【摘要】 X射线衍射实验表明YBa₂(Cu_0.95M_0.05)₃O_7-δ（M=Ti,V,Cr,Mn,Fe,Co,Ni,Cu和Zn）均为单相结构。Fe,Co,Ni和Zn对Cu的替代使超导临界温度T_c显著下降,而同样含量的Ti,V,Cr,Mn对Cu的替代并未对超导性能产生显著影响。并利用中子衍射分析了Ti,Mn,Fe和Co对Cu原子的取代,发现代换原子对Cu的两个晶位各自存在不同的择优占据,从而为分析不同晶位Cu在超导机制中的作用提供了依据。同时,本文研究了YBa₂·(Cu_0.95M_0.05)₃O_7-δ的磁性,讨论了用3d金属离子代换Cu离子时对磁性的影响,以及磁性与超导性能之间的联系。更多还原

【Abstract】 YBa2(Cu_0.95M_0.05)₃O_7-δ were identified as single phase with M = Ti, V, Cr, Mn, Fe, Co, N₁, Cu and Zn. Substitution of Fe, Co, Ni and Zn for Cu makes T_o, decrease significantly, while at the same content, no distructuve effect on T_c was observed in the replacement of Cu with Ti, V, Cr and Mn. The site occupation of Ti, Mn, Fe and Co ions has been investigated by using neutron diffraction technique, and strong site preference for these ions were observed. Based on these results, the two diffrent Cu sites and their relationship to the superconductivity in YBa₂Cu₃sO_7-δ are discussed. The substitution effect for copper on magnetic properties in YBa2(Cu_0.95M_0.05)3O_7-δ and the correlation between magnetic and superconduc-tiviting properties are reported.更多还原