Critical current density on Bi(2212) samples with a needle-like grain microstructure

Abstract

In an early work we have reported that a simplified version of the melt-textured growth (MTG) process on Bi(2212) leads to a microstructure consistent in superconducting needle-like grains. The size of the resulting needles is about 1.5 mm in length and 100 μ in diameter. The internal structure of these needles seems to be the result of the melting of the typical Bi(2212) plate-like grains along a longitudinal axe, so the superconducting ab plane must run continuously along the needle length. The critical temperature, deduced from the magnetisation curve, is about 91K. Now, we have performed critical current density and resistivity measurements on single needle-like grains to ensure its practical application possibilities for making superconducting Ag-sheated wires and tapes. The critical current density at 77.4 K in absence of magnetic field of a single needle is about 2500 A/cm2.