The effect of microstructure on the electrical properties of the YBCO interface-engineered Josephson junctions.

Journal Article · Fri Jan 01 04:00:00 EST 1999 · Physica C

DOI:https://doi.org/10.1016/S0921-4534(99)00028-3· OSTI ID:942380

Huang, Y; Merkle, K L; Moeckly, B H; Char, K

The microstructure of interface engineered ramp-edge Josephson junctions in YBCO has been studied by transmission electron microscopy (TEM). The junctions are distinctly different from the structures found in heterophase SNS junctions. This structural difference can be directly related to the improved electrical properties of interface engineered junctions. The plasma treatment used in the interface engineering method forms a continuous barrier layer of 2 to 3 nm in thickness, much thinner than the deposited heterophase layers in SNS junctions. The layer, which separates the two YBCO layers, is crystalline, but has a crystal structure different from YBCO. The main factors responsible for the improved junction properties and their good reproducibility are: small barrier thickness, small thickness variation, weak interfacial strain fields, flat and nearly defect-free barrier/YBCO interfaces and good epitaxy of the second YBCO layer with few defects. Possible mechanisms for the formation of the large junction resistance are discussed.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: ER; NSF
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 942380
• Report Number(s): ANL/MSD/JA-30825
• Journal Information: Physica C, Journal Name: Physica C Journal Issue: 1999 Vol. 314; ISSN 0921-4534; ISSN PHYCE6
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

36 MATERIALS SCIENCE
BARIUM OXIDES
COPPER OXIDES
CRYSTAL STRUCTURE
DEFECTS
ELECTRICAL PROPERTIES
ENGINEERING
EPITAXY
INTERFACES
JOSEPHSON JUNCTIONS
LAYERS
MICROSTRUCTURE
PLASMA
STRAINS
THICKNESS
TRANSMISSION ELECTRON MICROSCOPY
YTTRIUM OXIDES