Features of Ferroelectric States in the Simple-Perovskite Mixed-Oxide System (1-x)Pb(Zn^sub 1/3^Nb^sub 2/3^)O^sub 3^-xPbTiO^sub 3^ with Lower Ti Contents

A mixed-oxide system (1 - x)Pb(Zn...Nb...)O...-xPbTiO..., which has a simple perovskite structure, has been reported to exhibit remarkable piezoelectric responses for 0 < x ≤ 0.08. To understand the ferroelectric states for 0 < x < 0.10, the crystallographic features of plate-shaped single crystals with various sample orientations have been examined by transmission electron microscopy. Owing to both the bending of specimens and the complicated nanometer-scale domain structures, it was difficult to obtain a contrast reversal due to the failure of Friedel's law. In some cases, however, it was possible to analyze the ferroelectric domain structures of the sample. Although the typical 109... domain structure of the ferroelectric rhombohedral state was found for x = 0.02, as a major feature in [110] ...-oriented single crystals, the ferroelectric states for 0 < x ≤ 0.08 were found to be characterized by an assembly of nanometer-scale polar (NP) domains with rhombohedral symmetry. In [210] ...-oriented crystals, on the other hand, the so-called MC state with monoclinic symmetry was present for x ... 0.08. Furthermore, on the basis of in-situ observation, the evolution of a maze-pattern domain structure in the MC state upon cooling from the paraelectric state occurs via a local flip-flop between two polarization vectors, which are nearly parallel to the ... directions. It is likely that this behavior is directly associated with the ultrahigh piezoelectric deformations found for x ... 0.08. (ProQuest: ... denotes formulae/symbols omitted.)