A microstructural study was made of the interfacial boundaries of 1:1 and 1:2 ordered domains in (Ba0.9La0.1)(Mg0.37Nb0.63)O3 by using high-resolution transmission electron microscopy and X-ray diffractometry. Both 1:2 and 1:1 ordered domains were found to coexist in a fully-ordered single grain. Each ordered domain occupied its own region, and the interfaces were atomically sharp and coherent. The wavelength of the superlattice modulation was about 0.47nm in the 1:1 ordered domains, and about 0.71nm in the 1:2 ordered domains. The transition from the 1:2 ordered region to the 1:1 ordered region was clearly seen at the interfaces. These observations supported previously proposed structural models.

H.J.Lee, H.Ryu, H.M.Park, J.H.Paik, S.Nahm, J.D.Byun: Journal of the American Ceramic Society, 1998, 81[6], 1685-8