Pt/Ti metallisation bilayers are used as bottom electrodes for ferroelectric thin films. During deposition of the ferroelectric films, these electrodes are exposed to elevated temperatures causing modifications of the Pt/Ti bottom electrode. Diffusion and oxidation of the Ti adhesion layer have been studied by the application of factor analysis to AES depth profile data and by RBS. Factor analysis was employed to extract the chemical information from the measured AES spectra and to derive semiquantitative depth profiles of the identified material compounds. RBS was used to obtain the quantitative depth distribution of the elements. By the combination of both methods, diffusion and oxidation processes were observed and could be precisely describe.
We present experimental results and theoretical simulations of the adsorption behavior of the metal-organic precursor Co2(CO)8 on SiO2 surfaces after application of two different pre-treatment steps, namely by air plasma cleaning or a focused electron beam pre-irradiation. We observe a spontaneous dissociation of the precursor molecules as well as auto-deposition of cobalt on the pre-treated SiO2 surfaces. We also find that the differences in metal content and relative stability of these deposits depend on the pre-treatment conditions of the substrate. Transport measurements of these deposits are also presented. We are led to assume that the degree of passivation of the SiO2 surface by hydroxyl groups is an important controlling factor in the dissociation process. Our calculations of various slab settings using dispersion corrected density functional theory support this assumption. We observe physisorption of the precursor molecule on a fully hydroxylated SiO2 surface (untreated surface) and chemisorption on a partially hydroxylated SiO2 surface (pre-treated surface) with a spontaneous dissociation of the precursor molecule. In view of these calculations, we discuss the origin of this dissociation and the subsequent autocatalysis.
It is proposed in this study to observe the influence of P2O5 on the formation of the apatite-like layer in a bioactive glass via a complete PIXE characterization. A glass in the SiO2-CaO-P2O5 ternary system was elaborated by sol-gel processing. Glass samples were soaked in biological fluids for periods up to 10 days. The surface changes were characterized using Particle Induced X-ray Emission (PIXE) associated to Rutherford Backscattering Spectroscopy (RBS), which are efficient methods for multielemental analysis. Elemental maps of major and trace elements were obtained at a micrometer scale and revealed the bone bonding ability of the material. The formation of a calcium phosphate-rich layer containing magnesium occurs after a few days of interaction. We demonstrate that the presence of phosphorus in the material has an impact on the development and the formation rate of the bone-like apatite layer. Indeed, the Ca/P atomic ratio at the glass/biological fluids interface is closer to the nominal value of pure apatite compared to P2O5 free glasses. It would permit, in vivo, an improved chemical bond between the biomaterials and bone.
We present results on the longitudinal spin Seebeck effect (LSSE) shown by semiconducting ferrimagnetic NiFe2O4/Pt films from room temperature down to 50K base temperature. To the best of our knowledge, this is the first observation of spin caloric effect in NiFe2O4 thin films. The temperature dependence of the conductivity has been studied in parallel to obtain information about the origin of the electric potentials detected at the Pt coverage of the ferrimagnet in order to distinguish the LSSE from the anomalous Nernst effect. Furthermore, the dependence of the LSSE on temperature gradients as well as the influence of an external magnetic field direction is investigated.
For a long time, RBS and PIXE techniques have been used in the field of cultural heritage. Although the complementarity of both techniques has long been acknowledged, its full potential has not been yet developed due to the lack of general purpose software tools for analysing the data from both techniques in a coherent way. In this work we provide an example of how the recent addition of PIXE to the set of techniques supported by the DataFurnace code can significantly change this situation. We present a case in which a non homogeneous sample (an oxidized metal from a photographic plate -heliography- made by Niepce in 1827) is analysed using RBS and PIXE in a straightforward and powerful way that can only be performed with a code that treats both techniques simultaneously as a part of one single and coherent analysis. The optimization capabilities of DataFurnace, allowed us to obtain the composition profiles for these samples in a very simple way.
Bismaleimide (BMI) are thermosetting polymers mainly used in aerospace applications having properties of dimensional stability, low shrinkage, chemical resistance, fire resistance, good mechanical properties and high resistance against various solvents, acids, and water. BMI is commercially available as Homide 250. BMI coating has also been used for the corrosion protection. Metallization (AL) of BMI using vacuum evaporation was done which serves the purpose of prevention of space charge accumulation in aircraft bodies. Addition of inorganic materials like metal oxides can influence the properties of the polymer as an inorganic-organic composite. The organic-ionorganic composites have wide applications in electronics, optics, chemistry and medicine. Titanium dioxide (TiO2, Titania) has a wide range of applications starting from photocatalysis, dye-sensitized solar cells to optical coatings and electronics. A BMI-TiO2 composite was prepared by chemical route. Atmospheric Plasma Jet (APPJ) using Helium gas was also treated on BMI. XRD and FTIR studies of the composite system prepared at different temperatures showed its crystalline and structural configuration.
U. Scheithauer
,W. Hosler
,R. Bruchhaus
.
(2015)
.
"Combined AES/Factor Analysis and RBS Investigation of a Thermally Treated Pt/Ti Metallisation on SiO2"
.
Uwe Scheithauer Dr.
هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا