Random telegraph voltage noise in a Bi2Sr2CaCu2O8+x intrinsic Josephson junction

Low frequency noise propel ties have been investigated in mesa-type Bi2Sr2CaCu2O8+x (BSCCO) intrinsic Josephson junction. The junction al ea for this mesa was 160 mu mx40 mum. The mesa showed highly hysteretic current-voltage characteristic at low temperatures, and had seven discrete-resistive-branches. For the noise measurements only at T similar to 36 K, we observed a rapid increase in the noise voltage spectrum over our entire bandwidth. Large random telegraph voltage noises (RTVN) were only detected for low bias current region of the BSCCO mesa for current biased on the 4th (I-b=6.0 mA) and 5th (I-b=5.0 mA) resistive-branches, and also not observed for all of voltage region at 4.2 K and low bias voltage region, from Ist to 3rd resistive-branches, at 36 K. The measured S-V(f) had the Lorentzian frequency dependence, as expected from the Machlup formula for random telegraph signal, The possible origin of the large RTVN may be thermal fluctuation of the "switchback" voltage V-min.