Oxygen Vacancies in Perovskite Oxide Piezoelectrics.

The excellent electro-mechanical properties of perovskite oxide ferroelectrics make these materials major piezoelectrics. Oxygen vacancies are believed to easily form, migrate, and strongly affect ferroelectric behavior and, consequently, the piezoelectric performance of these materials and devices based thereon. Mobile oxygen vacancies were proposed to explain high-temperature chemical reactions half a century ago.

PLD prepared bioactive BaTiO films on TiNb implants.

BaTiO (BTO) layers were deposited by pulsed laser deposition (PLD) on TiNb, Pt/TiNb, Si (100), and fused silica substrates using various deposition conditions. Polycrystalline BTO with sizes of crystallites in the range from 90nm to 160nm was obtained at elevated substrate temperatures of (600°C-700°C). With increasing deposition temperature above 700°C the formation of unwanted rutile phase prevented the growth of perovskite ferroelectric BTO.

Concurrent bandgap narrowing and polarization enhancement in epitaxial ferroelectric nanofilms.

Perovskite-type ferroelectric (FE) crystals are wide bandgap materials with technologically valuable optical and photoelectric properties. Here, versatile engineering of electronic transitions is demonstrated in FE nanofilms of KTaO, KNbO (KNO), and NaNbO (NNO) with a thickness of 10-30 unit cells. Control of the bandgap is achieved using heteroepitaxial growth of new structural phases on SrTiO (001) substrates.

Ambience-sensitive optical refraction in ferroelectric nanofilms of NaNbO.

Optical index of refraction is studied by spectroscopic ellipsometry in epitaxial nanofilms of NaNbO with thickness ∼10 nm grown on different single-crystal substrates. The index in the transparency spectral range ( ≈ 2.1 - 2.

The structure of strained perovskite KTaO(3) thin films prepared by pulsed laser deposition.

Epitaxial perovskite potassium tantalate (KTaO(3)) films with thicknesses of 7.4-36 nm are grown on SrTiO(3)(001) substrates by pulsed laser deposition. X-ray diffraction (XRD) analysis reveals evolution of lattice strain with increasing film thickness.