We report the measurements on the ramp-edge type Josephson and quasiparticle tunnel junctions with the different interface angle geometry using high-Tc YBa2Cu3O7-y (YBCO) electrodes. The YBCO/I/Ag tunnel junctions with different crystal-interface boundary angles are fabricated for the investigation of zero bias conductance peak. The angle dependent zero bias conductance peak typical to a dx2-y2-wave superconductor is observable. For Josephson junctions, YBCO ramp-edge junctions with different ab-plane electrodes relatively rotated by 45are fabricated using a CeO2 seed-layer technique. The temperature dependence of the maximum Josephson current for YBCO/PBCO/YBCO junctions (PBCO: PrBa2Cu3O7-y) exhibits angle-dependent behavior, qualitatively different from the Ambegaokar-Baratoff prediction. Under microwave irradiation of 9 GHz, the Shapiro steps appear at integer and/or half integer multiples of the voltage satisfying Josephson voltage-frequency relation, whose behavior depends on the sample angle geometry. The results are reasonably interpreted by the dx2-y2-wave theory by taking the zero energy state into account.

A measurement system is developed to observe the switching current distribution in Bi2Sr2CaCu2O8+δ intrinsic Josephson junctions (IJJ's). We have designed the frequency responses of filters and cables to achieve the compatibility of sufficient isolation at high frequency region and accurate detection of the distribution at low frequency region. The temperature dependence of the switching current distributions measured on a IJJ by the present system agrees well with the theoretical calculation in the temperature range from 70 mK to 5 K. The consistency of the crossover temperature between experimental result and calculation suggests that the designed measurement system succeeded in observing the macroscopic quantum tunneling process.