Current-Induced Superconductor-Insulator Transition in Granular High-T_c Superconductors

In this work we report a systematic study of electrical current effects on superconducting properties of granular Y$_{1-x}$Pr$_{x}$Ba$_{2}$Cu$_{3}$O$_{7-\delta}$ samples with x close to the critical Pr concentration above which the superconductivity vanishes. The results indicate the occurrence of superconductor-insulator quantum phase transition (SIT) driven by the applied electrical current, and suggest that the current-induced SIT can be considered as the dynamical counterpart of the magnetic-field- tuned SIT.