1,157 research outputs found
Orientation and film thickness dependencies of (100)- and (111)-oriented epitaxial Pb(Mg1/3Nb2/3)O3 films grown by metal organic chemical vapor deposition
Abstract(100)- and (111)-oriented epitaxial Pb(Mg1/3Nb2/3)O3 films with 500 and 1300 nm in thickness were grown by metal organic chemical vapor deposition. Remained strain was almost relaxed because the crystal structure of the films was almost the same as that of bulk Pb(Mg1/3Nb2/3)O3. Relative dielectric constant showed the maximum value against the temperature that depended on the measurement frequency. Maximum relative dielectric constant, εr(max.), and the temperature showing εr(max.), T(max.), decreased and increased with the frequency, respectively, are in good agreement with reported data for the bulk. εr(max.) and T(max.), respectively increased and decreased with the film thickness and (111)-oriented films showed larger value than that of the (100)-oriented one. Ferroelectricity was observed for all films up to 297 K and monotonously decreased with increasing temperature. Saturation polarization value increased with the film thickness and (111)-oriented films showed larger value than (100)-oriented ones. On the other hand, the coercive field decreased with increasing film thickness, but was almost independent with the film orientation
Epitaxial PZT films for MEMS printing applications
Films of piezoelectric and ferroelectric oxides have been widely investigated for various applications, including microelectromechanical systems (MEMS) for printing. Pb(Zr,Ti)O3 is of particular interest due to its excellent piezoelectric properties. Control of the density, crystalline orientation, and compositional uniformity is essential to obtain these properties. In this article, we review recent progress on the fabrication of epitaxial Pb(Zr,Ti)O3films, in which the aforementioned control can be achieved. We discuss the different approaches used for the deposition of the epitaxial piezoelectric layer as well as the achieved degrees of the epitaxy. Furthermore, the integration of these piezoelectric layers in MEMS and the corresponding performance are discusse
Ferroelectric property of an epitaxial lead zirconate titanate thin film deposited by a hydrothermal method
Deposition of thin films via hydrothermal method has various advantages: low deposition temperature, high purity, deposition on a three-dimensional structure,and a large thickness. Although an epitaxial lead zirconate titanate (PZT) thin-film deposition has been reported, the ferroelectric measurement has not been conducted due to the peel-off morphology of the film. The current paper investigates the improvement of an epitaxial PZT thin film deposited via a hydrothermal method. By adjusting the position at which the substrate was suspended in the solution, smooth morphology surface was successfully obtained. As a bottom electrode, a 200-nm SrRuO3 thin film was deposited on SrTiO3 single crystals, and the PZT thin film was deposited on SrRuO3. The remanent polarization 2Pr and coercive electric field for PZT on SrRuO3/SrTiO3 (001) were 17.1 μC/cm2 and 36 kV/cm, respectively, and those of PZT on SrRuO3/SrTiO3 (111) were 32.7 μC/cm2 and 59 kV/cm, respectively. The reason for large imprint electrical field, 91 kV/cm and 40 kV/cm for each film, was unclear at this stage, although it is associated with self-alignment poling direction. This self-alignment poling direction was confirmed via scanning nonlinear dielectric microscopy and is thought to have been related to the deposition mechanism
Domain distributions in tetragonal Pb(Zr,Ti)O3 thin films probed by polarized Raman spectroscopy
We have investigated polarized Raman spectra of (001)/(100)-oriented tetragonal epitaxial Pb(ZrxTi1–x)O3 (PZT) thin films (x=~0.35) in which the volume fraction of the polar c domain is systematically varied from 4% to 96%. From polarization analyses using high epitaxial quality films, we have successfully isolated the A1 and B1 phonons from the E phonons, thus offering a distinctive evaluation of the c domains. As increasing c-domain volume, the A1(TO) modes linearly increase in their intensity. A remarkable correlation is found between the A1(1TO)-mode intensity and the c-domain volume for PZT films. We suggest that this correlation as well as the A1(1TO)-mode intensity provide a simple and useful probe for characterization of c-domain volume and ferroelectric properties in PZT-based devices
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