Tunneling investigation of the gap-like feature in superconducting Y1-xPrxBa2Cu3O7 thin films

摘要

We have measured the conductance of Y$-1-x$/Pr$-x$/Ba$-2$/Cu$-3$/O$-7$//Pb planar tunnel junctions fabricated on thin films where x equals 0, 0.2 and 0.4. When tunneling into the ab-plane, there is a weak decrease in conductance at eV approximately 2k$-B$/T$-c$/, where a superconducting gap is expected. With increasing Pr concentration, the energy where this gap-like feature appears is reduced by an amount commensurate with the reduction in T$- c$/. The gap-like structure in the c-axis tunneling conductance becomes weaker, but displays no change in energy when YBCO is doped with Pr.