Critical current density and microstructure of YBa sub 2 Cu sub 4 O sub 8

Journal Article · Tue Jan 01 04:00:00 EST 1991 · Journal of Applied Physics; (USA)

DOI:https://doi.org/10.1063/1.347726· OSTI ID:6258954

Miyatake, T; Yamaguchi, K; Wada, T; Suzuki, N; Willis, J O; Yamauchi, H; Koshizuka, N; Tanaka, S ^[1]

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1. Superconductivity Research Laboratory, ISTEC 1-10-13 Shinonome, Koto-ku, Tokyo 135, Japan (JP)

We investigated the intragranular critical current density {ital J}{sub {ital c}} in YBa{sub 2}Cu{sub 4}O{sub 8} prepared by two routes with different oxygen pressures at various temperatures and applied fields. A relationship between the {ital J}{sub {ital c}}'s and the microstructures observed by transmission electron microscopy is discussed. The magnitude of {ital J}{sub {ital c}} for the low oxygen processed sample is higher by a factor of 5 than that for the high oxygen pressure sample. Transmission electron microscopy reveals that the sample prepared at high oxygen pressure shows an almost perfect stacking sequence, but the low oxygen pressure prepared one has a severely distorted structure. We conclude that the difference in {ital J}{sub {ital c}}({ital H}) for the samples must be related to the different microstructures. {ital J}{sub {ital c}} at a fixed magnetic field shows an exponential temperature dependence similar to that seen in other high-{ital T}{sub {ital c}} superconductors. The field dependence is {ital J}{sub {ital c}}{proportional to}{ital H}{sup {minus}{ital n}} with {ital n} between 0.5 and 1.5, and with the {ital n} value becoming larger at higher temperatures. This type of the behavior may arise from the two-dimensional character of YBa{sub 2}Cu{sub 4}O{sub 8}.

• OSTI ID: 6258954
• Journal Information: Journal of Applied Physics; (USA), Journal Name: Journal of Applied Physics; (USA) Vol. 69:1; ISSN 0021-8979; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CRITICAL CURRENT
CRYSTAL STRUCTURE
CURRENTS
ELECTRIC CURRENTS
ELECTRON MICROSCOPY
GRANULAR MATERIALS
HIGH-TC SUPERCONDUCTORS
HYSTERESIS
MATERIALS
MICROSCOPY
MICROSTRUCTURE
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SUPERCONDUCTORS
TEMPERATURE DEPENDENCE
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
TRANSMISSION ELECTRON MICROSCOPY
YTTRIUM COMPOUNDS
YTTRIUM OXIDES