Tunneling in Pb-YBCO junctions: Determining the symmetry of the pairing state

Abstract

We report on our efforts to understand the origin of supercurrent observed in c-axis tunnel junctions on YBCO [Sun A. G. et al., Phys. Rev. Lett. 72, 2267 (1994).] by studying the phase coherence of a-axis/c-axis and b-axis/c-axis Pb-YBCO SQUIDs and Josephson junctions. We also discuss the quasiparticle tunneling spectra measured in c-axis Pb-YBCO junctions which should give information about the pairing mechanism responsible for high temperature superconductivity. © 1995.