Title :
Effect of ion beam damage and heat treatment on interface-modified junctions
Author :
Park, W.K. ; Lee, H.J. ; Kye, J.I. ; Yun, J.H. ; Lee, S.-M. ; Moon, S.H. ; Oh, B.
Author_Institution :
LG Electron. Inst. of Technol., Seoul, South Korea
fDate :
3/1/2001 12:00:00 AM
Abstract :
We have fabricated Josephson junctions by modifying ramp edges of the base electrodes without depositing any artificial barrier layer. We irradiated the ramp edge surfaces with ion beams and heat-treated them under various conditions prior to the deposition of counter-electrode layers. After patterning the samples into ramp edge junctions using photolithography and ion beam etching, we measured their electrical properties, such as current-voltage characteristics, magnetic field modulation of the critical current, and microwave response. Some showed resistively shunted junction (RSJ)-type current-voltage (I-V) characteristics, while others exhibited flux-flow behavior, depending on the details of interface treatment. Junctions fabricated using optimized conditions showed fairly uniform distribution of junction parameters. Their I-V curves were RSJ-type, also shown by the microwave-induced constant voltage steps. IcRn values of typical RSJ-type junctions were about 0.07 mV at 77 K
Keywords :
Josephson effect; barium compounds; critical currents; flux flow; heat treatment; high-temperature superconductors; ion beam effects; photolithography; sputter etching; superconducting junction devices; superconducting thin films; yttrium compounds; 77 K; IcRn values; Josephson junctions; RSJ-type junctions; YBCO; YBa2Cu3O7; base electrode ramp edge modification; counter-electrode layers; critical current magnetic field modulation; current-voltage characteristics; electrical properties; flux-flow behavior; heat treatment; interface-modified junctions; ion beam damage; ion beam etching; microwave response; microwave-induced constant voltage steps; patterning; photolithography; ramp edge junctions; ramp edge surface treatment; resistively shunted junction-type I-V characteristics; uniform junction parameter distribution; Current measurement; Electrodes; Electromagnetic heating; Etching; Heat treatment; Ion beams; Josephson junctions; Lithography; Magnetic field measurement; Surface treatment;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
