Modulated Structure and Antiphase Boundary in (Ca<SUB>0.4</SUB>, Nd<SUB>0.6</SUB>)<SUB>1.54</SUB>Ti<SUB>2</SUB>O<SUB>6</SUB> Microwave Dielectrics

High resolution electron microscopy (HREM) observation with the multislice simulation was performed in order to analyze the structure of Ca-Nd-Ti-O microwave dielectrics which have recently been synthesized.The detailed structure that was predicted by X-ray diffractmetry and Rietvelt analysis was the structure in which the lattice vacancies exist selectively in the (002) plane of perovskitelike unit cells.We confirmed the predicted structure by comparing the HREM images with simulated images. We also revealed the antiphase boundary (APB) caused by the displacement of the (002) defective planes.