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The morphotropic phase boundary (MPB) region of the BFO-BTO solid solution is studied by comprehensive macroscopic and local methods, focusing on the synthesis conditions that influence the final phase composition and functional response. The difference between the phase distribution and local switching behavior in two sets of the BFO-BTO solid solutions prepared with different applied pressures is revealed and attributed to the local chemical inhomogeneity forming due to certain differences in the solid-state sintering reactions. More homogeneous mixing of the polar and non-polar phases stimulates the non-polar-to-polar phase transition and widening the MPB region. [ABSTRACT FROM AUTHOR]

In this work, the influence of the material of the contact sublayer and the growth temperature on the geometric dimensions and the value of the piezoelectric response of carbon nanotubes for their use in nanopiezotronic devices is investigated. The thermodynamic laws that characterize the processes occurring in the "catalyst/sublayer/substrate" system have been established. It was found that with an increase in temperature, the carbon nanotubes density decreases from 1.1 to 0.001 µm−2 for Mo, and from 26 to 0.1 µm−2 for Cr. The value of the piezoelectric response was estimated, which ranged from 8 to 14 nA for the Cr sublayer and from 3 to 23 nA for the Mo sublayer. It is shown that the obtained structures are promising for the creation of nanopiezotronic elements (nanogenerators, energy nanoharvesters). [ABSTRACT FROM AUTHOR]

We report on the correlated investigation between piezoelectric properties and crystalline structure of PbZr0.52Ti0.48O3 (PZT) films under different oxygen pressures in the process of pulsed laser deposition. A sharp increase of effective longitudinal-piezoelectric coefficient (305 pm/V) and especially, a high effective transverse-piezoelectric coefficient (−16.2 C/cm2) were achieved in the PZT film deposited at 0.10 mbar, where the preferred (100)-orientation and columnar-grains with an obelisk-shape microstructure were presented. The comparative discussions in this study provide valuable insights into the crystalline and microstructure contributions to improve the piezoelectric responses for wide applications in high-performance piezoelectric devices from capacitors to MEMS devices. [ABSTRACT FROM AUTHOR]

Application of electrodes from metals with different coefficients of linear thermal expansion on the opposite surfaces of non-poled plates of ferroelectric PZT-19 ceramics leads to formation of stationary gradients of mechanical strain and stresses in the samples. As a result, electric response to three-point mechanical loading, pyroelectric and piezoelectric responses, asymmetry of the polarization hysteresis loop (internal electric field), as well as the nonuniform distribution of the surface potential in the interelectrode space were observed. Unipolarity did not destroy after multiple heating and cooling cycles up to 400°C, i.e. well above the Curie temperature. [ABSTRACT FROM AUTHOR]

The piezoelectric response (PR) images of unpolarized piezoceramics PCR-1 were obtained under weak effect of the probe on the surface. The frequency dependence of PR amplitude in the range of 4–50 kHz was measured. PR creates stripes, which amplitude and size vary smoothly with frequency. The main maximum of PR amplitude (12-15 kHz) differs for crystallite and grain boundary. The decoupled approximation in the PR theory of ferroelectric-semiconductor and wave processes in a piezoelectric plate under applied alternating electric field were used to discuss a possible origin of the stripes in PR images and PR amplitude change with frequency. [ABSTRACT FROM PUBLISHER]

Piezoresponse Force Spectroscopy (PFS) has emerged as a powerful tool for probing polarization dynamics on the nanoscale. Application of a dc bias to a nanoscale probe in contact with a ferroelectric surface results in the nucleation and growth of a ferroelectric domain below the probe apex. The latter affects local electromechanical response detected by the probe. Resulting hysteresis loop contains information on local ferroelectric switching. The self-consistent analysis of the PFS data requires (a) deriving the thermodynamic parameters of domain nucleation and (b) establishing the relationships between domain parameters and PFM signal. Here, we analyze the early stages of switching processes and the effect of screening on the surface and at the domain wall on local polarization reversal mechanism. It is shown that the screening control both the domain nucleation activation energy and hysteresis loop saturation rate. [ABSTRACT FROM AUTHOR]

Data on the growth of single crystals of protein amino acids and their compounds are presented. The structure and symmetry of the crystals are discussed. The piezoelectric response was studied at temperatures between 120 K and 320 K. The results of studies of optical second harmonic generation and optical activity from the literature are presented. [ABSTRACT FROM AUTHOR]