Intrinsic tunneling spectroscopy of Bi2Sr2CaCu2O8+δ:: The junction-size dependence of self-heating

The self-heating effect on intrinsic tunneling spectra (ITSs) is investigated using stacks of intrinsic Josephson junctions (IJJs) in near optimally doped Bi2Sr2CaCu2O8+delta crystals. The area of the stacks S ranges from 12 down to 0.16 mu m(2). For IJJs with larger S, ITSs are distorted by self-heating, but become progressively less size dependent as S decreases down to submicrometer level. Analysis based on the ballistic phonon model of Krasnov indicates a temperature rise of similar to 5 K for the smallest junctions at the bias voltage corresponding to the conductance peak. A brief comparison between the ITSs and spectra from other techniques is presented.