NONEQUILIBRIUM CHARACTERISTICS OF INTRINSIC Bi_2.3Pb_0.1Sr₂CaCu₂O_8+y JOSEPHSON JUNCTIONS

Using photolithography and Ar ion milling, we fabricate small mesas on top of the Bi_2.3Pb_0.1Sr₂CaCu₂O_8+y single crystals to study the inherent tunnelling property of intrinsic Josephson junctions. The I-V characteristics of the mesas show a typical multiple branches with large hysteresis. The return current I_r depends on the N-th branch. The relation of I_r and N follows I_r=I₀*N^m, where -1<m<0 might be related to the Coulomb blockade effect. The McCumber parameter β_c of the samples is also investigated.