C-axis current-voltage characteristics of mesa structures on Bi2Sr2CaCu2O8+delta single crystals fabricated by a simple technique without photolithography

A simple technique-is reported for fabricating the mesa structure on Bi2Sr2 CaCu2O8+delta single crystal. In the patterning process, metal masks are us ed instead of photolithography and argon ion milling is applied to form the small mesa on the Bi2Sr2CaCu2O8+delta crystal surface, Real four-probe tra nsport measurements are made on the mesa structure and typical c-axis curre nt-voltage (I-V) characteristics of the intrinsic Josephson effect have bee n observed. The superconducting gap parameter can be extracted from the mul ti-branch structure in the I-V characteristics. Additionally, from the stro ng hysteresis in the I-V characteristics, the capacitance C-J of the unit i ntrinsic Josephson junction has been estimated to be 2.3pF, which is in goo d agreement with that evaluated from the geometric parameters of the unit f unction between the two copper oxide layers.