Influence of oxygen atmosphere on crystallization and properties of LiNbO3 thin films

Thin films of lithium niobate were deposited on the Pt/Ti/SiO2 (111) substrates by spin coating from the polymeric precursor method (Pechini process). Annealing in static air and oxygen atmosphere was performed at 500 degreesC for 3 h. The films obtained were characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The dielectric constant and dissipation factor were measured in frequency region from 10 Hz to 10 MHz. Electrical characterization of the films pointed to ferroelectricity via hysteresis loop. The influence of oxygen atmosphere on crystallization, morphology and properties of LiNbO3 thin films is discussed. (C) 2003 Elsevier Ltd. All rights reserved.

Quantum Mechanics Insight into the Microwave Nucleation of SrTiO3 Nanospheres

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Size effects of polycrystalline lanthanum modified Bi4Ti3O12 thin films

The film thickness dependence on the ferroelectric properties of lanthanum modified bismuth titanate Bi3.25La0.75Ti3O12 was investigated. Films with thicknesses ranging from 230 to 404 nut were grown on platinum-coated silicon substrates by the polymeric precursor method. The internal strain is strongly influenced by the film thickness. The morphology of the film changes as the number of layers increases indicating a thickness dependent grain size. The leakage current, remanent polarization and drive voltage were also affected by the film thickness. (c) 2007 Elsevier Ltd. All rights reserved.

Rietveld analysys and electrical properties of lanthanum doped BiFeO3 ceramics

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Lanthanum doped BiFeO3 powders: Syntheses and characterization

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Structure and ferro/piezoelectric properties of SrBi(4)Ti(4)O(15) films deposited on TiO(2) buffer layer

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Structure study of Bi4Ti3O12 produced via mechanochemically assisted synthesis

Nanosized bismuth titanate was prepared via high-energy ball milling process through mechanically assisted synthesis directly from their oxide mixture of Bi2O3 and TiO2. Only Bi4Ti3O12 phase was formed after 3 h of milling time. The excess of 3 wt% Bi2O3 added in the initial mixture before milling does not improve significantly the formation of Bi4Ti3O12 phase comparing to stoichiometric mixture. The formed phase was amorphized independently of the milling time, The Rietveld analysis was adopted to determine the crystal structure symmetry, amount of amorphous phase, crystallite size and microstrains. With increasing the milling time from 3 to 12 h, the particle size of formed Bi4Ti3O12 did not reduced significantly. That was confirmed by SEM and TEM analysis. The particle size was less than 20 nm and show strong tendency to agglomeration. The electron diffraction pattern indicates that Bi4Ti3O12 crystalline powder is embedded in an amorphous phase of bismuth titanate. Phase composition and atom ratio in BIT ceramics were determined by X-ray diffraction and EDS analysis. (c) 2007 Elsevier Ltd. All rights reserved.

Feasibility of internal standardization in the direct and simultaneous determination of As, Cu and Pb in sugar-cane spirits by graphite furnace atomic absorption spectrometry

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)