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The characterization of structures currently used in thin film and nanotechnology constitutes an extreme challenge to the techniques of surface and materials analysis presently available, often going beyond their actual capabilities. In particular, their detection sensitivities and spatial resolution may not be sufficient to cope with the requirements posed by those technologies. The application of modern, commercial 3D atom probe tomographic (APT) instruments has considerably extended the range of analytical problems that can be tackled and solved. APT combines the quantitative and highly sensitive characterization of the chemical content of materials with a three-dimensional registration of elemental distributions, achieving potentially atomic spatial resolution both laterally and in-depth. While the first part of this contribution, published in the last issue, has presented the basic physical and instrumental principles of APT, this second part will discuss two selected applications from magnetic storage and silicon nanotechnology. They will serve to illustrate the new analytical capacities provided by atom probe tomography for the investigation of thin-film and nano-scale structures. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Salih K.S.M.,University of Kaiserslautern | Mamone P.,University of Kaiserslautern | Dorr G.,University of Kaiserslautern | Bauer T.O.,University of Kaiserslautern | And 10 more authors.
Chemistry of Materials | Year: 2013

Extremely small, monodisperse, and spheric maghemite (γ-Fe 2O3, 2-3 nm) and manganese (4-7 nm), cobalt (3-5 nm), and zinc ferrite (5-7 nm) nanocrystals are directly accessible on a large scale starting from inexpensive metal powders and octanoic acid by thermolysis in a high-boiling solvent. Bigger particle size is obtainable by prolonged reaction time according to the Ostwald ripening principle. The superparamagnetic nanocrystals and their assembly have been characterized by transmission electron microscopy, powder X-ray diffraction, Mössbauer spectroscopy, magnetic measurements, and energy-dispersive X-ray spectroscopy. © 2013 American Chemical Society. Source

Using examples from the adhesive bonding and ultrasonic welding technique shows how various methods of vacuum-assisted analysis can contribute to explain joining mechanisms and derive optimization potentials for strength and durability of composites. Employing Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) to characterize epoxy-adhesives, locally resolved and quantitative structural informations can be achieved. Multivariate data analysis methods prove to be very helpful here. Analytical investigations with high spatial resolution at the interface of ultrasonic welded aluminium joints provide structural and chemical data and allow the characterization of the bonding zone in detail. Thus the physical and chemical processes occurred during the welding process can be reconstruct. The increase of strength and longterm durability of ultrasonic- or induction welded hybrid joints (aluminium and carbon-fibre reinforced thermoplastics) can be attributed to micromechanical interlocking of the CF-matrixpolymer with Al-oxide-layer. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Wahl M.,Institute fur Oberflachen und Schichtanalytik GmbH | Gnaser H.,Institute fur Oberflachen und Schichtanalytik GmbH | Kopnarski M.,Institute fur Oberflachen und Schichtanalytik GmbH
Vakuum in Forschung und Praxis | Year: 2013

Atom probe tomography has gained considerable importance in the past couple of years due to the steadily increasing demands on the capabilities of analytical tools for nanotechnology. Presently available preparation and instrumental methods allow the application of atom probe tomography also for technically relevant specimens. This affords a unique analytical approach for a quantitative and highly sensitive characterization of the chemical content of materials; by combining these features with the three dimensional registration of the elemental distributions, atomic spatial resolution can be achieved both laterally and in-depth. For this reason, atom probe tomography is very well suited for the determination of the composition and morphology of crystalline and amorphous materials and nanostructures, and may have an enormous impact on research and development in various areas of material sciences. The first part of this contribution on modern atom probe tomography illustrates the evolution of the technique from its beginnings in the 1950s to the presently available commercial instruments. In the course of this overview, the basic physical and instrumental concepts will briefly be outlined. The second part will concentrate on the presentation of selected, current applications; these examples will serve also to emphasize some of the limitations of atom probe tomography. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

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