Ideal tunneling characteristics in Ba sub 1 minus x K sub x BiO sub 3 point-contact junctions with Au and Nb tips

Journal Article · Sun Nov 25 23:00:00 EST 1990 · Applied Physics Letters; (USA)

DOI:https://doi.org/10.1063/1.104172· OSTI ID:6193560

Huang, Q; Zasadzinski, J F; Gray, K E; Richards, D R; Hinks, D G ^[1]

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1. Materials Science Division, Argonne National Laboratory,Argonne, IL (USA) Science and Technology Center for Superconductivity, Argonne National Laboratory, Argonne, IL (USA)

One important potential application of high-temperature superconductors is for tunnel junctions, especially hysteretic Josephson junctions. Unfortunately, tunnel junctions of oxide superconductors with a useful {Tc}{gt}20 K have exhibited nonideal {ital I}({ital V}) characteristics with a normalized zero-bias conductance, {sigma}{sub {ital s}}/{sigma}{sub {ital n}}(0), of 15--50%. We present data on point-contact junctions of Ba{sub 1{minus}{ital x}}K{sub {ital x}}BiO{sub 3} which clearly demonstrate that these problems are not intrinsic. Using a normal-metal counterelectrode, {sigma}{sub {ital s}}/{sigma}{sub {ital n}}(0) was {lt}1% and {sigma}{sub {ital s}}/{sigma}{sub {ital n}}({ital V}) agreed with the BCS theory by including {ital only} thermal smearing. Using a superconducting Nb counterelectrode, the {ital I}({ital V}) showed very sharp features with evidence of a proximity effect, and {sigma}{sub {ital s}}/{sigma}{sub {ital n}}(0) was {lt}0.2%. These results prove that there is no fundamental limitation for tunnel junctions using this HTS material, and one can anticipate operation of devices with two Ba{sub 1{minus}{ital x}}K{sub {ital x}}BiO{sub 3} electrodes at 15--20 K.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 6193560
• Journal Information: Applied Physics Letters; (USA), Journal Name: Applied Physics Letters; (USA) Vol. 57:22; ISSN APPLA; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
ANL
BARIUM COMPOUNDS
BARIUM OXIDES
BISMUTH COMPOUNDS
BISMUTH OXIDES
CHALCOGENIDES
ELECTRIC CONDUCTIVITY
ELECTRIC CONTACTS
ELECTRICAL EQUIPMENT
ELECTRICAL PROPERTIES
EQUIPMENT
HYSTERESIS
JOSEPHSON EFFECT
JOSEPHSON JUNCTIONS
JUNCTIONS
NATIONAL ORGANIZATIONS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
POTASSIUM COMPOUNDS
POTASSIUM OXIDES
SUPERCONDUCTING JUNCTIONS
SUPERCONDUCTIVITY
TUNNEL EFFECT
US AEC
US DOE
US ERDA
US ORGANIZATIONS