Title :
Parametric Characterization and Macroscopic Quantum Tunneling of
Josephson Junctions
Author :
Hao Li ; Gang Li ; Jianshe Liu ; Tiefu Li ; Wei Chen
Author_Institution :
Dept. of Micro/Nanoelectron., Tsinghua Univ., Beijing, China
Abstract :
Parameters of Nb/AlOx/Nb Josephson including its critical current and capacitance which determine the dynamic energy consumption and speed of the superconducting electronics have been measured. The critical current of a 22 × 22 μm2 junction is 1801 ± 52 μA calculated from the dependent curve between the lifetime of zero-voltage and switching current. The specific capacitance is 0.051 ± 0.008 pF/μm2 obtained by observing Fiske self-resonant step when applied several Gauss magnetic field. Critical current distributions had been measured as a function of temperature from 900 mK to 40 mK. The distribution widths become independent of temperature below 200 mK, which indicates the transition between thermal activation and macroscopic quantum tunneling of junction phase.
Keywords :
Josephson effect; aluminium compounds; critical currents; niobium; type II superconductors; Fiske self-resonant step; Josephson junctions; Nb-AlOx-Nb; critical current distributions; distribution widths; dynamic energy consumption; macroscopic quantum tunneling; magnetic field; parametric characterization; specific capacitance; superconducting electronics; switching current; temperature 900 mK to 40 mK; thermal activation; zero-voltage lifetime; Critical current density (superconductivity); Josephson junctions; Junctions; Niobium; Superconducting integrated circuits; Temperature measurement; Tunneling; Critical current; Josephson tunneling junction; fiske self-resonant step; macroscopic quantum tunneling;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
DOI :
10.1109/TASC.2014.2349900