摘要： Superconducting transition temperature T_c and normal-state electrical resistivities ρ of the Tm_1-xPr_xBa₂Cu₃O_7-δ system have been measured. The results indicate that T_c remains constant for x = 0 to 0.08 before it drops steadily with higher x. Following the Abrikosov-Gor'kov model, a total suppression of superconductivity occurs at a critical Pr concentration x_cr≈0.56. It is found for the first time, as far as we know, that the logarithmic resistivity at 270 K increases linearly with increasing x, yielding ρ= ρ₀e^ax. Judging from the relation between dρ/dT and x, a metal to insulator transition occurs just beyond x_cr.

Abstract: Superconducting transition temperature T_c and normal-state electrical resistivities $\rho$ of the Tm_1-xPr_xBa₂Cu₃O_7-$\delta$ system have been measured. The results indicate that T_c remains constant for x = 0 to 0.08 before it drops steadily with higher x. Following the Abrikosov-Gor'kov model, a total suppression of superconductivity occurs at a critical Pr concentration x_cr≈0.56. It is found for the first time, as far as we know, that the logarithmic resistivity at 270 K increases linearly with increasing x, yielding $\rho$ = $\rho$₀e^ax. Judging from the relation between d$\rho$/dT and x, a metal to insulator transition occurs just beyond x_cr.

中图分类号: 

• 74.25.Fy

74.62.-c (Transition temperature variations, phase diagrams)