Electrical transport across grain boundaries in bicrystals of YBa sub 2 Cu sub 3 O sub 7. delta

Conference · Tue Jan 01 00:00:00 EST 1991

OSTI ID:5329130

Larbalestier, D C; Babcock, S E; Cai, X Y; Field, M B; Heinig, N F; Williams, L K; Zhang, N ^[1]; Gao, Y; Merkle, K L ^[2]; Kaiser, D L ^[3]

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1. Wisconsin Univ., Madison, WI (United States). Applied Superconductivity Center
2. Argonne National Lab., IL (United States)
3. National Inst. of Standards and Technology (IMSE), Gaithersburg, MD (United States). Ceramics Div.

The superconducting properties of about 20 bulk-scale flux-grown bicrystals of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} have been measured in order to deduce the nature of the coupling across their grain boundaries. Bicrystals with types of misorientation relationship were studies: (1) {theta} (001) (C-type) and (2) 90{degrees} (010) plus an additional rotation about the a{sub I} {vert bar} c{sub II} axis (P-type). A general trend for a transition from flux pinning (FP) to Josephson Junction (JJ) to resistive (R) behavior was observed as the misorientation angle increased. However, FP character was observed well into the high-angle regime, in particular, for P-type bicrystals, and JJ behavior was observed at as low as 10{degrees} (001). The J{sub ct} values of two bicrystals were increased by a second oxygen anneal. In one case (28{degrees} (001) boundary), extended oxygenation produced a change from JJ to mixed JJ/FP behavior, markedly raising the transport critical current density (J{sub ct}) at all fields. HRTEM has been performed on two of the same bicrystals which were electromagnetically characterized. A thin second phase layer unobservable by conventional TEM was observed in a resistive boundary, whereas no such phase was detected at a JJ boundary. We conclude that the character of the boundary cannot be predicted either from its misorientation angle or the magnitude of its J{sub c}. 10 refs., 6 figs., 1 tab.

• Research Organization: Argonne National Lab., IL (United States)
• Sponsoring Organization: USDOE; National Science Foundation (NSF); USDOE, Washington, DC (United States); National Science Foundation, Washington, DC (United States)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 5329130
• Report Number(s): ANL/CP-74017; CONF-910736-22; ON: DE91018588; CNN: DMR88-09854; DMR89-11332
• Resource Relation: Conference: International conference on materials and mechanisms of superconductivity, Kanazawa (Japan), 22-26 Jul 1991
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BARIUM OXIDES
ELECTRIC CONDUCTIVITY
COPPER OXIDES
YTTRIUM OXIDES
BICRYSTALS
CURRENT DENSITY
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CRYSTAL STRUCTURE
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PHYSICAL PROPERTIES
POLYCRYSTALS
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
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