CRITICAL-CURRENT DENSITY ON BI(2212) SAMPLES WITH A NEEDLE-LIKE GRAINMICROSTRUCTURE

In an early work we have reported that a simplified version of the mel t-textured growth (MTG) process on Bi(2212) leads to a microstructure consistent in superconducting needle-like grains. The size of the resu lting needles is about 1.5 mm in length and 100 mu m in diameter. The internal structure of these needles seems to be the result of the melt ing of the typical Bi(2212) plate-like grains along a longitudinal axe , so the superconducting ab plane must run continuously along the need le length. The critical temperature, deduced from the magnetisation cu rve, is about 91K. Now, we have performed critical current density and resistivity measurements on single needle-like grains to ensure its p ractical application possibilities for making superconducting Ag-sheat ed wires and tapes. The critical current density at 77.4 K in absence of magnetic field of a single needle is about 2500 A/cm(2).