Quantum oscillation of the c-axis resistivity due to entrance of pancake vortices into micro-fabricated Bi₂Sr₂CaCu₂O_8+δ intrinsic Josephson junctions

The c-axis resistance in Bi₂Sr₂CaCu₂O_8+δ intrinsic Josephson junctions (IJJs) with areas of the ab-plane less than 2 μm² were measured as functions of applied magnetic field and angle to the crystalline axes. When the magnetic field is tilted off from the lock-in state of Josephson vortices, several sharp dips are found. The separation between the dips approaches to the value corresponding to φ₀ with further tilting the external magnetic field. This behavior is attributed to the penetration of a quantized pancake vortex into the tiny IJJ. This argument is further supported by the result that the c-axis resistance under magnetic fields parallel to the c-axis shows identical stepwise behavior