Grain boundary misorientations and percolative current paths in high-J_c powder-in-tube (Bi,Pb)₂Sr₃Ca₃Cu₃O_x

Grain orientations and grain boundary misorientations in high-J_c, powder-in-tube (PIT) (Bi,Pb)₂Sr₂Ca₂Cu₃O_x (Bi-2223) were determined using electron backscatter Kikuchi diffraction and x-ray microdiffraction. Data collected from over 113 spatially correlated grains, resulting in 227 grain boundaries, show that over 40% of the boundaries are Σ1 or small angle (less than 15°). In addition, 8% of the boundaries are within the Brandon criterion for CSLs (sigma larger than 1 and less than 50). Grain boundary "texture maps" derived from the electron microscope image and orientation data reveal the presence of percolative paths between low energy boundaries.