Effect of grain alignment and processing temperature on critical currents in YBa sub 2 Cu sub 3 O sub 7 minus. delta. sintered compacts

Journal Article · Sun Jul 01 00:00:00 EDT 1990 · Journal of Materials Research; (USA)

DOI:https://doi.org/10.1557/JMR.1990.1368· OSTI ID:6493118

Tkaczyk, J E; Lay, K W ^[1]

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1. GE Corporate Research and Development, Schenectady, New York (USA)

Magnetically aligned YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} ceramics show resistivities approaching that of single crystals and improved transport critical currents in a magnetic field. Reduced microcracking and increased transport along the ab-plane are believed responsible for the improved performance over non-aligned ceramics. Aligned and non-aligned samples were prepared in parallel using a range of sintering and annealing temperatures. A rapid rise in density for samples sintered above 900 C in oxygen is accompanied by rapid grain growth, improved alignment, a drop in the room temperature resistivity and an increase in the critical current. The presence of low melting point (i.e., Ba-Cu-O rich) phases at grain boundaries is believed responsible for the rapid densification. However, the presence of this phase does {ital not} appear to be the most important factor limiting {ital J}{sub {ital c}}. A high temperature oxygen anneal at 900 C improved performance as compared to anneals at 500 C possibly due to the removal of carbon. For aligned samples sintered at 980 C, critical currents are over 200 A/cm{sup 2} at 77 K, 1/4 tesla, and room temperature resistivities are below 350 {mu}{Omega}-cm.

• OSTI ID: 6493118
• Journal Information: Journal of Materials Research; (USA), Vol. 5:7; ISSN 0884-2914
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM OXIDES
CRITICAL CURRENT
COPPER OXIDES
YTTRIUM OXIDES
ALIGNMENT
ELECTRIC CONDUCTIVITY
GRAIN GROWTH
HIGH-TC SUPERCONDUCTORS
MAGNETIC FIELDS
SINTERING
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
CHALCOGENIDES
COPPER COMPOUNDS
CURRENTS
ELECTRIC CURRENTS
ELECTRICAL PROPERTIES
FABRICATION
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
360204* - Ceramics
Cermets
& Refractories- Physical Properties