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

Volume

11

Issue

1

fYear

2001

fDate

3/1/2001 12:00:00 AM

Firstpage

147

Lastpage

150

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. I_cR_n 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; I_cR_n 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;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.919306

Filename

919306