The optimized performance of Co(CrTaPt) thin-film longitudinal magnetic recording media (for computer hard discs) depends critically on the grain size distribution and on intergranular Cr segregation that magnetically isolates the grains. These microstructural aspects of both model and commercial media have been extensively investigated at ∽1 nm resolution with quantitative elemental mapping by energy-filtered transmission electron microscopy (EFTEM) of Cr, Co, and O, but not Ta and Pt which unfortunately are not amenable to quantitative elemental mapping by EFTEM. Procedures for data acquisition and processing have been refined in order to provide robust methods for measuring intergranular compositions for statistically significant numbers of grains. Figure 1 shows results obtained with a Gatan imaging filter (GIF) interfaced to a LaB6 Philips CM30 for a carbon-capped 25-nm-thick film of Co80Cr16Ta4 grown on a Cr underlayer. Typical acquisition parameters have been described previously. to avoid the Cr underlayer, foil thicknesses t<0.2X are used, including the carbon overlayer (λ = inelastic mean free path ≌100 nm).

Industrial catalysts are often chemically and physically complex systems resulting from many years of technology, science, and art. Successful development of commercial catalysts requires talents of many disciplines including chemistry, chemical engineering, surface science, materials science, and physics. A better understanding of the relationship between catalyst structure and activity can provide a scientific prediction of catalytic properties. The insight gained from catalyst characterization can provide guidance for designing and synthesizing better commercial catalysts. Characterization of industrial catalysts is challenging and expensive; however, it can be highly rewarding in developing commercial catalysts used for manufacturing multibillion-dollar products.

The ultimate goal of catalyst characterization is to correlate the physical, chemical, mechanical, and electronic properties of a catalyst to its activity, selectivity, and stability. in industrial practice, however, because of the complexity of the catalysts, the time limit, and the available resources, the goal of characterizing industrial catalysts is often to elucidate the key performance indicators of a catalyst; these key performance indicators, such as the size and spatial distribution and the composition of the active components and promoters, can then be used to provide guidance for manufacturing better catalysts with desired properties.

Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 – August 2, 2012.

Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 – August 2, 2012.

Grain boundaries in fee metals with low stacking fault energy are known to undergo extended relaxations that can at times lead to a thin layer of a different structure. in Cu, for example, it has been found that Σ3{112}} boundaries relax into a 9R phase or even a bec phase. in this work, we have used high resolution electron microscopy to investigate the atomic structure of Σ99 grain boundaries in mazed bicrystal films of Au. On {001} Ge single crystal substrates, Au bicrystals can be grown in two equivalent {110} orientation variants, related to each other by a 90° rotation about the surface normal. There is equal probability to nucleate either orientation variant in early stages of film formation and since there is no reason for preferential growth, the morphology of the bicrystal film consists of many grains in only two orientations. All grain boundaries are of the type Σ99 and display tilt character.

Thin films 10-200nm thick were grown by physical vapor deposition on {001} Ge substrate at 280°C and followed by annealing at 200°C to relieve stresses.

Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 – August 2, 2012.

Today material science requires the use of increasingly powerful tools in material analysis. The last twenty years have witnessed the development of a number of analytical techniques. However, among these techniques, only a few allow observation and analysis of materials at the nanometer level ; one can mention scanning transmission electron microscopy coupled with electron energy loss spectrometry (STEM-EELS), SIMS and atom-probe techniques. In the STEM combined with electron energy loss spectrometry the spatial resolution can be better than one nanometer on a wide scanning area. However the in-depth spatial resolution is limited by the specimen thickness and therefore strongly depends on samples preparation. On the contrary, In SIMS techniques the in-depth spatial resolution can be as good as one nanometer but the lateral resolution is set by the ion beam diameter.

In this work, the correlation between composition and relative evaporation field was investigated by tracking the statistics of multi-hit detector events in atom probe tomography (APT). This approach is applied systematically to a GaN-based nitride heterostructure with five AlxGa1−xN layers of varying Al composition. The relative field evaporation and the percentage of multi-hit events were found to increase with higher Al concentration. Furthermore, the comparison of the relative evaporation fields of AlN with respect to the constituent ions is found to be less than GaN with respect to its constituent ions. Despite equivalent compositions between opposing interfaces of the same AlxGa1−xN interlayer, the rate of change in multiplicity exhibits a consistent asymmetric trend with a steeper slope across the AlxGa1−xN/GaN interface compared to the GaN/AlxGa1−xN interface. The AlxGa1−xN/GaN heterostructure serves as a test structure for exploring field evaporation and neighborhood chemistry, which can be applied to any material chemistry and particularly other nitride systems.

Amorphous chalcogenides films coated with certain metals are known to possess a remarkable sensitivity to radiation. Based on these effects they have found several important applications in the production of microcircuits, e.g. as resists in photo- and electron beam lithography. A variety of chalcogenides in combination with a range of metals has been extensively investigated with regard to potential applications in the fabrication of semiconductor devices.

The objectives of the present project are to extend knowledge of the behaviour of amorphous chalcogenides in contact with metals. This includes studying the metal diffusion process, understanding the film-electron beam interaction process and evaluating the potential of the metal lines formed by the electron beam in fabrication of photomasks for the production of higher densities of silicon microcircuits.

In recent years, a number of different groups(1) have investigated and reported on implementing Web-based controls for SEMs and TEMs. Through telemicroscopy, as the field is often known, they have demonstrated that expensive microscopy resources can be shared and the experience of remote experts utilized in an efficient, cost-effective manner. Up to this point most technological demonstrations of telemicroscopy have been implemented as retrofits to existing microscopes. As retrofits, these demonstrations had limitations which a system designed from day one as a networked instruments could avoid. present here details of an ongoing project at R.J. Lee Instruments to redesign the software interface to our Personal SEM product around a TCP/IP link between the SEM hardware and the user interface. All communications between the SEM and console, including commands and image data are transmitted over a single 10-BaseT Ethernet link using the connection-oriented TCP protocol.

Practical analyses of the structures of ultrathin multilayers in tunneling magneto resistance (TMR) and Magnetic Random Access Memory (MRAM) devices have been a challenging task because layers are very thin, just 1–2 nm thick. Particularly, the thinness (∼1 nm) and chemical properties of the AlOx barrier layer are critical to its magnetic tunneling property. We focused on evaluating the current TEM analytical methods by measuring the thickness and composition of an AlOx layer using several TEM instruments, that is, a round robin test, and cross-checked the thickness results with an X-ray reflectometry (XRR) method. The thickness measured by using HRTEM, HAADF-STEM, and zero-loss images was 1.1 nm, which agreed with the results from the XRR method. On the other hand, TEM-EELS measurements showed 1.8 nm for an oxygen 2D-EELS image and 3.0 nm for an oxygen spatially resolved EELS image, whereas the STEM-EDS line profile showed 2.5 nm in thickness. However, after improving the TEM-EELS measurements by acquiring time-resolved images, the measured thickness of the AlOx layer was improved from 1.8 nm to 1.4 nm for the oxygen 2D-EELS image and from 3.0 nm to 2.0 nm for the spatially resolved EELS image, respectively. Also the observed thickness from the EDS line profile was improved to 1.4 nm after more careful optimization of the experimental parameters. We found that EELS and EDS of one-dimensional line scans or two-dimensional elemental mapping gave a larger AlOx thickness even though much care was taken. The reasons for larger measured values can be found from several factors such as sample drift, beam damage, probe size, beam delocalization, and multiple scattering for the EDS images, and chromatic aberration, diffraction limit due to the aperture, delocalization, alignment between layered direction in samples, and energy dispersion direction in the EELS instrument for EELS images. In the case of STEM-EDS mapping with focused nanoprobes, it is always necessary to reduce beam damage and sample drift while trying to maintain the signal-to-noise (S/N) ratio as high as possible. Also we confirmed that the time-resolved TEM-EELS acquisition technique improves S/N ratios of elemental maps without blurring the images.

Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 – August 2, 2012.

Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 – August 2, 2012.

Extended abstract of a paper presented at Microscopy and Microanalysis 2005 in Honolulu, Hawaii, USA, July 31--August 4, 2005