The domain structure of a typical antiferroelectric substance, lead zirconate, is examined in detail fori the first time by electron diffraction and electron microscopy. The 90° and 60° domain configurations can be consistently understood on the basis of the pseudo-cubic unit cell. 180° domains, which are characteristic of the antiferroelectric phase, are observed. The displacement vectors between the domains are determined as ¼[21n], ¼[21̄n] and ¼[02n] (n=0 or 2) by the α-fringe theory for off-Bragg settings. Crystal structure images of the domains reveal how the unit cells connect across the domain boundary. 90° and 180° domains are found in the intermediate phase between the antiferroelectric and the paraelectric phases. The fact that 180° domains are observed is important evidence indicating that the phase is ferroelectric.

Transparent lead lanthanum zirconate titanate (PLZT) ceramics were fabricated from fine powders using an inexpensive two-stage sintering technique. The powders were prepared by hydrolysis from low-cost inorganic precursors. In the two-stage sintering method, uniaxially pressed green pellets were densified to nearly theoretical values in an oxygen gas atmosphere during the first-stage sintering, at 1000°C for 1 h, and then residual, free lead oxide in the pellets was removed by second-stage sintering at 1100°C for 12 h. Transparent ceramic with an average grain size of 1.6 Fm and a porosity of 1.3% was obtained. The transparency and dielectric characteristics of the present samples were compared with those of hot-pressed samples: The study of the polarization-field hysteresis loops of the present samples yielded a remanent polarization of 6.8 FC/m2 and a coercive field of 1.6 kV/cm. The low coercive field of PLZT ceramics could potentially reduce the driving voltage of electrooptic devices in many applications.

(Pb, La)(Zr, Ti)O3 films were prepared by multiple (electro-phoretic deposition/sintering) cycles, using fine crystalline powders, acetone, nitrocellulose and HNO3 as suspensions. Dense, strong films having a final thickness of 15∼25 µm were formed reproducibly on platinum substrates. Due to tight contact between the film and rigid substrate, during firing, lattice constants of sintered films were 0.3∼0.5% longer than those of bulk with the same composition. Reflecting these lattice expansions, the Curie temperature of sintered films shifted to higher temperature as compared to that of bulks with the same composition. All films with the composition 8/65/35 and 9/65/35 are ferroelectric and thus exhibit pyroelectric, and piezoelectric activities. These characteristics of the films are modified from those of the bulk form by crystal lattice distortion.

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