Tunneling characteristics for Bi2212 intrinsic Josephson junctions with little influence of self-heating using short pulse technique on 60 ns time scale

A small mesa structure (10 /spl mu/m /spl times/ 10 /spl mu/m, 15 nm thick) of intrinsic Josephson junctions in Bi/sub 2/Sr/sub 2/CaCu/sub 2/o/sub 8+/spl delta// is employed to observe the tunneling characteristics and the superconducting gap magnitude by short pulse technique (short pulse interlayer tunneling spectroscopy). In the measurement on 60 ns time scale, the effect of self-heating is almost negligible in the sample, whose resistivity is as small as 10 /spl Omega/cm. In slightly overdoped region, the maximum Josephson current density increases from 0.85 to 2.1 kA/cm/sup 2/ with increasing doping level. The superconducting gap magnitude 2/spl Delta/ decreases from 62 to 37 meV with increasing doping level. The value for 2/spl Delta//k/sub B/T/sub c/ decreases from 8.3 to 5.2 with increasing doping level. These values in slightly overdoped region are smaller than those in optimum and underdoped region.