[[abstract]]In the resistive transition just below Tc, the c-axis dynamic resistance of a YBa2Cu3O7-δ single crystal as a function of the external dc magnetic field applied parallel to the ab-plane shows peaks suggestive of the existence of Josephson junctions within the single crystal. Two types of Josephson junctions can be inferred: one group formed by the CuO2-Y-CuO2 triple atomic planes within the same unit cell and the other by the bilayers of CuO2 planes from different unit cells. Secondly, the microwave-induced dc voltages across an unbiased single crystal exhibit behaviors that are consistent with the inverse ac Josephson effect, further indicating the existence of Josephson junctions within the single crystal.[[journaltype]]國內[[booktype]]紙本[[countrycodes]]TW
