Microstructure study of Bi/sub 4/Ti/sub 3/O/sub 12/-SrBi/sub 4/O/sub 15/ and Bi/sub 3.25/La/sub 0.75/Ti/sub 3/O/sub 12/-SrBi/sub 4/Ti/sub 4/O/sub 15/ ceramics

TEM study is preformed on mixed-layer type bismuth compounds: Bi/sub 4/Ti/sub 3/O/sub 12/-SrBi/sub 4/T/sub 4/O/sub 15/ (BT-SBTi) and Bi/sub 3.25/La/sub 0.75/Ti/sub 3/O/sub 12/-SrB/sub 4/T/sub 4/O/sub 15/ (BLT-SBTi) ceramics. Meeting the prediction of space group theory, APBs and 90/spl deg/ domain wall are observed by bright- and dark-field imaging in both materials. Besides, other planer defects are found and confirmed to be stacking faults.