We have used in situ x-ray diffraction to measure strain curves of single crystals of 92% Pb(Zn1/3Nb2/3)O3–8% PbTiO3 poled in the 〈001〉 direction. We observed shifts in the (002) and (330) peaks as functions of applied voltage (in the 〈001〉 direction), thereby measuring the crystallographic strain. Our measurements confirm that the high strains observed using macroscopic methods reflect microscopic strains in the crystal lattice. By watching the disappearance of a rhombohedral splitting in the (330) peak, we also find direct evidence that the field-induced phase transition reported by S.-E. Park and T. R. Shrout [J. Appl. Phys. 82, 1804 (1997)] occurs between a pseudorhombohedral and tetragonal crystal structure.

In situ x-ray diffraction studies were performed on the PLSnZT antiferroelectric–ferroelectric phase switching ceramic and polycrystalline powder. The crystallography of both the antiferroelectic and electric-field-induced ferroelectric phases were determined for the approximate composition of Pb0.98La0.02(Zr0.55Sn0.33Ti0.12)0.995O3. A preferred antiferroelectric domain structure has been identified and possible mechanisms responsible for the domain structure are presented. A single tetragonal phase has been identified for the room temperature zero-field antiferroelectric material with unit cell dimensions a=4.107 Å and c=4.081 Å. An electric field-induced structure developing at the antiferroelectric–ferroelectric switching field has also been observed and determined to be of rhombohedral symmetry with a=4.105 Å and θ=89.85° indicating a volume increase of 0.49% for the tetragonal–rhombohedral transition.

Electric field induced changes in the x-ray diffraction pattern of nylon 11 films containing a mixture of the alpha and gamma crystal phases are presented. These changes indicate an orientation of crystallites such that dipoles are aligned in the direction of the poling field. Correlation between this crystal orientation and piezoelectric activity was observed.

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Ferroelectric hysteresis of a copolymer of vinylidene fluoride with tetrafluoroethylene and of uniaxially stretched polyvinylidene fluoride has been observed at 60 Hz at room temperature. The measured remanent polarization of the copolymer was in good agreement with a calculated value using a frozen dipole model and measured piezoelectric coefficients. The dielectric constant for the copolymer has been measured at 1000 Hz as a function of temperature. Also, a set of copolymer films of varying thickness were poled above the melt temperature and their piezoelectric stress coefficients g31 were measured as a function of the poling field. These measurements indicate that the copolymer, when poled above the melt temperature, exhibits bulk polarization. These results suggest that this copolymer is ferroelectric and that poling aligns the dipoles in the β crystal phase of the material.