Possible Pining Centers in Transformation-Processed ${\rm Nb}_{3}{\rm Al}$ Superconductors

Transmission electron microscopy and electron backscatter diffraction were used to observe the grain morphologies of transformation-processed superconductors to identify pinning centers. Their grain sizes and stacking fault densities were analysed to determine whether they are correlated with the critical current density . The stacking faults can be seen as planar defects stacked in three orthogonal directions, when the electron beam was parallel with the direction. was not inversely proportional to the grain size, whereas and appear to be correlated with the stacking fault density.