Crystallographic, dielectric and optical properties of SrBi2Ta2O9 thin films prepared by the polymeric precursor method

Strontium bismuth tantalate thin films were prepared on several substrates (platinized silicon (PvTi/SiO2/Si), n-type (100)-oriented and p-type (111)-oriented silicon wafers, and fused silica) by the solution deposition method. The resin was obtained by the polymeric precursor method, based on the Pechini process, using strontium carbonate, bismuth oxide, and tantalum ethoxide as starting reagents. Characterizations by XRD and SEM were performed for structural and microstructural evaluations. The electrical measurements, carried on the MFM configuration, showed P-r values of 6.24 muC/cm(2) and 31.5 kV/cm for the film annealed at 800 degreesC. The film deposited onto fused silica and treated at 700 degreesC presented around 80 % of transmittance.

Characteristics of Dielectric Barrier Discharge Reactor for Material Treatment

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

Structure, microstructure and dielectric properties of 100-x(Bi0.5Na0.5)TiO3-x[SrTiO3] composites ceramics

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

Microstructure, dielectric properties and optical band gap control on the photoluminescence behavior of Ba[Zr0.25Ti0.75]O-3 thin films

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A Dielectric Model of Self-Assembled Monolayer Interfaces by Capacitive Spectroscopy

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

Dielectric relaxation and dc conductivity on the PVOH-CF(3)COONH(4) polymer system

In the present paper, the ionic conductivity and the dielectric relaxation properties on the poly(vinyl alcohol)-CF(3)COONH(4) polymer system have been investigated by means of impedance spectroscopy measurements over wide ranges of frequencies and temperatures. The electrolyte samples were prepared by solution casting technique. The temperature dependence of the sample's conductivity was modeled by Arrhenius and Vogel-Tammann-Fulcher (VTF) equations. The highest conductivity of the electrolyte of 3.41x10 (-aEuro parts per thousand 3) (Omega cm) (-aEuro parts per thousand 1) was obtained at 423 K. For these polymer system two relaxation processes are revealed in the frequency range and temperature interval of the measurements. One is the glass transition relaxation (alpha-relaxation) of the amorphous region at about 353 K and the other is the relaxation associated with the crystalline region at about 423 K. Dielectric relaxation has been studied using the complex electric modulus formalism. It has been observed that the conductivity relaxation in this polymer system is highly non-exponential. From the electric modulus formalism, it is concluded that the electrical relaxation mechanism is independent of temperature for the two relaxation processes, but is dependent on composition.

Structural refinement, optical and microwave dielectric properties of BaZrO3

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

Optical and dielectric relaxor behaviour of Ba(Zr0.25Ti0.75)O-3 ceramic explained by means of distorted clusters

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Structural and dielectric properties of Ba0.5Sr0.5(SnxTi1-x)O-3 ceramics obtained by the soft chemical method

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Structural and dielectric relaxor properties of yttrium-doped Ba(Zr0.25Ti0.75)O-3 ceramics

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Dielectric properties of pure and lanthanum modified bismuth titanate thin films

We investigated the dielectric properties of pure and lanthanum modified bismuth titanate thin films obtained by the polymeric precursor method. X-ray diffraction of the film annealed at 300 degrees C for 2h indicates a disordered structure. Lanthanum addition increases gradually the dielectric permittivity of films, keeping unchanged their loss tangent. From C-V curve we can see no hysteresis behavior indicating the absence of domain structure. The decrease in the conductivity for the heavily doped Bi4Ti3O12 (BIT) must be associated to the unidentified crystal defects. For comparison, dielectric properties of crystalline BIT film were also investigated. (C) 2007 Published by Elsevier B.V.

The dielectric suppress and the control of semiconductor non-Ohmic feature of CaCu3Ti4O12 by means of tin doping

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Dielectric properties of soft chemical method derived CaCu3Ti4O12 thin films onto Pt/TiO2/Si(100) substrates

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Structural, dielectric and ferroelectric properties of Nb-doped PZT thin films produced by oxide precursor method

Recently, was proposed a chemical method for preparation of ferroelectric thin films based on oxide precursors. In this work, PZT thin films were prepared to attest the viability of this method for cation-substitution. In this study, a small concentration of Nb (5 mol%) was selected as substitute of B-site in ABO 3 structure of PZT. Dielectric and ferroelectric properties of PZT films were studied as a function of cation-substitution. Results for Nb-PZT were compared with PZT films undoped. The values of dielectric constant, at typical 100 kHz frequency, were 358 and 137, for PZT and Nb-PZT films respectively. Remanent polarizations of these films were respectively 7.33 μ C/cm 2 and 13.3 μ C/cm 2 , while the measured coercive fields were 101 kV/cm and 93 kV/cm. As a result, changes on observed dielectric and ferroelectric values confirm the Nb substitution in PZT thin film produced by oxide precursor method. © 2002 Taylor & Francis.

Crystallographic, dielectric and optical properties of SrBi 2Ta2O9 thin films prepared by the polymeric precursor method

Strontium bismuth tantalate thin films were prepared on several substrates (platinized silicon (Pt/Ti/SiO 2 /Si), n -type (100)-oriented and p -type (111)-oriented silicon wafers, and fused silica) by the solution deposition method. The resin was obtained by the polymeric precursor method, based on the Pechini process, using strontium carbonate, bismuth oxide, and tantalum ethoxide as starting reagents. Characterizations by XRD and SEM were performed for structural and microstructural evaluations. The electrical measurements, carried on the MFM configuration, showed P r values of 6.24 μC/cm 2 and 31.5 kV/cm for the film annealed at 800 C. The film deposited onto fused silica and treated at 700 C presented around 80% of transmittance. © 2002 Taylor & Francis.