Rare-earth substitution in High temperature superconductor R123

摘要

We have studied the structural and electrical properties of single phase Gd(Ba_(2-x)La_x)Cu_3O_(4+delta) [Gd(BaLa)123], Gd(Ba_(2-x)Nd_x)Cu_3O_(7+delta) [Gd(BaNd)l23] and Nd(Ba_(2-x)Pr_x)Cu_3O_(7+delta) [Nd(BaPr)l23] (00.5 several impurity peaks turn up in the range of 29°<0<31° which indicates the amount of doping is more than solubility limit. The estimated solubility limit for La doping is 1.14 while it is about 0.55 in Gd(BaNd)123 and 0.6 in Nd(BaPr)123. The resistivity measurements show that the increase of Nd doping is more effective than La in increasing resistivity and decreasing T_c in Gd123. The comparison of these results with them in Gd(BaPr)123 shows that the effect of Pr at Ba site in Gd123 is similar to the effect of Nd at Ba site in suppression superconductivity. Also Pr at Ba site in Nd123 is mere effective than in Gd123 in suppression superconductivity.