Critical current density, lower critical field, and flux creep in Ag-sheathed high- J sub c tape of Bi-Pb-Sr-Ca-Cu-O

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

DOI:https://doi.org/10.1063/1.348559· OSTI ID:6000462

Oota, A; Yata, A; Hayashi, K ^[1]; Ohba, K ^[2]

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1. Department of Electrical and Electronic Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi, Aichi 441, Japan (JP)
2. Technical Research and Development Laboratories, Topy Industries Ltd., Akemi-cho, Toyohashi, Aichi 441, Japan (JP)

Initial magnetization curve {ital M}({ital H}) and magnetic relaxation {ital M}({ital t}) were studied on the Ag-sheathed and highly {ital c}-axis oriented tape of Bi-Pb-Sr-Ca-Cu-O with transport {ital J}{sub {ital ct}}=5400 and 2400 A/cm{sup 2} (77 K, {ital H}=0). The {ital J}{sub {ital c}} value, derived from {ital M}({ital H}) curve based on Bean's critical-state model, agrees fairly well with the {ital J}{sub {ital ct}}. The lower critical field {ital H}{sub {ital c}1} for {ital H}{perpendicular}{ital c} axis from {ital M}({ital H}) curve increases with a slope of {minus}0.2 Oe/K as temperature decreases from {ital T}{sub {ital c}}, and it approaches the saturated value of 15 Oe at {ital T}{similar to}0 K. The magnitude is much lower than that for the high-{ital T}{sub {ital c}} superconductors La-Sr-Cu-O and Y-Ba-Cu-O. The creep rate and activation energy {ital U}{sub 0} are evaluated from {ital M}({ital t}) based on the flux creep model. The results show a significant dependence on the measuring process and magnetic field {ital H}. The {ital U}{sub 0} at 5 K for {ital H}=500 Oe ({ital H}{perpendicular}{ital c}) is 0.4 eV for the in-field magnetization (IN) and 0.1 eV for the remanent magnetization (REM), which are larger than those for Bi-based high-{ital T}{sub c} superconductors reported previously. The {ital U}{sub 0} for the IN shows a peak of 0.8 eV around 30 K and then decreases as temperature increases, while a peak in it is weakened for the REM. The {ital U}{sub 0} at {ital H}=30 Oe ({ital H}{perpendicular}{ital c}) for the IN is one order larger than that for 500 Oe and the peak temperature is shifted to the lower temperature ({similar to}10 K).

• OSTI ID: 6000462
• Journal Information: Journal of Applied Physics; (USA), Journal Name: Journal of Applied Physics; (USA) Vol. 69:5; 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
BISMUTH COMPOUNDS
BISMUTH OXIDES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
COATINGS
COPPER COMPOUNDS
COPPER OXIDES
CRITICAL CURRENT
CRITICAL FIELD
CURRENTS
ELECTRIC CURRENTS
ELEMENTS
FILMS
HIGH-TC SUPERCONDUCTORS
LEAD COMPOUNDS
LEAD OXIDES
MAGNETIC FIELDS
MAGNETIC FLUX
MAGNETIC PROPERTIES
MAGNETIZATION
METALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RELAXATION
SILVER
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS