Search results for "AUGER"
showing 10 items of 144 documents
Iron deposition on TiO2(110): effect of the surface stoichiometry and roughness
1999
Abstract Characterizations of ultra-thin iron films deposited on TiO 2 (110) surfaces with different stoichiometries, roughnesses and crystallinities have been carried out by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). For a high initial roughness of the substrate, a 2D growth mode is observed up to three monolayers. But, if the initial roughness is low, clusters grow on the TiO 2 surface. Whatever the initial surface stoichiometry, electronic exchanges occur between titanium and iron leading to a reduction of titanium and an oxidation of iron. This interaction between iron and titanium dioxide surface takes place only at the interface between the metal and…
Structural properties of the quaternary Heusler compound Co2 Cr1−x Fex Al
2006
Abstract The structural and chemical properties of the quaternary Heusler compound Co2 Cr1−x Fex Al were investigated comparing powder and bulk samples. The long range order was determined by means of X-ray diffraction, while the site specific (short range) order was proved by the extended X-ray absorption fine structure method (EXAFS). The chemical composition was analysed by means of X-ray photo emission spectroscopy (XPS) combined with Auger electron spectroscopy (AES) depth profiling. The results from these methods are compared to get a detailed idea about the differences between surface and bulk properties and appearance of disorder in such alloys.
Relationships between strain, microstructure and oxide growth at the nano- and microscale
2008
In the present article, the relationships between oxidation processes, surface strains and the microstructure of duplex stainless steels were investigated. Specimens were oxidized at 500 °C under secondary vacuum for 1 h to form a thin oxide film (thickness in the range of 20-50 nm). Such specimens were considered as the model system for developing novel methods of analysis in understanding the behavior of passive films. The interfacial strain field after oxidation was measured experimentally at the microscale using the point grid method. On the other hand, the chemical composition of the oxide film was determined at the submicroscopic scale by means of local scanning Auger spectroscopy (wi…
Fabrication of layered nanostructures by successive electron beam induced deposition with two precursors: protective capping of metallic iron structu…
2011
We report on the stepwise generation of layered nanostructures via electron beam induced deposition (EBID) using organometallic precursor molecules in ultra-high vacuum (UHV). In a first step a metallic iron line structure was produced using iron pentacarbonyl; in a second step this nanostructure was then locally capped with a 2-3 nm thin titanium oxide-containing film fabricated from titanium tetraisopropoxide. The chemical composition of the deposited layers was analyzed by spatially resolved Auger electron spectroscopy. With spatially resolved x-ray absorption spectroscopy at the Fe L₃ edge, it was demonstrated that the thin capping layer prevents the iron structure from oxidation upon e…
A CEMS/AES study of the passivation of iron
1989
The passivation of iron and steel (DIN 1623) was studied by integral and depth selective conversion electron Mossbauer spectroscopy and Auger electron spectroscopy. Thickness and phase composition of the passive layer formed in sulphate solution and in a phosphate buffer were determined in dependence on the anodic potential and the duration of the passivating procedure. The experimental results lead to the conclusion that not the whole oxidic layer is responsible for the passivity but only a very thin intermediate layer formed between the cubic substrate and the rhombic oxide (γ-FeOOH) cover.
Angular-resolved electron spectroscopy from (110) surfaces of ternary Ce-based intermetallics: CePd2Si2 and CeNi2Ge2
1997
Investigations of electronic properties were carried out for the ternary Ce-based intermetallic systems CeT2X2 (T = Ni, Pd; X = Ge, Si). To produce well-ordered and atomically clean surfaces, preparation is carried out in UHV. The polycrystalline substance was evaporated on a W(110) substrate with subsequent annealing. The single-crystalline layers obtained are characterised by MEED (thickness), AES (surface stoichiometry), LEED and SEM (surface structure). For electron-spectroscopic investigations, ARUPS (angle-resolved photoemission spectroscopy) was used. In the photoemission spectra, dispersion effects could be detected by variation of the detection angle.
Preparation by radio-frequency magnetron co-sputtering and characterization of thin films of lanthanum–strontium ferromanganites
2005
Abstract (La 0.8 Sr 0.2 )(Mn 1 − y Fe y )O 3 ± δ films with y = 0, 0.2, 0.5, 0.8 and 1, a few hundred nanometers thick, were deposited onto polycrystalline yttria-stabilized zirconia YSZ by a magnetron co-sputtering technique using individual targets of La 0.8 Sr 0.2 MnO 3 and La 0.8 Sr 0.2 FeO 3 . The deposition parameters, substrate temperature and gas pressure, were studied by scanning electron microscopy, energy dispersive X-ray spectrometry, X-ray diffraction and interferential microscopy for their effects on the morphological, chemical, topographic and crystallographic properties of films and YSZ-film interfaces. (La 0.8 Sr 0.2 )(Mn 1 − y Fe y )O 3 ± δ thin films were found to be …
The growth of oxide platelets on nickel in pure oxygen. II. Surface analyses and growth mechanism
1993
The structural properties of NiO platelets emerging from a primary oxide layer by oxidation of pretreated nickels in pure oxygen between 650 and 800° C have been investigated in relation with the initial metallic layers and the primary oxide. Surface composition and segregation of impurities were also studied by X-ray photoelectron spectroscopy and Auger electron spectroscopy. Textural properties and structural orientation of both the primary oxide layer and the platelets were analyzed by X-ray diffraction and transmission electron microscopy. Platelets grew along {111} planes, leading to elliptical or semicircular bicrystals. The driving force for the present type of growth originates from…
Technical Note:Study of the Cl−-Induced Breakdown of the Passive Layer on Steel
1991
Abstract The Cl−-induced breakdown of the passive layer on a standard steel has an induction time that increases in a nearly linear fashion with the previous holding time (at the passivation potent...
Effect of the surface stoichiometry on the interaction of Mo with TiO2 (110)
2000
Abstract Molydenum has been deposited at room temperature on (110) TiO2 surfaces with different stoichiometries, roughnesses and crystallinities. Whatever the substrate preparation is, in-situ Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS) studies as well as ex-situ atomic force microscopy (AFM) and reflexion high-energy electron diffraction (RHEED) studies reveal a Stranski–Krastanov growth mode: the completion of three monolayers followed by islands growth is observed in every case. The three monolayers are always composed of amorphous molybdenum oxide with an oxidation state of molybdenum less than IV. The oxidation of the molybdenum layers generates Ti3+ an…