Publications de Nava Setter | EPFL Graph Search

Chattez avec Graph Search

Posez n’importe quelle question sur les cours, conférences, exercices, recherches, actualités, etc. de l’EPFL ou essayez les exemples de questions ci-dessous.

AVERTISSEMENT : Le chatbot Graph n'est pas programmé pour fournir des réponses explicites ou catégoriques à vos questions. Il transforme plutôt vos questions en demandes API qui sont distribuées aux différents services informatiques officiellement administrés par l'EPFL. Son but est uniquement de collecter et de recommander des références pertinentes à des contenus que vous pouvez explorer pour vous aider à répondre à vos questions.

For the first time we have characterized a micromotor driven by a piezoelectric PZT (PbZrxTi1-xO3) thin film. Sputter and sol-gel techniques have been applied for the deposition of the PZT films onto a silicon stator membrane, which is 20-30 mu m thick and has a diameter of 4 mm. The amplitudes of the membrane deflections are measured by means of laser interferometry. They are as large as 800 nm V-1 at the first resonance (26 kHz) and 60 nm V-1 at 1 kHz. This is one order of magnitude larger than previously

Coupling between electrical and mechanical phenomena is ubiquitous in nature and underpins the functionality of materials and systems as diversified as ferroelectrics and multiferroics to electroactive molecules to biological systems. Recent years have wit ...

A simple and reliable method which allows one to distinguish between the two major microscopic scenarios for the suppression of the switching polarization (P-r(s)), i.e., pinning of ferroelectric domain walls (DWs) through the Pb(Zr,Ti)O-3 film (PZT) (bulk scenario) and inhibition of the growth of opposite domains due to the nucleus suppression at the electrode interfaces (interface scenario), is proposed. In addition, a new electric treatment able to significantly suppress P-r(s) in Pt-PZT-Pt ferroelectric

Weak field piezoelectric coefficient and strain were investigated in ferroelectric SrBi2Ta2O9 (SET) thin films by means of optical interferometry. Though the maximum polarization and dielectric constant were small enough (7 mu C/cm(2) and 150, respectively), the piezoelectric coefficient attained 17 pm/V under the de electric field. This value is comparable with the piezoelectric coefficients reported previously on poled SET ceramics, Electrically induced strain of 5.10(-4) was observed using bipolar drivin

Research and development in the field of electroceramics is driven by technology and device applications. It includes research on a broad spectrum of inorganic materials, and it covers all scales from the level of the crystalline lattice to that of final devices. The applications find a place in an increasing number of domains, ranging from environment monitoring and transportation, through medicine and health-care, to electronics and communications. Two tendencies are emerging: surface and interface phenom

Properties of ferroelectric domain walls are attractive for future nano- and optoelectronics. An important element is the potential to electrically erase/rewrite domain walls inside working devices. Dense domain wall patterns, formed upon cooling through t ...

A theoretical study on the effect of spontaneous polarization screening on the dielectric response of ferroelectric films with 180 degrees domains going through the film thickness (through-domains) is presented. It has been shown by several researchers tha ...

Sol-gel deposited Pb(Ti,Zr)O-3 thin films have been used to integrate pyroelectric arrays on silicon. The arrays of 1x12 (element size of 600 x 1100 mm(2)) and 1x50 elements (element size of 140 x 1100 mm(2)) are fabricated by standard photolithography techniques on top of a SiO2/Si3N4 buffer layer which acts as a thermally insulating membrane after micromachining of the silicon. The devices have been characterized using a large aperture blackbody radiation source operating at 423 K. Its radiation is focuss

PbTiO3 thin films were prepared from alkoxide solution precursors and crystallized onto Pt/TiO2/SiO2/Si substrates. Microscopy observations revealed that the complexity of the domain walls structure decreased with the grain size. Dielectric, electrostrictive, and piezoelectric properties of the films were characterized in details. A shift of the temperature of the dielectric permittivity maximum due to stresses in the plane of films has been observed. Electrostrictive M and Q coefficients were estimated by

The results of structural and electrical characterizations of SrTiO3 thin films deposited onto MgO and LaAlO3 substrates by pulsed laser deposition technique are presented. The influence of substrate and annealing procedure on the crystalline structure and dielectric properties of these ferroelectric thin films are investigated. The obtained experimental data are analyzed in terms of the Landau theory taking into account the room-temperature lattice mismatch of the ferroelectric and substrates as well as th

The orientation dependence of the longitudinal piezoelectric coefficient, d(33)(), is investigated as a function of temperature in BaTiO3 and PbTiO3 crystals using the Landau-Ginsburg-Devonshire theory. We show that a presence of the ferroelectric-ferroelectric phase transitions in BaTiO3 leads to enhanced d(33)() along nonpolar directions. The reason for this is that in the vicinity of a phase transition temperature at which a polarization vector changes its direction (tetragonal-orthorhombic/monoclinic,

The stabilities of Pt/Ti bilayer metallizations in an oxidizing atmosphere have been investigated with several thicknesses of interfacial Ti-bonding layers. Reactions in the Pt/Ti/SiO2/Si interface were examined as a function of various annealing conditions in the temperature range 200-800 degrees C by using Rutherford backscattering spectrometry, Auger electron spectroscopy, x-ray diffraction, and transmission electron microscopy. Thermal treatment in oxygen was found to cause rapid oxidation of the Ti lay

Degradation of piezoelectric properties has been studied in ferroelectric PZT films by means of optical interferometry. The degradation under de bias and aging of poled films have been observed. The decay of piezoelectric coefficient with time is described by a logarithmic law with aging rates comparable to those of switching polarization. The aging rates are shown to be sensitive to poling conditions and to orientation of the poling field with respect to the direction of preferred polarization. The fatigue

The in-situ growth of PbZrxTi1-xO3 (PZT) and PbTiO3 (PT) thin films by reactive sputter deposition has been investigated for applications with silicon substrates. In-situ deposition from three simultaneously operating magnetron sources was applied. At the selected growth temperature range (550-600 degrees C), self-stabilisation of lead composition by a lar ge desorption rate of Pb on stoichiometric PZT surfaces has been observed. Interlayer mixing was found to be limited to a few monolayers. Both Pt and RuO

The properties of the cation vacancy and the Te antisite, two dominant defects in CdTe and Cd1-xZnxTe alloys grown in Te-rich conditions, are examined using first-principles calculations. First, the structure, electronic levels, and migration paths of V-Cd ...

Direct observation of polarization distribution at nanoscale by scanning force microscopy across partially etched Pb(Zr,Ti)O-3 film ferroelectric capacitors with size 2x3 mum and preferential orientation (111) has revealed an anomalous polarization pattern characterized by polarization inversion in the center of the capacitor. This self-structured pattern is reproducible and independent on the spontaneous polarization orientation, but strongly influenced by the film texture and capacitor size. In particular

The size, shape, and polarization orientation of fatigued areas formed during the suppression of the switchable polarization (P-r(s)) (fatigue) in Ft-FZT-Pt ferroelectric capacitors (FECAPs), were observed by means of atomic force microscopy and by imaging the phase of the piezoelectric vibration induced by a low ac field applied between the top and bottom electrodes. In the virgin state (FECAP as prepared), the pattern of the polarization domains with opposite orientation was randomly distributed with typi

The microstructure and preferred orientations of rapid thermally annealed Pb(Zr0.53, Ti0.47)O3 films, deposited on Pt/Ti/SiO2/Si electrode/substrates by solution-gel spinning, have been investigated using analytical and high-resolution electron microscopy and X-ray diffraction. The temperature of pyrolysis of the PZT filMS was found to influence the preferred orientation of the film: lower temperatures (350-degrees-C) favored a (111) orientation, whereas higher temperatures (420-degrees-C) favored a (100) o

Recent progress in integrating ferroelectrics directly on silicon opens the exciting possibility of implementing ferroelectric-semiconductor devices [1]. One of the major problems for such integration is the instability of the ferroelectric state in very t ...

In ferroelectric materials, domain wall displacement plays a key role in the dielectric properties measured with respect to the driving field amplitude and frequency. The low to medium field dielectric response in many ferroic systems can be often described by classical Rayleigh model, which is rate-independent i.e., it depends only on the strength of ac signal. However experiments show that the nonlinear parameters are frequency dependent. Thus a more general approach, which can describe both purely nonlin

Nava Setter

Chattez avec Graph Search

Fabrication and Characterization of Pzt Thin-Film Vibrators for Micromotors

Electromechanics on the Nanometer Scale: Emerging Phenomena, Devices, and Applications

Discrimination between bulk and interface scenarios for the suppression of the switchable polarization (fatigue) in Pb(Zr,Ti)O-3 thin films capacitors with Pt electrodes

Electromechanical properties of SrBi2Ta2O9 thin films

Electroceramics: looking ahead

Room temperature concurrent formation of ultra-dense arrays of ferroelectric domain walls

Effect of spontaneous polarization screening on dielectric response of ferroelectric polydomain films

Pyroelectric thin film sensor arrays integrated on silicon

Properties of ferroelectric PbTiO3 thin films

Shift of phase transition temperature in strontium titanate thin films

Piezoelectric anisotropy-phase transition relations in perovskite single crystals

Investigation of Pt/Ti Bilayer Metallization on Silicon for Ferroelectric Thin-Film Integration

Interferometric study of piezoelectric degradation in ferroelectric thin films

In-situ sputter deposition of PT and PZT films on platinum and RuO2 electrodes

Cation-site intrinsic defects in Zn-doped CdTe

Unusual size effect on the polarization patterns in micron-size Pb(Zr,Ti)O-3 film capacitors

Direct observation of region by region suppression of the switchable polarization (fatigue) in Pb(Zr,Ti)O-3 thin film capacitors with Pt electrodes

Use of Transmission Electron-Microscopy for the Characterization of Rapid Thermally Annealed, Solution-Gel, Lead-Zirconate-Titanate Films

Control of the Screening Ability at a Ferroelectric-Semiconductor Interface

Analysis of the non linear domain wall response in ferroelectric thin films