Short pulse tunneling measurements of the intrinsic Josephson junctions in Bi-Sr-Ca-Cu-O

We have measured the I-V characteristics of intrinsic Josephson junction stacks fabricated on the surface of a Bi/sub 2/Sr/sub 2/CaCu/sub 2/O/sub 8+/spl delta// crystal. In order to reduce the Joule heating, which necessarily occurs associated with these measurements, we have reduced the number of junctions in the stack to approximately 10, and then adopted the short pulse measurement method. With these measures, it becomes possible to observe I-V characteristics which have a clear gap structure with slight gap suppression due to current injection. The voltage response analysis indicates that the magnitude of the gap suppression is no greater than 3% at the maximum. The estimated gap parameter is 50 mV for a single junction.