Diffraction Microscopy using 20-kV Electron Beam for Multi-Wall Carbon Nanotubes

The spatial distribution of flux pinning centers in YBa2Cu3O7 (YBCO) coated conductors significantly affects the conductive properties. Nanoparticles acting as pinning centers can be intentionally introduced into the structure by chemical doping. In this study, a Dy-doped YBa2Cu3O7-x coated superconductor was investigated and the particle composition was found to be as (YsDy1-s)2Cu2O5 with s ~0.6. A tomographic tilt series was acquired using a scanning transmission electron microscope (STEM) to determine the 3-D distribution of nanoparticles. In the investigated sample area, 71 particles were located with a particle size distribution ranging between 13 and 135 nm. The distribution uniformity and size of the particles appeared to be dependent on the grain boundary network structure. Large particles were observed to be located on grain boundaries indicating that fast grain boundary diffusion may determine the particle size.