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Thin films of Sr(Zr,Ti)O3 were investigated as buffer layers to induce tensile strain in ferroelectric thin films such as PbTiO3 and Pb(Zr,Ti)O3 to control the domain structure. By tuning the composition of Sr(Zr,Ti)O3, (100)-oriented PbTiO3 and Pb(Zr,Ti)O3 films were obtained, revealing that tensile strain was introduced into the thin films by the lattice of the buffer layer. We propose a methodology for the successive control of tensile stress, which is useful for understanding and controlling the domain structures of ferroelectric films that result in the ferroelectric and piezoelectric properties of ferroelectric thin films. [ABSTRACT FROM AUTHOR]

Background: People with schizophrenia have a lower colorectal screening rate than the general population. A previous study reported an intervention using case management to encourage colorectal cancer screening for patients with schizophrenia in psychiatric outpatient settings. In this feasibility study, we developed provider-level implementation strategies and evaluated the feasibility of conducting a definitive trial in terms of the penetration of the intervention assessed at the patient level. Additionally, we examined the fidelity of strategies to implement the intervention at the provider level in a routine clinical psychiatric setting. Methods: This was a multicenter, single-arm feasibility study with medical staff at psychiatric hospitals in Japan. The provider-level implementation strategies developed in this study included three key elements (organizing an implementation team appointed by the facility director, interactive assistance using a clear guide that outlines who in the hospital should do what, and developing accessible educational materials) to overcome major barriers to implementation of the intervention and four additional elements (progress monitoring, joint meetings and information sharing among participating sites, adaptation of encouragement methods to specific contexts, and education of on-site staff), with reference to the elements identified in the Expert Recommendations for Implementing Change (ERIC). The feasibility of the strategies was evaluated by the proportion of patients who were eligible for encouragement (patients with schizophrenia aged 40, 50, or 60) who received encouragement. We set the goal of providing encouragement to at least 40% of eligible patients at each site. Results: Two public and four private psychiatric hospitals in Okayama and Shimane prefectures participated in this study. Regarding fidelity, all elements of the strategies were conducted as planned. Following the procedures in the guide, each team prepared and provided encouragement according to their own facility and region. Penetration, defined as the proportion of eligible patients who received encouragement, ranged from 33.3 to 100%; five of the six facilities achieved the target proportion. Conclusions: The provider-level implementation strategies to implement encouragement were feasible in terms of penetration of the intervention assessed at the patient level. The results support the feasibility of proceeding with a future definitive trial of these strategies. Trial registration: jRCT, jRCT1060220026. Registered on 06/04/2022. [ABSTRACT FROM AUTHOR]

A 30-nm-thick epitaxial tetragonal (100)/(001) Pb(Zr0.22Ti0.78)O3 (PZT) thin film was grown at 600 °C on (001) KTaO3 (KTO) single-crystal substrate by metalorganic chemical vapor deposition. The a/c domain structure in the PZT film was analyzed in detail at room temperature by synchrotron x-ray diffraction (XRD) and piezoresponse force microscopy techniques. The temperature dependence of the crystal structure was investigated by XRD reciprocal space mapping and in-plane grazing incidence XRD. The PZT films were grown on KTO substrates under compressive strains from 700 °C to room temperature. This compressive strain gave rise to a perfect (001) orientation below a Curie temperature (TC) of ∼520 °C. An in-plane a-axis lattice parameter for the c domain kept the same value as that of the substrate lattice up to 350 °C despite the ferroelectric transition. Nucleation of the a domain started at around 350 °C. The formation of the a domain released the strain for the in-plane a-axis lattice parameter, as confirmed by in-plane analysis of the crystal structure. The results revealed that the in-plane average surface area of the PZT unit cell continued to match that of the KTaO3 substrate from 700 °C to room temperature, regardless of the domain structure evolution. [ABSTRACT FROM AUTHOR]

In this study, the ferroelectric phase of PbTiO3 (PTO) thin films was grown on cubic single-crystal KTaO3 (KTO) substrates using metal–organic chemical vapor deposition. X-ray diffraction (XRD) was used to reveal an a1/a2 domain structure, which remained unchanged down to a film thickness of 2 nm. The a1 and a2 polydomains do not have a simple tetragonal symmetry because aa∥ and aa⊥ do not have the same values. The crystallographic tilt angle, α, is defined based on the rotation angle of the PTO lattice with respect to the cubic phase of KTO substrates. The in-plane tetragonal distortion (ca∥/aa∥) and α decreased with the decrease in the film thickness, following the in-plane tetragonal geometric equation: α = tan − 1 ( c a ∥ a a ∥ ) − 45 ° . The isotropic tensile strains induced in-plane polarization directions along the [100] and [010] axes of the substrates. These axes are formed via the a1/a2 polydomain of the tetragonal-like phase. Moreover, synchrotron in-plane grazing incidence XRD and piezoelectric force microscopy were used to reveal the thickness dependency of the periodic domain width of the ferroelastic a1/a2 domain. The periodic domain width in the PTO films decreased, following Kittel's law, with the reduction in the film thickness. [ABSTRACT FROM AUTHOR]

Electric-field- and stress-induced phase transformations were investigated in polycrystalline 0.5 mol. % Mn-doped (1-x)(Bi1/2Na1/2)TiO3-x(Bi1/2K1/2)TiO3 (x=0.1, 0.2). To characterize the effect of electric field and stress on the stability of the ferroelectric and relaxor states, polarizationand current density-electric field curves, as well as the stress-strain response as a function of temperature were characterized. Analogous to the observed electrical behavior, the macroscopic mechanical constitutive behavior showed a closed hysteresis at elevated temperatures, indicating a reversible stress-induced relaxor-to-ferroelectric transformation. The electrical and mechanical measurements were used to construct electric field-temperature and stress-temperature phase diagrams, which show similar characteristics. These data show that a mechanical compressive stress, similarly to an electric field, can induce long-range ferroelectric order in a relaxor ferroelectric. [ABSTRACT FROM AUTHOR]

Epitaxial (100)/(001)-oriented Pb(ZrxTi1−x)O3 [PZT] films were grown at 700 °C on (100)KTaO3 single crystal substrates by pulsed metalorganic chemical vapor deposition. We investigated the influence of the cooling condition on the ferroelastic domain structure for PZT films under compressive and tensile strains. Under compressive strain, the c-domain fraction (Vc) was not strongly influenced by the cooling rate. On the other hand, changing the cooling rate caused a significant change in Vc in the PZT films grown under tensile strain. In addition, a post-annealing step at a certain temperature below the Curie temperature promoted the formation of a c-domain in the a1/a2-domain. These results indicate the need to effectively time the formation of the c-domain in the a1/a2-domain, which is governed by the growth kinetics. The ferroelastic domain structure under tensile stress is determined by the growth kinetics, while a slow cooling rate leads to a thermodynamically stable domain structure. [ABSTRACT FROM AUTHOR]

Epitaxial PbTiO3 (PTO) thin films were deposited on different single crystal (100)KTaO3 [KTO], (110)DyScO3 [DSO], (110) GdScO3 [GSO] and (001)SrTiO3 [STO] substrates. Temperature dependence of the lattice parameters and the domain structure showed a systematic change with misfit strains (Sm) of PTO films, explored by high-resolution X-ray diffraction measurements. Fully (001)-orientation films on STO and fully (100)-orientation films on KTO substrates were confirmed, and the elevated phase transition temperature (Tc) was confirmed in PTO films induced by both large compressive (STO) and tensile strains (KTO). While, for PTO films grown on GSO substrates with small tensile strains, Tc is similar to the powder data. And, ferroelastic domain structure changed from (100)-orientation to (100)/(001)-orientations was observed during decreased temperature. The temperature dependence of domain structures PTO films with the different Sm are in good agreement with thermodynamic calculation for the temperature–Sm diagram of ferroelastic domain structure. [ABSTRACT FROM AUTHOR]

Spatially resolved time and voltage-dependent polarization dynamics in PbTiO3 thin films is explored using dynamic piezoresponse force microscopy (D-PFM) in conjunction with interferometric displacement sensing. This approach gives rise to 4D data sets containing information on bias-dependent relaxation dynamics at each spatial location without long-range electrostatic artifacts. To interpret these data sets in the absence of defined physical models, we employ a non-negative tensor factorization method which clearly presents the data as a product of simple behaviors allowing for direct physics interpretation. Correspondingly, we perform phase-field modeling finding the existence of 'hard' and 'soft' domain wall edges. This approach can be extended to other multidimensional spectroscopies for which even exploratory data analysis leads to unsatisfactory results due to many components in the decomposition. [ABSTRACT FROM AUTHOR]

Domain structures of epitaxial PbTiO3 films grown on (100)cSrRuO3//(100)SrTiO3 substrates by metalorganic chemical vapor deposition were investigated by x-ray diffraction (XRD) and piezoresponse force microscopy (PFM) techniques. It was found that with increasing film thickness, the domain structure changed from simple (001) polarization orientation to a complicated mixture of (001) and (100) orientations. PFM mappings showed that in the thicker films (∼1100 nm), the zigzag (001)/(100) domain boundaries made an angle of approximately 87° instead of 90° typically observed in (001)/(100) domain patterns in thinner (<300 nm) films. Full-relaxed tilting angle θ1 + θ2 + θ3 = 3.4° obtained from cross-sectional profile analysis of topological step-terrace structure was in good agreement with 3.4° and 3.6° angle values obtained from XRD measurements and theoretical prediction, respectively. [ABSTRACT FROM AUTHOR]

Epitaxial (1-x)BaTiO3-xBi(Mg0.5Ti0.5)O3 films with x = 0 - 0.9 were grown on (111)cSrRuO3//(111)SrTiO3 substrates by pulsed laser deposition (PLD). Plotting the temperature where dielectric constant reaches a maximum {T[&eh;r(max.)]} versus Bi(Mg0.5,Ti0.5)O3 content present minimum at x = 0.1. On the other hand, the remanent polarization (Pr) and the effective transverse piezoelectric constant [d33(eff.)] showed minimum at 0.1 and 0.2, respectively, but increased with the increase of x in (1-x)BaTiO3-xBi(Mg0.5Ti0.5)O3 above these values. These results show the simultaneous increase of T[&eh;r(max.)] and d33(eff.) for the films above x = 0.2 that normally showed treads off characteristics. [ABSTRACT FROM AUTHOR]

The electric field-temperature phase diagrams of three bismuth sodium titanate-based relaxor ferroelectrics are reported, namely 0.94(Na1/2Bi1/2TiO3)-0.06(BaTiO3), 0.80(Na1/2Bi1/2TiO3)-0.20(K1/2Bi1/2TiO3) and 0.75(Na1/2Bi1/2TiO3)-0.25(SrTiO3). Relaxor behavior is demonstrated by temperature-dependent dielectric permittivity measurements in the unpoled and poled states, as well as by the field-induced phase transition into a ferroelectric phase from the relaxor phase. From temperature-dependent thermometry measurements, we identified the threshold electric field to induce the ferroelectric phase and obtained the released latent heat of the phase transition. We determined the nonergodic and ergodic relaxor phase temperature range based on the absence or presence of reversibility of the relaxor to ferroelectric transition. For all three compositions, the electric field-temperature phase diagram was constructed and a critical point was identified. The constructed electric field-temperature phase diagrams are useful to find optimum operational ranges of ferroelectrics and relaxors for electromechanical and electrocaloric applications. [ABSTRACT FROM AUTHOR]

Understanding the dynamic behavior of interfaces in ferroic materials is an important field of research with widespread practical implications, as the motion of domain walls and phase boundaries are associated with substantial increases in dielectric and piezoelectric effects. Although commonly studied in the macroscopic regime, the local dynamics of interfaces have received less attention, with most studies limited to domain growth and/or reversal by piezoresponse force microscopy (PFM). Here, spatial mapping of local domain wall‐related relaxation in a tensile‐strained PbTiO3 thin film using time‐resolved band‐excitation PFM is demonstrated, which allows exploring of the field‐induced strain (piezoresponse) as a function of applied voltage and time. Through multivariate statistical analysis on the resultant 4‐dimensional dataset (x,y,V,t) with functional fitting, it is determined that the relaxation is strongly correleated with the distance to the domain walls, and varies based on the type of domain wall present in the probed volume. Phase‐field modeling shows the relaxation behavior near and away from the interfaces, and confirms the modulation of the z‐component of polarization by wall motion, yielding the observed piezoresponse relaxation. These studies shed light on the local dynamics of interfaces in ferroelectric thin films, and are therefore important for the design of ferroelectric‐based components in microelectromechanical systems. [ABSTRACT FROM AUTHOR]

Giant electromechanical response viaferroelastic domain switching is achieved in epitaxial (001) ferroelectric tetragonal (T) PbZr0.3Ti0.7O3/rhombohedral (R) PbZr0.55Ti0.45O3 bilayers, grown on La0.67Sr0.33MnO3 buffered SrTiO3 substrates. X-ray diffraction and transmission electron microscopy show that the domain structure of the T films is tuned as a function of its thickness, from a fully a1/a2-domains (30 nm thick T layer) to a three domain stress-free c/a1/c/a2 polytwin state (100 nm thick T layer). A large switchable polarization is found up to 65 μC cm−2. Quantitative piezoelectric force microscopy reveals enhanced piezoelectric coefficients, with d33 coefficients ranging from 250 to 350 pm V−1, which is up to seven times higher than the nominal PbZrxTi1−xO3 thin film values. These are attributed to the motion of nanoscale ferroelastic domains. Fatigue testing proves that these domains are reversible and repeatable up to 107 cycles. In-situ X-ray synchrotron measurements reveal that the ferroelastic domain switching is promoted by a pulsating strain effect imposed by the R layer. The study reports a fundamental understanding of the origin of giant piezoelectric coefficients in epitaxial ferroelectric bilayers. [ABSTRACT FROM AUTHOR]

Changes in crystal structure and ferroelectric properties are investigated for (100)/(001)-oriented epitaxial PbTiO3 thin films grown on CaF2 substrates by metal organic chemical vapor deposition. In this work, PbTiO3 films, with thickness ranging from 60 to 2000 nm, presented volume fraction of (001)-oriented c-domain higher than 90%. Hence, the residual strain is smaller compared to films deposited on widely investigated SrTiO3 substrates. Additionally, more than 60 μC/cm2 remnant polarization is obtained for all film thickness ranges, and the estimated spontaneous polarization taking into account c-domain volume fraction is about 80 μC/cm2 regardless of film thickness, in good agreement with reported values for the single crystal. [ABSTRACT FROM AUTHOR]

The nonlinear response of a ferroic to an applied field has been studied through the phenomenological Rayleigh Law for over a hundred years. Yet, despite this, the fundamental physical mechanisms at the nanoscale that lead to macroscopic Rayleigh behavior have remained largely elusive, and experimental evidence at small length scales is limited. Here, it is shown using a combination of scanning probe techniques and phase field modeling, that nanoscale piezoelectric response in prototypical Pb(Zr,Ti)O3 films appears to follow a distinctly non-Rayleigh regime. Through statistical analysis, it is found that an averaging of local responses can lead directly to Rayleigh-like behavior of the strain on a macroscale. Phase-field modeling confirms the twist of the ferroelastic interface is key in enhancing piezoelectric response. The studies shed light on the nanoscale origins of nonlinear behavior in disordered ferroics. [ABSTRACT FROM AUTHOR]

Raman scattering spectra and ferroelectric properties of epitaxial tetragonal Pb(Zr, Ti)O3 were investigated for polar axis-oriented thin films with various Zr/(Zr + Ti) ratios and by changing the ratios from 0 to 0.50 at different measurement temperatures. The chosen films in the thickness range of 1–2 μm present the advantage of showing small residual strain. The E (TO) modes were successfully isolated using cross-polarization configurations, while A1 (TO) and B1 modes were activated using parallel polarization configurations. Systematic changes in Raman peak positions were observed with changes in the Zr/(Zr + Ti) ratios at different measurement temperatures. It was found in both cases that the tetragonal distortion (c/a-1) and the value of square of spontaneous polarization (Ps2) linearly increased with increasing ω2[A1(1TO)], where a and c are the lattice parameters of a and c-axes. This indicates that monitoring A1(1TO) mode is efficient as a characterization method of ferroelectricity. It can also be used as a novel nondestructive process check or reliability assessment technique during fabrication of microelectromechanical systems (MEMS) using piezoelectric materials. [ABSTRACT FROM PUBLISHER]

The structural and ferroelectric domain variants of highly strained BiFeO3 films grown on vicinal LaSrAlO4 substrates were studied by piezoelectric force microscopy and high-resolution x-ray reciprocal space mapping. Through symmetry breaking of the substrate surface, ferroelastic domain variants in the highly strained MC phase BiFeO3 can be greatly reduced in thinner, purely tetragonal-like films. More interestingly, in thicker, mixed phase films, the structural variants can also be tailored by substrate vicinality. These findings lead to better understanding of the phase evolution and polarization rotation process in the strain-driven polymorphic phase system. [ABSTRACT FROM AUTHOR]

We have studied the strain field around the 90° domains and misfit dislocations in PbTiO3/SrTiO3 (001) epitaxial thin films, at the nanoscale, using the geometric phase analysis (GPA) combined with high-resolution transmission electron microscopy (HRTEM) and high-angle annular dark field--scanning transmission electron microscopy (HAADF-STEM). The films typically contain a combination of a/c-mixed domains and misfit dislocations. The PbTiO3 layer was composed from the two types of the a-domain (90 domain): a typical a/c-mixed domain configuration where a-domains are 20-30 nm wide and nano sized domains with a width of about 3 nm. In the latter case, the nano sized a-domain does not contact the film/substrate interface; it remains far from the interface and stems from the misfit dislocation. Strain maps obtained from the GPA of HRTEM images show the elastic interaction between the a-domain and the dislocations. The normal strain field and lattice rotation match each other between them. Strain maps reveal that the a-domain nucleation takes place at the misfit dislocation. The lattice rotation around the misfit dislocation triggers the nucleation of the a-domain; the normal strains around the misfit dislocation relax the residual strain in a-domain; then, the a-domain growth takes place, accompanying the introduction of the additional dislocation perpendicular to the misfit dislocation and the dissociation of the dislocations into two pairs of partial dislocations with an APB, which is the bottom boundary of the a-domain. The novel mechanism of the nucleation and growth of 90° domain in PbTiO3/SrTiO3 epitaxial system has been proposed based on above the results. [ABSTRACT FROM AUTHOR]

The ferroelectric domain structure of a PbTiO3 thin film on (100) SrTiO3 has been investigated by transmission electron microscopy (TEM). Two types of a-domain were found: one extended through the film to the surface and another comprised small a-domains confined within the film. Dark-field TEM (DFTEM) observation revealed that 180° domains formed near the substrate and stopped their growth 100 nm away from the substrate. The DFTEM observation also revealed that 90° domain boundaries had head-to-tail structures. To confirm the polarization direction obtained by experiments, diffracted intensities under a two-beam condition were simulated using the extended Darwin-Howie-Whelan equations. On the basis of the obtained results, a ferroelectric domain structure model of PbTiO3 thin films on SrTiO3 is proposed. [ABSTRACT FROM AUTHOR]

The ferroelectric property, crystal structure, and A1(1TO) soft mode of almost strain-free epitaxial polar axis-oriented tetragonal lead zirconate titanate thick films grown on CaF2 substrates were investigated by changing the Zr/(Zr+Ti) ratio and the temperature. The square of spontaneous polarization (Ps), Ps2, monotonically increased as tetragonal distortion, (c/a)-1, increased where a and c are the lattice parameters of the films and as the square of frequency in A1(1TO), ω2[A1(1TO)], increased. Additionally, the relationships of Ps2, (c/a-1), and ω2[A1(1TO)] were experimentally obtained, which confirmed the Ps value obtained from (c/a-1) and ω[A1(1TO)] without direct polarization measurements. [ABSTRACT FROM AUTHOR]

We employed in situ Raman spectroscopy under electric field for (100)/(001)-oriented tetragonal Pb(Ti0.61Zr0.39)O3 films with (001)-volume fraction (VC) of 35%. The increase in VC was revealed above 200 kV/cm, which resulted in the larger remanent polarization. In addition, the application of high enough field also brings a feature, i.e., large reversible change in VC with/without electric field that can quantitatively explain the enhanced piezoelectric response. These demonstrate the usefulness of in situ Raman observation to probe the domain contributions to the electrical and piezoelectric responses. [ABSTRACT FROM AUTHOR]

We investigated the polarized Raman spectra of a strain-free, unipolar-axis oriented tetragonal Pb(Zr,Ti)O3 thick epitaxial film. We evaluated the single crystal-like selection rules of the A1- and E-symmetry components, and found an anomalous behavior in the angular dependence of the A1(1TO)-mode intensity similar to that observed in high-Tc superconductor single crystals. Raman tensor analyses of the A1(1TO) mode revealed complex phases may exist between two independent Raman-tensor components even in the single 180° domain state. [ABSTRACT FROM AUTHOR]

Perfectly oriented (001), (101), and (111) Pb(Zr0.35Ti0.65)O3 (PZT) films were grown on identical (111)CaF2 substrates by metal-organic chemical vapor deposition. These films exclude domains parallel to the surface; therefore, all domains are actively switchable under the electric field between top and bottom electrodes. Saturation polarization values, Psat(001), Psat(101), and Psat(111), for these PZT films were 75, 50, and 43 μC/cm2, respectively. This orientation dependency was in a good agreement with the theoretical relationship for a tetragonal PZT single crystal, where Psat(001)=Psat(101)/2=Psat(111)/3. [ABSTRACT FROM AUTHOR]

An amendment to this paper has been published and can be accessed via a link at the top of the paper. [ABSTRACT FROM AUTHOR]

Ferroelectric properties were investigated for (100), (110), and (111)-single-oriented rhombohedral Pb(Zr0.65Ti0.35)O3 films. Saturation polarization, Psat, was changed by the simple tilting angle of the polar axis from the film surface normal. On the other hand, (100)- and -oriented films prepared on (100) Si substrates showed similar Psat values due to the coexistence of orientation. The coercive field, Ec, of rhombohedral Pb(Zr0.65Ti0.35)O3 films was lower than that of tetragonal Pb(Zr0.4Ti0.6)O3 films. (100)-oriented rhombohedral films with SrRuO3 electrodes did not show noticeable degradation in polarization up to 1010 switching cycles. These results show that (100)-oriented rhombohedral Pb(ZrxTi1−x)O3 film is available to realize the low voltage operated ferroelectric random access memory instead of the present tetragonal Pb(ZrxTi1−x)O3 films. [ABSTRACT FROM AUTHOR]

100-oriented epitaxial Pb(Zr,Ti)O3 [PZT] films with various Zr/(Zr+Ti) ratios from 0 to 0.8 were grown on (100)c SrRuO3∥(100) SrTiO3 and (100)c SrRuO3∥(100) LaNiO3∥(001) CaF2 substrates. 200-nm-thick films grown on CaF2 substrates consisted of a pure tetragonal phase up to the Zr/(Zr+Ti) ratio of 0.8. On the other hand, the phase of the films on SrTiO3 substrates changed from pure tetragonal below the Zr/(Zr+Ti) ratio of 0.4 to rhombohedral above the Zr/(Zr+Ti) ratio of 0.6 through their mixture phase within the Zr/(Zr+Ti) ratio range from 0.4 to 0.6. The larger polarization value was observed to be lager for PZT films on CaF2 substrates than for PZT films on SrTiO3 substrates for all Zr/(Zr+Ti) ratios and was in good agreement with the estimated one assuming tetragonal symmetry. The tetragonal region can be expanded to a Zr/(Zr+Ti) ratio of 0.8 below 1 µm in thickness for films on CaF2 substrates. The present results show that the large thermal strain induced by CaF2 substrates having with a large thermal expansion coefficient can expand the tetragonal symmetry region up to large a Zr/(Zr+Ti) ratio and thicker films. [ABSTRACT FROM AUTHOR]

Squareness in polarization–electric field hysteresis loops of (100)-oriented epitaxial and fiber-textured rhombohedral Pb(Zr,Ti)O3 films prepared on (100) SrTiO3 and (100) Si substrates, respectively, was investigated as a function of temperature. The ratio of remanent polarization to saturation polarization (Pr/Psat) decreased with increasing temperature for all films. It depends on the kind of substrates and the remained strain in the in-plane orientation. These data suggest that the existing strain in the films possibly affects the temperature dependence of the Pr/Psat ratio. [ABSTRACT FROM AUTHOR]

Films of a high-pressure perovskite phase, Bi(Mg1/2Ti1/2)O3, were prepared on (111)c-oriented SuRuO3-coated (111)Pt/TiO2/SiO2/(100)Si substrates. The perovskite Bi(Mg1/2Ti1/2)O3 films had a (111) one-axis orientation, because their constituent grains were epitaxially grown on (111)c-oriented perovskite SrRuO3 ones. The remanent polarization and piezoelectric constant measured at an applied electric field of 600 kV/cm were about 30 µC/cm2 and 40 pm/V, respectively. A remarkable phase transition was not observed from room temperature to 350 °C in a (111) one-axis-oriented Bi(Mg1/2Ti1/2)O3 film, suggesting that the Curie temperature of this film is above 350 °C. [ABSTRACT FROM AUTHOR]

100-oriented epitaxial Pb(Zr0.65Ti0.35)O3 films with various film thicknesses from 0.1 to 3 µm were grown on (100)cSrRuO3 ∥ (100)SrTiO3 and (100)cSrRuO3 ∥ (100)LaNiO3 ∥ (001)CaF2 substrates. The out-of-plane/in-plane lattice parameter ratio of the films on the CaF2 substrates was larger than that on the SrTiO3 substrates up to 1.1 µm film thickness, while (90°-α) (α was defined as the internal tilt angle) was almost 0°. Results of analysis of Raman spectra and piezoresponse images suggest that the 1.1-µm-thick film grown on the (100)cSrRuO3 ∥ (100)LaNiO3 ∥ (001)CaF2 substrate had tetragonal symmetry with a polar-axis orientation. Moreover, the saturation polarization values of the films measured from P–E hysteresis loops correspond to the two Ps values estimated from the thermodynamic theory, assuming the change in the polar direction due to the symmetry change to tetragonal, and from the crystal distortion in tetragonal symmetry. This can be explained by the large compressive stress from the CaF2 substrate having a large thermal expansion coefficient. [ABSTRACT FROM AUTHOR]

The origin of the ferroelectricity of Bi(Mg1/2Ti1/2)O3 films was investigated. Epitaxial Bi(Mg1/2Ti1/2)O3 films with film thicknesses of 50 to 800 nm were grown on (111)cSrRuO3/(111)SrTiO3 substrates by pulsed laser deposition. A Bi(Mg1/2Ti1/2)O3 film was not strongly clamped from the substrate and identified to have rhombohedral symmetry with a = 0.398 nm and α= 89.8°, which was independent of film thickness within 100 to 800 nm. The relative dielectric constant, remanent polarization, and coercive field of the Bi(Mg1/2Ti1/2)O3 films at room temperature were almost constant at about 250, 60 µC/cm2, and 240 kV/cm, respectively, for film thicknesses above 200 nm. These data suggest that Bi(Mg1/2Ti1/2)O3 films are ferroelectric. [ABSTRACT FROM AUTHOR]

A correction to the article "Spontaneous polarization estimation from the soft mode in strain-free epitaxial polar axis-oriented Pb(Zr,Ti)O3 thick films with tetragonal symmetry," that was published in the 2011 issue is presented.

Thin films of SrBi4Ti4O15, a kind of bismuth layer-structured dielectrics (BLSDs), were prepared on platinized silicon wafers buffered by perovskite-type oxide interface layers, (100)LaNiO3/(111)Pt/TiO2/(100)Si and (001)Ca2Nb3O10-nanosheets/(111)Pt/TiO2/(100)Si, by chemical solution deposition (CSD). The Ca2Nb3O10 nanosheets were supported on a (111)Pt/TiO2/(100)Si substrate by dip coating using an aqueous dispersion, while (100)LaNiO3 was prepared by CSD. The (00l) planes of BLSD crystal were preferentially oriented on the surface of both substrates, which is caused by suitable lattice matching between the a-(b-)axis of BLSD and perovskite-type oxide layers. The film deposition on (001)Ca2Nb3O10 nanosheets yielded (001)-oriented BLSD films with higher crystallinity and smaller fluctuation in the tilting angle of the (001)BLSD plane than those on the (100)LaNiO3 interface layer. The dielectric constant (εr) of (001)-oriented SrBi4Ti4O15 film on (001)Ca2Nb3O10-nanosheets/(111)Pt/TiO2/(100)Si substrate was approximately 190, which was significantly stable against the change of frequency and bias voltage compared with that of the randomly-oriented SrBi4Ti4O15 film. [ABSTRACT FROM AUTHOR]

The structural property and electric field response of a single perovskite PbTiO3 nanowire were investigated by means of synchrotron X-ray diffraction (XRD) with a micro X-ray beam. XRD θ–2θ patterns and Raman spectra confirmed the formation of the perovskite phase of PbTiO3 by annealing the PX-phase of Pb–Ti–O nanowires at 600 °C. In addition, the obtained nanowires showed multi-domain/grain features. By focusing the micro X-ray beam on a single perovskite PbTiO3 nanowire, both ends of which are connected to electrodes, the lattice distortion under the electric field was observed. [ABSTRACT FROM AUTHOR]