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High-T{sub c} edge junctions with Y{sub 0.8}Pr{sub 0.2}Ba{sub 2}Cu{sub 2.7}Co{sub 0.3}O{sub 7{minus}{delta}} barrier layers near the metal{endash}insulator transition

Journal Article · · Applied Physics Letters
DOI:https://doi.org/10.1063/1.119117· OSTI ID:508950
; ;  [1]
  1. Conductus Incorporated, Sunnyvale, California 94086 (United States)
We report the use of an epitaxial barrier of Y{sub 0.8}Pr{sub 0.2}Ba{sub 2}Cu{sub 2.7}Co{sub 0.3}O{sub 7{minus}{delta}} in order to study the effect of Pr in the barrier layer. The bulk behavior of this Pr and Co-doped YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} (YBCO) material shows it is just on the insulating side of the metal{endash}insulator transition. We present the temperature dependence of the critical current I{sub c} and the resistance R{sub n} for junctions with 150-, 300-, and 450-{Angstrom}-thick barriers of Y{sub 0.8}Pr{sub 0.2}Ba{sub 2}Cu{sub 2.7}Co{sub 0.3}O{sub 7{minus}{delta}}. The temperature dependence of the critical currents was analyzed within the framework of the proximity effect of de Gennes. The fittings show that the junctions are in the dirty limit with a diffusion constant of D=2.3cm{sup 2}/s and a pair-breaking scattering time of 8.6{times}10{sup {minus}14}s. The value of the diffusion constant is three times lower than the value we have found in the pure 14{percent} Co-doped YBCO barrier, showing that the Pr doping decreases the mean free path in the junction barrier. The presence of the inelastic pair-breaking process was identified as a key issue in the barrier near the metal{endash}insulator transition. {copyright} {ital 1997 American Institute of Physics.}
OSTI ID:
508950
Journal Information:
Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 23 Vol. 70; ISSN APPLAB; ISSN 0003-6951
Country of Publication:
United States
Language:
English