The development of tunable spherical aberration (Cs) imaging correctors for medium-voltage transmission electron microscopes (TEM) offers new opportunities for atomic-scale in-vestigations of materials. A very interesting class of microstructures regarding a variety of dif-ferent physical properties are the transition metal dichalcogenide misfit layer compounds exhibit-ing a high density of incommensurate interfaces due to their stacked nature. In the present study, the benefits coming along with the set-up of negative CS imaging (NCSI) conditions (in TEM) are demonstrated by means of different examples regarding local inhomogeneities in (PbS)1.14NbS2 crystals that can not be dissected in such detail by averaging x-ray techniques.

We use off-axis electron holography in the transmission electron microscope (TEM) to study magnetic flux closure (FC) states in self-assembled nanoparticle rings that each contain between five and eleven 25-nm-diameter Co crystals. Electron holograms are acquired at room temperature in zero-field conditions after applying chosen magnetic fields to the samples in situ in the TEM by partially exciting the conventional microscope objective lens. Mean inner potential contributions to the phase shift are determined by turning the samples over, and subsequently subtracted from each recorded phase image to obtain magnetic induction maps. Our results show that most nanoparticle rings form FC remanent magnetic states, and occasionally onion-like states. Although the chiralities (the directions of magnetization) of the FC states are determined by the shapes, sizes and positions of the constituent nanoparticles, reproducible magnetization reversal of each ring can be achieved by using an out-of-plane magnetic field of between 1600 and 2500 Oe.

For perfect crystal, diffuse scattering is mostly inelastic due to phonons, plasmons and other processes. Thermal diffuse scattering or phonon scattering can lead to large effects in the electron diffraction pattern especially near second order phase transition where phonon softening occurs. Additionally, elastic diffuse scattering comes from structural deviations from a periodic lattice. These structural deviations can be defects, partial ordering of otherwise disordered structure or structural fluctuations. By studying diffuse scattering we can obtain information about the crystal imperfections and dynamics which can not be obtained from other characterization methods.

In this work, we show how the Z-contrast annular dark field scanning transmission electron microscopy technique can provide reliable dopant profiles in ultra shallow junctions in Si. Dopant profiles obtained with this technique are compared with those obtained by spectroscopic techniques like secondary ion mass spectroscopy and medium energy ion scattering.

A new technique called Energy-loss Magnetic Chiral Dichroism (EMCD) has recently been developed [1] to measure Magnetic Circular Dichroism (MCD) in the Transmission Electron Microscope (TEM) with a spatial resolution of 10 nm. This novel technique is the TEM counterpart of X-ray Magnetic Circular Dichroism (XMCD), which is widely used for the characterization of magnetic materials with synchrotron radiation.

In this paper we describe several experimental methods which can be used to measure the EMCD signal [1-5] and give a review of the recent improvements of this new investigation tool. The dependence of the EMCD on several experimental conditions (such as thickness, relative orientation of beam and sample, collection and convergence angle) is investigated in the transition metals Iron, Cobalt and Nickel. Different scattering geometries are illustrated; their advantages and disadvantages are detailed, together with current limitations. The next realistic perspectives of this technique will consist in measuring atomic specific magnetic moments, using suitable spin and orbital sum rules [4,6], with a resolution down to 2-3 nm.

Indium antimony (InSb) has been deformed in compression under gaseous confining pressure (Paterson apparatus) above and below the brittle to ductile transition occurring around 150°C. Thin foils have been prepared from the deformed samples and dislocations were characterized with conventional TEM as well as LACBED. This paper focuses on the room temperature deformation microstructures which appeared to be extremely complex with the observation of very well arranged network of perfect and partial dislocations. In such case, the traditional dislocation extinction conditions were extremely difficult to apply and only the use of the LACBED technique uncovered the nature of the observed dislocations and gave further insight to their interactions, revealing in particular the presence of partial dislocation dipoles. These original observations suggest a change of deformation mechanism at the brittle to ductile transition temperature.

A novel method for the structurally identification of a nanocrystal from a single high resolution (HR) transmission electron microscopy (TEM) micrograph is described. Components of this method are demonstrated on both experimental and simulated HRTEM images. On the experimental side, the structural information that can be extracted from a HRTEM image is the projected reciprocal lattice geometry, the plane symmetry group, a few structure factor amplitudes and phases, and an outline of the projected atomic structure to the limited resolution of the HRTEM (via a Fourier synthesis of the structure factors). Searching for this information in a comprehensive database and matching it with high figures of merit to that of candidate structures should allow for highly discriminatory identifications of nanocrystals, even without additional chemical information as obtainable in analytical TEMs.

The Au nano-particles are deposited on the metal oxide substrate, TiO2 and CeO2, and the structure of the Au particles and Au-metal oxide interface was observed by TEM and HAADF-STEM. It was found that the growth of Au particles on TiO2 and CeO2 by heating treatment is suppressed in the reductive atmosphere. The HAADF-STEM observation was carried out and the atomically resolved HAADF-STEM images in profile-view are successfully obtained for Au/TiO2 and Au/CeO2 samples. The Au particles tend to supported on CeO2 surface with the flat interface compared to the TiO2 substrate. The incoherent interface is observed for the Au particles-CeO2 interface.

Low energy electron microscopy (LEEM) operated at incident electron energies just above the “mirror” mode is used to image Si-based test devices. Significant p- vs. n- doping contrast is observed, even when the structures are covered with a ∼3.5 nm thermal oxide. The contrast arises from a difference in surface potential between the two regions and is related to both p-n work function differences and electron-beam-induced charging of the oxide. The results show that the LEEM is capable of characterizing pn junctions without complicated sample preparation and that it is a promising technique for rapid, non-destructive imaging of microelectronic devices.

The spatial distribution of flux pinning centers in YBa2Cu3O7 (YBCO) coated conductors significantly affects the conductive properties. Nanoparticles acting as pinning centers can be intentionally introduced into the structure by chemical doping. In this study, a Dy-doped YBa2Cu3O7-x coated superconductor was investigated and the particle composition was found to be as (YsDy1-s)2Cu2O5 with s ∼0.6. A tomographic tilt series was acquired using a scanning transmission electron microscope (STEM) to determine the 3-D distribution of nanoparticles. In the investigated sample area, 71 particles were located with a particle size distribution ranging between 13 and 135 nm. The distribution uniformity and size of the particles appeared to be dependent on the grain boundary network structure. Large particles were observed to be located on grain boundaries indicating that fast grain boundary diffusion may determine the particle size.

Diffraction microscopy (or diffractive imaging) with iterative phase retrieval was performed using a low-energy (20-keV) electron beam to verify the possibility of high-resolution imaging with low specimen damage. Diffraction patterns of fine and uniform multi-wall carbon nanotubes (MWCNT) were recorded without a post-specimen lens. One- and two-dimensional phase retrievals were processed from the diffraction pattern alone. The reconstructed object images reflected the characteristic structure of the MWCNT. These results show the possibility of high-resolution imaging with a low-energy electron beam.

This paper presents investigations of magnetization configuration evolution during in-situ magnetic processes in materials exhibiting planar and perpendicular magnetic anisotropy. Transmission electron microscopy has been used to perform magnetic imaging. Fresnel contrasts in Lorentz Transmission Electron Microscopy (LTEM) and phase retrieval methods such as Transport of Intensity Equation (TIE) solving or electron holography have been implemented. These techniques are sensitive to magnetic induction perpendicular to the electron beam and can give access to a spatially resolved (resolution better than 10 nm) mapping of magnetic induction distribution and could be extended to dynamical studies during in-situ observation. Thin foils of FePd alloys with a strong perpendicular magnetic anisotropy (PMA) and self-assembled Fe dots are presented. Both are studied during magnetization processes exhibiting the capacities of in-situ magnetic imaging in a TEM.

The microstructural defects of nanocrystalline SnO2 thin films prepared by pulsed laser deposition have been investigated using transmission electron microscopy, high-resolution transmission electron microscopy and Raman spectroscopy. Defects inside nanocrystalline SnO2 thin films could be significantly reduced by annealing the SnO2 thin films at 300 °C for 2 h. High-resolution transmission electron microscopy showed that stacking faults and twins were annihilated upon annealing. In particular, the edges of the SnO2 nanoparticles demonstrated perfect lattices free of defects after annealing. Raman spectra also confirmed that annealing the specimen was almost defect-free. By using thermal annealing, defect-free nanocrystalline SnO2 thin films can be prepared in a simple and practical way, which holds promise for applications as transparent electrodes and solid-state gas sensors.

Recent applications of scanned probe microscopy are defined often going hand in hand with improved spectroscopy. These methods can provide information about dynamic response extending down towards the femotsecond time scale for resettable, repeatable phenomena and may thus help to fill the gap in the microscopist's coverage of material behavior. Although the use of photon pulses is best developed, ultra-short electron pulses are now available. Various options are therefore to hand in either transmission electron microscopy or scanning transmission electron microscopy operation for combining the spatial resolution of electrons with the spectral selectivity and precision of photons. With purely photon pump-probe operation, good spatial resolution can perhaps be obtained using the tip field-enhancement effect in scanning probe microscopy (SPM) and has also recently been impressively demonstrated in two-photon photo-electron microscopy (PEEM) operation.

Magnetic thin films of Co80Cr16Ta4 were sputtered onto identical CrMo seed-layers at −200 V bias and 3 different substrate temperatures (150, 200, and 250°C). Energy-filtered transmission electron microscopy (EFTEM) was performed to analyze Cr levels at the grain boundaries as well as inside the grains. These quantitative Cr measurements were used to estimate the local values of magnetocrystalline anisotropy (Ku) and, together with grain size distributions, calculate the product of Ku and the grain volume (KuV), a quantity which is a measure of thermal stability. The results show that the coercivity as well as the percentage of stable grains increased with increasing substrate temperature. The increase in the number of stable grains is produced by the enhancement in the Ku value from Cr depletion of the grain interiors and the magnetic decoupling between the grains from Cr grain boundary segregation.

Ion irradiation has been performed on epitaxial Fe/MgO/Fe magnetic tunnel junctions exhibiting antiferromagnetic exchange coupling. Electron holography and VSM experiments show that the amplitude and the nature of the coupling are modified by the irradiation. We demonstrate that the roughness induced by the irradiation at the Fe/MgO interfaces destroys the AF coupling. The biquadratic coupling experimentally observed in the irradiated samples is the result of the competition between local antiferromagnetic and ferromagnetic coupling. For the largest irradiation doses, the net coupling becomes ferromagnetic.

Detailed computer modelling using finite-element analysis was performed for Si p-n junctions to investigate the effects of surface states and doping concentrations on surface band-bending, surface junction potentials and external patch fields. The density of surface states was determined for our Si specimens with a native oxide layer. Our calculations show that for a typical density of surface states for a Si specimen with a native oxide layer, the effects of external patch fields are negligible and the SE doping contrast is due to the built-in voltage across the p-n junction modified by surface band-bending. There is a good agreement between the experimental doping contrast and the calculated junction potential just below the surface, taking into account surface states, for a wide range of doping concentrations.

The nucleation and growth of Cu2O and NiO islands due to oxidation of Cu-24%Ni(001) films were monitored at various temperatures by in situ ultra-high vacuum (UHV) transmission electron microscopy (TEM). In remarkable contrast to our previous observations of Cu and Cu-Au oxidation, irregular-shaped polycrystalline oxide islands were observed to form with respect to the Cu-Ni alloy film, and an unusual second oxide nucleation stage was noted. Similar to Cu oxidation, the cross-sectional area growth rate of the oxide island is linear indicating oxygen surface diffusion is the primary mechanism of oxide growth.

A study of high-resolution ADF imaging in uncorrected and aberration-corrected STEMs was carried out by multislice simulation. The presence of amorphous layers at the surface of a crystalline specimen is shown to significantly alter the visibility of the atomic columns in ADF images. After propagating through an amorphous layer a portion of the beam passes without any alteration while scattered electrons introduce a Gaussian background. An amorphous layer at the beam entry surface appears to have slightly more of an effect on the ADF image contrast than that of an amorphous layer at the exit surface, and this difference increases with increasing atomic number. With constant crystal layer thickness, the reduction of contrast as a function of increasing amorphous layer is found to have the same behavior, regardless of the thickness of the initial crystal layer thickness.

Gold nanoparticles are observed by high-resolution electron microscopy over a high tilt range equivalent to tomographic data acquisition. It is demonstrated how the lattice resolved contrast can be used to identify the internal multiply-twinned microstructure, as the large number of viewing direction allows to image each of the grain-to-grain displacement vectors in at least one image. Furthermore application of tomographic reconstruction is shown after binarisation of the original images to estimate the external shape from the support of the particle in the case of convex objects.