Single-electron tunnelling devices based on intrinsic Josephson junctions in Bi-2212
We fabricated submicron-sized intrinsic Josephson junctions of Bi-2212 by the focused-ion-beam (FIB) etching method. The main result was a reduction of the in-plane junction area to 0.3 m2by direct FIB etching with no degradation in the critical transition temperature (Tc). At the current (I)-voltage (V) characteristic of these stacks, the gap structure and the normal-state resistance are clearly observed by a reduction of the Joule heating. The critical current density is considerably suppressed, the hysteresis and multibranch structure are eliminated and a periodic structure of current peaks appears reproducibly on the I-Vcurves. The period Vof the structure is consistent with the Coulomb charging energy of a single pair, V= e/C, where Cis the effective capacitance of the stack. It is considered that this behaviour originates from the Coulomb blockade of intrinsic Josephson tunnelling in submicron Bi-2212 stacks. We demonstrated the junction operating up to 10 K for the stack with an in-plane size of 0.3 m2and an elementary junction number of 50.
Document Type: Miscellaneous
New Industry Creation Hatchery Centre (NICHe), Tohoku University, Japan
Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Corporation (JST), Japan
Publication date: January 1, 2000