Title :
Investigation of ramp-type Josephson junctions with surface-modified barriers
Author :
Soutome, Y. ; Hanson, R. ; Fukazama, T. ; Saitoh, K. ; Tsukamoto, A. ; Tarutani, Y. ; Takagi, K.
Author_Institution :
Adv. Res. Lab., Hitachi Ltd., Kokubunji, Japan
fDate :
3/1/2001 12:00:00 AM
Abstract :
We have investigated the properties of YBa2Cu3 O7-x ramp-edge Josephson junctions with surface-modified barriers produced by Ar-ion irradiation followed by oxygen annealing. The fabricated junctions displayed RSJ-like I-V characteristics and excellent uniformity. The stray capacitance of the junctions was estimated from the ramp-edge structure. The junction capacitance was obtained by subtracting the stray capacitance from the shunting capacitance. We estimated the barrier thickness from the junction capacitance, and found that the critical current density of the junction increased exponentially with decreasing barrier thickness. The relative dielectric constant of the barriers ranged from 13 to 18
Keywords :
Josephson effect; annealing; barium compounds; capacitance; critical current density (superconductivity); high-temperature superconductors; ion beam effects; permittivity; sputter etching; superconducting junction devices; superconducting thin films; yttrium compounds; Ar-ion irradiation; RSJ-like I-V characteristics; YBa2Cu3O7-x ramp-edge Josephson junctions; YBa2Cu3O7; barrier thickness; critical current density; junction capacitance; oxygen annealing; ramp-edge structure; relative dielectric constant; shunting capacitance; stray capacitance; surface-modified barriers; uniformity; Annealing; Capacitance; Dielectric constant; Etching; Fabrication; High temperature superconductors; Josephson junctions; Laboratories; Plasma temperature; Yttrium barium copper oxide;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
