We demonstrate that the frozen-ion contribution to the flexoelectric coefficient is given solely in terms of the sum of third moments of the charge-density distortions induced by atomic displacements, even for ferroelectric or piezoelectric materials. We introduce several practical supercell-based methods for calculating these coefficients from first principles, and demonstrate them by computin...

We report studies of ferroelectricity in ultra-thin perovskite films with realistic electrodes. The results reveal stable ferroelectric states in thin films less than 10 Å thick with polarization normal to the surface. Under short-circuit boundary conditions, the screening effect of realistic electrodes and the influence of real metal/oxide interfaces on thin film polarization are investigated....

[011]-oriented unpoled relaxor ferroelectric Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 crystals are studied by means of acoustic emission and dielectric methods in dependence on both temperature dc bias electric field. The rhombohedral-cubic phase transition the maximum as well intermediate successfully detected. Both field, too. No critical end point, but tricritical one is Existence supercriti...

Ferroelectric PbTiO3 nanostructures have been fabricated using two different procedures that involve microemulsions and Chemical Solution Deposition onto Pt/TiO2/SiO2/(100)Si substrates. The first procedure enables the fabrication of structures with controlled size and shape, as observed by Atomic Force Microscopy (AFM) topography and computer assisted quantitative analysis, while the second pr...

Using in situ high-resolution synchrotron x-ray scattering, the Curie temperature TC has been determined for ultrathin c-axis epitaxial PbTiO3 films on conducting substrates (SrRuO3 on SrTiO3), with surfaces exposed to a controlled vapor environment. The suppression of TC was relatively small, even for the thinnest film (1.2 nm). We observe that 180 degrees stripe domains do not form, indicatin...

Thermal decompositions of the precursors for chemical solution deposition of 0.7 Pb(Mg1/3Nb2/3)O3-0.3 PbTiO3 thin films were studied. The precursors were prepared from lead acetate or acetylacetone-modified lead acetate by diol-based route, and dried at 100 C. Thermal decompositions of the PT, PMN and PMN-PT precursors in air occur stepwise. Between room temperature and approximately 200 C the ...

We find an unexpected tetragonal-to-monoclinic-to-rhombohedral-to-cubic phase transition sequence induced by pressure, and a morphotropic phase boundary in a pure compound using first-principles calculations. Huge dielectric and piezoelectric coupling constants occur in the transition regions, comparable to those observed in the new complex single-crystal solid-solution piezoelectrics such as P...

Using ultrasonic spectroscopy, the frequency dispersions of ultrasonic velocity and attenuation were measured for single crystal 0.72 Pb(Mg1/3Nb2/3)20.28 PbTiO3 (PMN228%PT! with engineered domain structures in the frequency range of 50–110 MHz. We found that the velocity dispersion and attenuation are very small for the longitudinal wave propagating along @001# of the pseudotetragonal state. Ou...

Thin films of PbTiO3, a classical ferroelectric, have been grown under tensile strain on single-crystal substrates of DyScO3. The films, of only 5 nm thickness, grow fully coherent with the substrate, as evidenced by synchrotron x-ray diffraction. A mapping of the reciprocal space reveals intensity modulations (satellites) due to regularly spaced polar domains in which the polarization appears ...