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(100)/(001)-oriented 2 μm-thick Pb(Ti, Zr)O3, films with the Zr/(Zr + Ti) ratio of 0.39 and 0.50 were prepared by metalorganic chemical vapor deposition. The volume fraction of (001)-oriented domain, Vc, was controlled by selecting the kinds of substrates with different thermal expansion coefficient. The effective piezoelectric constant increased up to 310 pm/V with decreasing the Vc and tetragonality (lattice parameter ratio of c axis to a axis) determined by the decrease of the Zr/(Zr + Ti) ratio. Observed large piezoelectric response was considered to be mainly contributed by the extrinsic effect, such as the 90o domain switching. These experimental inputs suggest the new concept for enhancement of the piezoelectric properties. [ABSTRACT FROM AUTHOR]

Epitaxial Pb(Zr,Ti)O3 (PZT) thick films of 2.0–3.0 μm thickness were grown at 600 °C on (100)cSrRuO3∥(100)SrTiO3 and (100)cSrRuO3∥(100)LaNiO3∥(100)CaF2 substrates by pulsed-metal organic chemical vapor deposition. All films showed (100) and/or (001) orientations with tetragonal symmetry. It was found that there is an almost linear relationship between the estimated thermal strain from the deposition temperature to the Curie temperature and the volume fraction of (001) orientation in the mixture of (100) and (001) orientations for the films on both substrates. Consequently, the perfectly (001)-oriented, i.e., polar-axis-oriented, PZT thick films were obtained on CaF2 with the Zr/(Zr+Ti) ratio from 0.20 to 0.40. Moreover, the lattice parameter of a- and c-axes and their ratio (c/a) of those polar-axis-oriented films were almost the same as the reported data for the powder, suggesting that the large strain is not remaining in those films. The relative dielectric constant ([variant_greek_epsilon]r) of the polar-axis-oriented Pb(Zr0.35Ti0.65)O3 thick film on CaF2 was 180 at 1 kHz, which is lower than that of (100)/(001)-oriented thick films on SrTiO3 but almost agrees with the theoretically calculated value for the c-axis of PZT single crystals. Well saturated polarization-electric-field hysteresis loops with a good square shape were observed for the polar-axis-oriented thick films, and the saturation polarization and the coercive field values were 74 μC/cm2 and 64 kV/cm, respectively. These data clearly show that the electrical properties of the polar-axis-oriented epitaxial thick films are similar to the theoretical predictions for PZT single crystals. [ABSTRACT FROM AUTHOR]

Epitaxial (100)/(001)-oriented tetragonal Pb(Zr,Ti)O3 films above 1 μm thick were grown on (100)SrTO3 substrates by pulsed metal organic chemical vapor deposition, and the films with Zr/(Zr+Ti) ratios up to 0.43 were found to have a strain-relaxed domain structure. The domain structure determined by the volume fraction of (001) orientation (mainly decided by the thermal strain above the Curie temperature) and the lattice parameters dependent on the Zr/(Zr+Ti) ratio are explained by a geometrical model consistent with previous results for PbTiO3 films [J. Appl. Phys. 104, 064121 (2008)]. [ABSTRACT FROM AUTHOR]

(100)/(001)-oriented epitaxial PbTiO3 films thicker than 1 μm were grown on various types of substrates by chemical vapor deposition. The domain structures of these films with different volume fractions of (001) were investigated. Domain structures, consisting of (100)/(001)-oriented domains, were observed regardless of the type of substrate. However, the tilting angles of the a- and c-domains from the surface normal linearly changed with the volume fraction of the (001) orientation. These results suggest that the volume fraction of the (001) orientation is crucial in identifying the domain structure of PbTiO3 thick films. [ABSTRACT FROM AUTHOR]