Properties of high-T/sub c/ ramp-edge junctions with a Ga-doped YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// barrier

Author

I-Hun Song ; Eun-Hong Lee ; Insang Song ; Gwangseo Park

Author_Institution

Electron. Mater. Lab., Samsung Adv. Inst. of Technol., Suwon, South Korea

Volume

9

Issue

2

fYear

1999

fDate

6/1/1999 12:00:00 AM

Firstpage

3137

Lastpage

3140

Abstract

We have fabricated high-T/sub c/ ramp-edge junctions with a Ga-doped YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// (YBCO) barrier in the trilayer geometry of YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta///YBa/sub 2/Cu/sub 2.79/Ga/sub 0.21/O/sub 7-/spl delta///YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// on LaAlO/sub 3/ single crystals. Interface resistances of the junctions were drastically reduced by using in-situ RF plasma cleaning treatment. The cross-sectional images of the interface of the junctions were analyzed by high resolution transmission electron microscopy. The temperature dependences of critical currents and junction resistances were consistent with the behavior predicted by the conventional proximity effect. The critical currents of the Ga-doped junctions were less sensitive to the variation of the barrier thickness compared to those of the other junctions. The increase of the barrier resistivity by Ga-doping resulted in an enhancement of the I/sub c/R/sub n/ values, up to 320 /spl mu/V at 60 K.

Keywords

Josephson effect; barium compounds; high-temperature superconductors; proximity effect (superconductivity); superconductor-normal-superconductor devices; yttrium compounds; 60 K; Ga-doped YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// barrier; LaAlO/sub 3/ single crystal substrate; RF plasma cleaning; YBCO trilayer structure; YBa/sub 2/Cu/sub 2.79/Ga/sub 0.21/O/sub 7/; YBa/sub 2/Cu/sub 3/O/sub 7/; critical current; cross-sectional imaging; high-T/sub c/ superconductor; interface resistance; proximity effect; ramp-edge Josephson junction; temperature dependence; transmission electron microscopy; Cleaning; Critical current; Crystals; Electrons; Geometry; Image analysis; Image resolution; Plasma temperature; Radio frequency; Yttrium barium copper oxide;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.783694

Filename

783694