作　　者： ; ; ; ; ; ; ;

机构地区： 中国科学技术大学物理学院物理系

出　　处： 《低温物理学报》 1990年第1期51-57,共7页

摘　　要： 采用固相反应法制备了单相元素替代超导氧化物系列 GdBa_2Cu_(3-x)Co_xO_y,NdBa_2Cu_(3-x)Co_xO_y对这些样品的晶格常数和电阻-温度关系进行了测量,发现随掺杂量 x 的增加,①两系列样品均呈现出金属-半导体转变;②NdBa_2Cu_(3-x)Co_xO_y 出现一从正交到四方的结构相变,并且在发生该相变之前,超导电性已消失;③GdBa_2Cu_(3-x)Co_xO_y 的 T_c(x)随 x 变化近似成线性关系.取适当的 x_(cr),与 AG 曲线比较,发现在高含量区出现偏差.将本实验结果与 YBa_2Cu_(3-x)Co_xO_(7-δ)、YBa_2Cu_(3-x)Fe_xO_(7-δ),YBa_2Cu_(3-x)Ni_xO_(7-δ),GdBa_2Cu_(3-x)Fe_xO_(7-δ)等系列相应的结果作比较,认为磁性稀土元素与固有磁矩较大的过渡元素间很可能存在某种磁相互作用.同时还讨论了其它可能的拆对机制. The single phase substituted superconducting oxide series of GdBa2Cu3-xCoxOy,NdBa2 Cu3-xCoxOy have been prepared by solid state reaction,and,the lattice parameters and the dependence of resistance on temperature have been measured.It is found that,with the increase of the substituting amount x,(1) both the two series of samples show metal-semiconductor transition; (2) NdBa2Cu3-xCoxOy apperas a structural transition from an orthorhombic to a tetragonal one and the superconductivity vanishes before this transition; and (3) the Tc of GdBa2Cu3-xCoxOy decreases linearly with x.By selecting appropriate xcr and comparing with AG curve,the deviation from AG theory in the high impurity content region is found.Comparing with YBa2Cu3-xCoxO7-y Ba2Cu3-xFexC7-y YBa2Cu3-xNixO7-y GdBa Cu3-yFexO7-y we suggest that there may exist some magnetic interaction between rare-earth elements and 3d-metals with large intrinsic magnetic monent.Simultaneously,other possibles depairing mechanism is discussed,too.

关 键 词： 氧化物 超导体 超导电性

领　　域： [电气工程] [一般工业技术]