Title :
Nb/AlN/Nb Josephson junctions with high critical current density
Author :
Kleinsasser, A.W. ; Mallison, W.H. ; Miller, R.E.
fDate :
6/1/1995 12:00:00 AM
Abstract :
We have produced Nb/AlN/sub x//Nb Josephson tunnel junctions with the aims of improving the control of critical current density J/sub c/ in the high-J/sub c/ range and exploring the possibility of high-J/sub c/ junctions with low subgap quasiparticle currents. Conventional Nb/AlO/sub x//Nb junction barriers are formed by oxidizing a thin Al overlayer on the Nb base electrode, and precise control of the oxidation process is difficult at low levels of oxygen exposure. The reactivity of Al with N/sub 2/ is very low, and AlN/sub x/ barriers are therefore formed using an N/sub 2/ plasma. We report the fabrication of AlN/sub x/ barrier junctions with J/sub c/ as large as 4 mA//spl mu/m/sup 2/ and compare their properties to Nb/AlO/sub x//Nb ones of similar J/sub c/.<>
Keywords :
Josephson effect; aluminium compounds; critical current density (superconductivity); niobium; oxidation; quasiparticles; AlN/sub x/ barriers; N/sub 2/ plasma; Nb-AlN-Nb; Nb/AlN/sub x//Nb Josephson tunnel junctions; critical current density; fabrication; oxidation; reactivity; subgap quasiparticle currents; Artificial intelligence; Critical current density; Electrodes; Hafnium; Josephson junctions; Niobium; Oxidation; Stability; Thickness control; Zirconium;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
