Epitaxial fe/cu superlattices on Si(111)

We report on the successful epitaxial growth of Fe/Cu superlattices on Si( 111) wafers at room temperature. The superlattices were characterized with x-ray diffraction, conversion electron Mossbauer spectrometry, and selected area electron diffraction experiments. The epitaxial growth is crucially dependent on which element is deposited first on the bare Si( 111)

The epitaxial growth of evaporated cu/caf2 bilayers on si(111)

Successful and unexpected epitaxial growth of Cu/CaF2, bilayers on hydrogen terminated Si(111) wafers by thermal evaporation is reported. The bilayers were characterized with conventional x-ray diffraction experiments, grazing angle incidence x-ray diffraction experiments, rocking curves, and x scans. The growth mode of Cu films on CaF2 epitaxially grown on Si(111) is completely different from that of the Cu film grown directly on Si(111)

Structural and Morphological Characterization of the PP-0559 Kaolinite from the Brazilian Amazon Region

We report a structural and morphological characterization of the natural kaolinite PP-0559, from the Brazilian Amazon region, with the aim to contribute to the understanding of this clay mineral in environmental redox reactions. The triclinic structure was confirmed by transmission electron microscopy and electron diffraction studies. It exhibits oriented crystals, with diameters between 0.2 and 2 mum and about 50 nm of thickness. The anisotropic crystals after orientation were studied by electron paramagnetic resonance as a function of the applied magnetic field. The main EPR absorption lines of the substitutional Fe+3 impurity and radiation induced paramagnetic centers were studied as possible oxidizing centers of kaolinite

ZnO nanoparticle fabrication starting from ultra-high (1:2) PVOH/ZnAc proportion electrospun nanowire mats

<div><p>Abstract: The high versatility of nanostructured ZnO has drawn considerable attention from the scientific community since the second half of the two thousand decade. Within this timeframe, electrospinning became one of the simplest ways to produce nanostructured ZnO. In this work, we present the production and characterization of ZnO nanoparticles obtained from electrospun fiber mats using the highest (1:2) PVOH/ZnAc proportion reported so far. The thermally annealed samples were characterized using , X-Ray Diffraction (XRD), High Resolution Scanning Electron Microscopy (HRSEM), Energy Dispersive X-Ray analysis (EDS) and Cathodoluminescence (CL). The results obtained show that all annealed samples present excess zinc as oxygen vacancies (VO, VO +) or oxygen antisites (OZn) which contribute to a considerable change in the CL spectra. This change evidences the presence of defect levels within the ZnO gap, which might be an indication that our nanoparticles present higher catalytic activity within the visible spectrum.</p></div

La Voz de Asturias : diario de información: Año XI Número 3300 - 1933 Noviembre 14

In this work we present low-field magnetic measurements on multilayers of Fe 1.5 nm and Cu 1.5 nm layers, repeated 10 times, grown on Si~111! and Fe 5 nm/CaF2 40 nm/Si(111), substrates. Magnetic characteristics of a spin-glass phase are exhibited by samples directly grown on Si (111), for which the glass temperatures (TG) depend strongly on the magnetic field. Above TG those samples exhibit a ferromagnetic behavior. In contrast, samples grown on Fe/CaF2 buffer structure also show the spin-glass characteristics, but are antiferromagnetic above TG . This work deals with the fundamental role played by the interface between Fe and Cu for these effects, which is clearly emphasized by the experimental results

Structural change and heteroepitaxy induced by rapid thermal annealing of CaF/sub 2/ films on Si(111)

In this article we show that heteroepitaxial CaF2 films can be induced on Si~111! with a rapid thermal anneal. The change from preferentially oriented polycrystals to a single crystal with type- B epitaxy is visible by different structural techniques. The x-ray photoelectron spectroscopy results indicate the presence of a reacted layer at the CaF2 /Si interface with a pronounced increase of fluorine atoms at this interface. Transmission electron microscopy results show that big structural changes occur due to the thermal pulse

Structural change and heteroepitaxy induced by rapid thermal annealing of CaF/sub 2/ films on Si(111)

In this article we show that heteroepitaxial CaF2 films can be induced on Si~111! with a rapid thermal anneal. The change from preferentially oriented polycrystals to a single crystal with type- B epitaxy is visible by different structural techniques. The x-ray photoelectron spectroscopy results indicate the presence of a reacted layer at the CaF2 /Si interface with a pronounced increase of fluorine atoms at this interface. Transmission electron microscopy results show that big structural changes occur due to the thermal pulse