Nanostructured LaFeO

The orthorhombic LaFeO3 thin films grown by pulsed laser deposition on silicon showed nano-structuration of their surface and preferential crystallographic exposed facets, depending on the deposition temperature. The LaFeO3 film deposited at 850 °C has two types of grain termination, flat or tip-like, corresponding to two different growth directions, respectively [110] and [200]. However, due to the shape of the termination, the two types of grains expose the same {110} facets. The prepared lanthanum iron oxide films are iron deficient and consequently contains oxygen vacancies, the exact chemical formula being LaFe0.82O3-δ

Phase Separation in an SiCO Glass Studied by Transmission Electron Microscopy and Electron Energy-Loss Spectroscopy

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Investigation of SiCO glasses synthesized with extensive ball milling

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Radiation effects on switching kinetics of three-dimensional ferroelectric capacitor arrays

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Investigation of Elastic Properties of WO3 Thin Films Supported on Quartz in Surface Acoustic Wave Sensing Devices

International audienceThis study aims to discuss the combined theoretical and experimental results of elastic properties of tungsten trioxide films supported on Quartz (YX)/45°/10° resonator to form surface acoustic wave (SAW) devices. The SAW systems with different thicknesses of WO3 thin films were imaged and structurally characterized by X-ray diffraction, atomic force, and transmission electron microscopy. The deposited WO3 films (100, 200, and 300 nm of thickness) crystallized in a single monoclinic phase. The acoustoelectric properties of the SAW system were obtained by combining theoretical simulations with experimental measurements. The modeling of the SAW devices has been performed by the finite element and boundary element methods (FEM/BEM). The elastic constants of the films at room temperature were assessed via electrical admittances experiments in light of theoretical calculations. The gravimetric effect of the deposited layers is observed by a shift of the resonance frequency to lower values as the thickness of the films increases. Moreover, the acoustic losses are affected by the dielectric losses of the WO3 films while the resonant frequency decreases almost linearly. SAW devices revealed strong displacement fields with low acoustic losses as a function of WO3 thicknesses. For all the deposited layers, the measured Young’s moduli and Poisson’s ratios are 8 GPa and 0.5, respectively

Structural characterization of LaCoO3 thin films grown by Pulsed Laser Deposition

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Structural Characterization of LaCoO3 Thin Films Grown by Pulsed Laser Deposition

Thin films of crystallized LaCoO3 were grown on Si substrate by Pulsed Laser Deposition at different temperatures (750°C, 850°C and 1000°C). The structural characterization of the LaCoO3 thin films was done by combining several techniques: Scanning Electron Microscopy (SEM), Atomic Force Microscope (AFM), Transmission Electron Microscopy (TEM) and Grazing Incidence X-Ray Diffraction (GIXRD). The thin films crystallized in the expected rhombohedral phase whatever the deposition temperature, with an increase of crystallite size from 70 nm at 750°C to 100 nm at 1000°C, and an average thickness of the thin films of less than 200 nm. At 850°C and 1000°C, the thin films are crack-free, and with a lower number of droplets than the film deposited at 750°C. The grains of LaCoO3 film deposited at 850°C are columnar, with a triangular termination. At 1000°C, an intermediate layer of La2 Si2 O7 was observed, indicating diffusion of Si into the deposited film

Vanadium valency and hybridization in V-doped hafnia investigated by electron energy loss spectroscopy

PACS. 61.50.Nw Crystal stoichiometry – 71.28.+d Narrow-band systems; intermediate-valence solids – 78.70.Dm X-ray absorption spectra,