的Dzyaloshinski Moriya相互作用引起的倾斜所致。然而，Gd自旋系统的挫折是重要的，有必要进一步考虑。有一个问题是，在Nd_ Ce_x，CuO_4上观察到的lnT对电阻率的依赖<2-x>性是所有高T_c超导体的共同特征。当剩余电阻率足够大时，观察到这种效应。因此，日高博士（NTT）进行了剩余电阻率大的样品制备试验。本实验是可行的，并申请了下一年度的科研资助项目。

项目成果

Y. Hidaka, Y. Tajima, K. Sugiyama, F. Tomiyama, A. Yamagishi, M. Date and M. Hikita: "Two-dimensional weak localization in electron high-T_c superconductor Nd_<2-x>Ce_xCuO_y under high magnetic field." Phys. Soc. Jpn.60, no. 4. 1185-8 (1991)

Y. Hidaka、Y. Tajima、K. Sugiyama、F. Tomiyama、A. Yamagishi、M. Date 和 M. Hikita：“强磁下电子高 T_c 超导体 Nd_<2-x>Ce_xCuO_y 的二维弱局域化

K.Sugiyama: "Magnetization of R_2CuO_4 (R=Nd,Pr,Gd) single Crystals" Journal of Magnetism and Magnetic Materials.

K.Sugiyama：“R_2CuO_4 (R=Nd,Pr,Gd) 单晶的磁化”《磁性与磁性材料杂志》。

K.Sugiyama: "Kondoーlike effect in electron highーT_c superconductor Nd_<2-x>Ce_xCuO_y" Journal of Magnetism and Magnetic Materials. 90&91. 687-688 (1990)

K.Sugiyama：“电子高温超导体 Nd_<2-x>Ce_xCuO_y 中的近藤效应”《磁性与磁性材料杂志》90&91 (1990)。

Y.Hidaka: "Two-dimensional Weak Localization in High-T_C Superconductor Nd_<2-x>Ce_XCuO_y under High Magnetic Field" Journals of physical Society of Japan. 60. 1185-1188 (1991)

Y.Hidaka：“高磁场下高温超导Nd_<2-x>Ce_XCuO_y的二维弱局域化”日本物理学会期刊。

Kiyohiro Sugiyama: "Anomalous StepーMagnetization in Gd_2CuO_4 Single Crystal" Journal of Physical Society of Japan.

Kiyohiro Sugiyama：“Anomalous Step－Magnetization in Gd_2CuO_4 Single Crystal”日本物理学会杂志。