A system for fast time-resolved measurements of c-axis quasiparticle conductivity in intrinsic Josephson junctions of 2212-BSCCO

A wide-band cryogenic amplifier measurement system for time-resolved four-point IV-characteristic measurements on 2212-BSCCO mesa structures is described. We present measurements which demonstrate the importance of self-heating on 50 ns time scales. Such heating is likely to have been very significant in many previously published measurements, where the reported nonlinear IV characteristics have been used to derive superconducting energy gaps.