Critical current properties of screen-printed Ag-Bi2223 tapes

Critical current densities J/sub c/ (T,B,/spl theta/) were investigated on screen-printed, c-axis-oriented Ag-Bi2223 mono-layer tape, at temperatures between 55 and 77 K in fields up to 8T as a function of field angle /spl theta/ between B and c axis. At temperatures T/spl les/30 K, a shift of a peak angle from /spl theta/=90/spl deg/ (i.e., B/spl perp/c axis) occurs in the J/sub c/ vs. /spl theta/ curve accompanied by an additional asymmetry. Such anomalies are explained by the history effect in the field dependence of J/sub c/ for B/spl par/c axis ascribed to the grain-boundary weak links, on the assumption that J/sub c/ is dominated by the field component B/spl par/=Bcos/spl theta/ parallel to the c axis. At elevated temperatures, disappearance of the history effect results in a perfectly symmetrical angular dependence of J/sub c/ with a peak at /spl theta/=90/spl deg/. An increase in the number of ceramic layers for the screen-printed tape does not cause significant influence on critical current properties.