Current-voltage characteristics of Bi-2212 intrinsic Josephosn junctions, unfortunately, are greatly affected by joule heating, due to the very low thermal conductivity of the Bi-2212 material. To reduce this effect, we used pulse current measurement technique. The current pulses were supplied from a home-built pulse generator with the pulse width of 250 nsec and the duty ratio of 2.5×10 -5 . The pulse shapes of the input current and the junction voltage were monitored with an analog storage

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... illoscope. The junction voltage was determined at the 200 ns from a triggered point. At 77 K, it was found that a quasiparticle curve in the subgap region could be approximated by a linear resistance.