Transmission electron microscopy study on ferroelectric domain structure in SrBi2Ta2O9 ceramics

A transmission electron microscopy investigation has been conducted on the domain structure in ${\mathrm{SrBi}}_{\mathrm{2}}{\mathrm{Ta}}_{\mathrm{2}}{\mathrm{O}}_{\mathrm{9}}$ ceramics. From the 90° rotation relationship of the electron diffraction pattern of the [001] zone axis, a 90° domain wall can be confirmed. It is due to the failure of Friedel’s law that the contrast of a 180° domain wall can be identified. The antiphase boundary can be seen clearly in the dark-field image, which is taken by the (300) superlattice reflection. The 90° domain wall, as well as antiphase the boundary (APB), has an irregular configuration. The APB combined with the 90° domain wall is also identified.