Microstructure Study of BaTiO_3 Ceramics Using Convergent Beam Electron Diffraction

摘要

The nanoscale local structure of core-shell structured BaTiO_3 grains with a nonuniform dopant distribution was studied by convergent beam electron diffraction. The direct measurements of the variation of lattice parameter in an individual BaTiO_3 grain were achieved. It was found that the lattice parameter continuously increased from inside the grain core to the grain shell and there was no discontinuity at the core/shell interface. The increasing gradient of c-axes was slightly smaller than that of a-axes, suggesting that the perovskite unit cell in the grain shell has lower tetragonality.