The screening efficiency of a metal-ferroelectric interface plays a critical role in determining the polarization stability and hence the functional properties of ferroelectric thin films. Imperfect screening leads to strong depolarization fields that reduce the spontaneous polarization or drive the formation of ferroelectric domains. We demonstrate that by modifying the screening at the metal-...

(K(x),Na(1-x))NbO(3) (KNN) thin films were deposited on (001)SrRuO(3)/(001)Pt/(001)MgO substrates by RF-magnetron sputtering, and their piezoelectric properties were investigated. The x-ray diffraction measurements indicated that the KNN thin films were epitaxially grown with the c-axis orientation in the perovskite tetragonal system. The lattice constant of the c-axis increased with increasing...

We deposited transparent ferroelectric lead zirconate titanate thin films on fused silica and contacted them via Al-doped zinc oxide (AZO) transparent electrodes with an interdigitated electrode (IDE) design. These layers, together with a TiO2 buffer layer on the fused silica substrate, are highly transparent (>60% in the visible optical range). Fully crystallized Pb(Zr0.52Ti0.48)O3 (PZT) films...

We explore BiFeO3 under tensile strain using first-principles calculations. We find that the actual structures are more complex than what had been previously thought, and that there is a strong shear deformation type structural instability which modifies the properties. Specifically, we find that normal tensile strain leads to structural instabilities with a large induced shear deformation in (...

Raman spectra have been investigated in PbTiO 3 thin films grown on Si by metalorganic chemical vapor deposition. A large grazing-angle scattering technique was taken to measure the temperature dependence of Raman spectra below room temperature. All Raman modes in the thin films are assigned and compared with those in the bulk single crystal, a new A 1 (TO) soft mode at 104 cm~1 was recorded wh...

Interfacial strain gradients in oxide epitaxial thin films provide an interesting opportunity to study flexoelectric effects and their potential applications. Oxide epitaxial thin films can exhibit giant and tunable flexoelectric effects, which are six or seven orders of magnitude larger than those in conventional bulk solids. The strain gradient in an oxide epitaxial thin film can generate an ...

The boundary conditions, customarily used in the Landau-type approach to ferroelectric thin films and nanostructures, have to be modified to take into account that a surface of a ferroelectric is a defect of a field type. The surface (interface) field is coupled to a normal component of polarization and, as a result, the second order phase transitions are generally suppressed and anomalies in r...

Epitaxial strain can substantially enhance the spontaneous polarizations and Curie temperatures of ferroelectric thin films compared to the corresponding bulk materials. In this Letter we use first principles calculations to calculate the effect of epitaxial strain on the spontaneous polarization of the ferroelectrics , , and , and the multiferroic material . We show that the epitaxial strain d...