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The implantation-induced defects of crystalline silicon implanted with helium ions to a dose of 5 × 1016/cm2 at 600 °C were investigated. The sample was analyzed by transmission electron microscopy and high-resolution electron microscopy. Faceted cavities are observed in the damaged layer. Concurrently the distribution of interstitial-type defect clusters was investigated by conventional electron microscopy in bright and dark field. Many rod-like defects, which belong to {1 1 3}, {1 1 1} and (−2 0 0), are formed in the end of the projected range. In front of the damaged layer, some ribbon-like defects are formed, which belong to 〈2 0 0〉, 〈1 −1 1〉 and 〈1 3 −3〉. The possible reasons of the observed defect clusters are discussed.

This work presents our recent findings that a small addition (0.5 at. %) of Cr to FeCo–2V alloy leads to a great improvement in creep resistance. High resolution electron microscopy was applied to study microstructural evolution of the Cr added alloy during the creep process performed at 600 °C under 200 MPa. At an initial step of the creep, there appear plate-like precipitates with bcc/fcc structure as well as some rod-like ones with hcp structure. A coherent relationship is identified between the precipitates and bcc FeCo matrix. With prolonging the creep, the rod-like hcp precipitates are revealed to remain in the bcc matrix, showing a good stability under the creep condition and in turn resulting in piling-up of dislocations to a great extent around the precipitates. In addition, the Cr added alloy is shown to have a large stress exponent of 8.4, indicating a strong interaction between dislocations and the hcp precipitates.

We report on the design, fabrication and optical performance of gain mirrors in single crystal diamond substrates for vertical external cavity surface emitting lasers (VECSELs). VECSELs have gained attention recently due to their potential for high emission power in single mode with low beam divergence, yet their maximum output power remains typically limited due to thermal roll-over resulting from insufficient heat dissipation. In order to increase the heat transfer, we exploit the excellent thermal conductivity of single crystal diamond, which is assembled in direct contact with the active structure. The optical cavity is hereby defined by an output coupler and a high reflection grating structure etched into the diamond surface. We here present the design and microfabrication of a diffraction grating that was optimized to reflect light into the 0th order, therefore combining the role of a gain mirror and a heatsink at the same time. Our process involved metal mask deposition onto the diamond surface, e-beam lithography and reactive ion etching. Characterization showed reflection above 95% at a center wavelength of 1550 nm, potentially allowing the integration of the diamond mirror into a vertical external cavity surface emitting laser.

Aberration-corrected electron microscopes currently dominate the high-resolution scene but they are not the only instruments that can provide such information. Other techniques are attracting attention, notably ptychography and the use of phase plates. Moreover, operation of these aberration-corrected microscopes at their ultimate performance raises questions that are still under discussion. We note too that correctors can be useful for tasks other than correction, such as vortex beam creation. To conclude, the specialized role of electron mirrors is recalled.

Experiments on absorption of TmCl3 and Tm(NO3)3 from dry acetonitrile and aqueous solutions, respectively, were performed using carboxylated multiwalled carbon nanotubes with conic and cylindrical displacement of graphene layers. Using HAADF TEM imaging and EDX spectroscopy it was found that in the first case the chemisorption with complex compound formation with oxygen from carboxylated MWCNTs takes place while in the later this process is hampered by kinetic factor and side reactions with water. The data obtained are in good agreement with results of thermal-mass spectral and elemental CHNSO analysis. This particularity allows using transmission electron microscopy and related techniques for direct surveying of light atoms-containing groups on the surface of carbon materials. In the case of carboxylated cylindrical and conic MWCNTs it demonstrate that nanotubes in the second case are uniformly covered by functional groups while in the first – near the ends of tubes and the local defects along the surface.

As reported in our previous works, a Mg-7Gd-5Y-1Nd-0.5Zr alloy recently developed exhibited remarkable age-hardening responses and excellent mechanical properties at both room and elevated temperatures. In Mg-7Gd-5Y-1Nd-0.5Zr alloy, the β precipitate phase was assumed to be one of the main strengthening phases in peak-aged samples. This study aimed to determine the crystal structure and orientation relationship of the β precipitate phase in Mg-7Gd-5Y-1Nd-0.5Zr alloy using transmission electron microscopy and high-resolution electron microscopy. The results indicated that the β precipitate had a face-centered cubic structure with a lattice parameter of a=2.22 nm. The orientation relationship between the β precipitate phase and the α-Mg matrix was ( 1 ¯ 12 ) β / / ( 1 ¯ 100 ) α , [ 110 ] β / [ 0001 ] α . The β plates formed on prismatic planes could play an important role in alloy strengthening by proving effective barriers to gliding dislocations. A single β plate often contained several domains of ( 1 1 ¯ 1 ) β twin-related variants. A composition of Mg5(Y0.4Gd0.4Nd0.2) was suggested for the β phase in Mg-7Gd-5Y-1Nd-0.5Zr alloy.

Twin boundary (TB) and twinning dislocations (TDs) in { 10 1 ¯ 1 } twins in deformed polycrystalline cobalt (Co) were studied by high-resolution electron microscopy. The { 10 1 ¯ 1 } TB tends to be flat and a mirror plane. The observed TD was characterized directly from the experimental image by the circuit-mapping method and predicted by the topological model. The observed TD with a localized core can stably exist in { 10 1 ¯ 1 } twins in Co.

High-resolution electron microscopy was applied to analyze the continuous precipitated particles of the γ-Mg 17 Al 12 phase with Pitsch-Schrader OR in the heat-treated AZ91 alloy at 473 K for 8 h. The existence of a continuous precipitated particle with the Pitsch-Schrader OR including the selection of the habit plane and the growth direction in Mg–Al system is rationalized by the constrained coincidence site lattice/constrained complete pattern shift lattice (CCSL/CDSCL) model and the O-lattice theory.

High-resolution electron microscopy is employed to observe the atomic arrangement of very tip of the growing martensite plate and that of the growing bainite. Transition lattice region with a certain dimension (more than a few nm), of which the structure is neither fcc nor bcc, but an intermediate one between fcc and bcc lattice, is found in martensite but not in bainite. Because of this fact, it is concluded that the martensitic transformation is of the shear-type transformation and the bainitic transformation is of the diffusion-type transformation.

The infinite layer compound Ca0.85Sr0.15CuO 2 has been synthesized by the sol-gel technique using the acetate gel route. The compound is found to be single-phasic as evidenced from the powder X-ray and electron diffraction measurements. EDAX analysis confirms the presence of homogenous stoichiometric phase pertaining to the composition Ca 0.85Sr0.15CuO2. High-resolution electron microscopy (HREM) studies reveal interesting defects in the infinite layer frame work of the system. Apart from the usual strain and shear induced defects observed in the lattice, which is common among the perovskite compounds, the main finding is the defect along [0 1 0], occurring due to the intercalation of extra AO layer in the CuO2 plane. Such a defect is accommodated in the lattice by the increase in the interplanar distance (which is basically the c-axis parameter) from 3.2 to 3.4 � in the defective layer. This implies the formation of square pyramidal oxygen co-ordination of copper at the defect site. ? 2005 Elsevier Ltd. All rights reserved.

Boron nitride (BN) nanohorns with various tip angles were synthesized by an arc-melting method, and atomic structure models for BN nanohorns were proposed from high-resolution electron microscopy. Stability and electronic structures of the BN nanohorns were investigated by molecular orbital/mechanics calculations, which indicated that multi-walled BN nanohorns would be stabilized by stacking of BN nanohorns. The energy gaps of the BN nanohorns were calculated to be 0.20∼0.85 eV, which are lower compared to those of BN clusters and nanotubes.

Electron diffraction and high resolution electron microscopy have been used to characterize two new one-dimensional superstructures in the A Rh O system (A = Ca, Sr) related to the 2H-ABO3-type. They are formed by the intergrowth of n A3A′BO6 blocks, showing the Sr4RhO6-type, with A12A′2B8O30 blocks, constituted by two A3O9 and two A3A′O6 layers alternating in the stacking sequence 1:1, leading to the A27A′7B13O60 ( n = 5 ) and A30A′8B14O66 ( n = 6 ) compositions. A crystallographic shear mechanism is proposed to describe the structural relationship between Sr4RhO6 (A3A′BO6-type) and the new superstructures.

High-resolution electron microscopy, mass spectrometry and molecular mechanics/orbital calculations of the boron nitride-based clusters showed the formation of B 36 N 36 and Y@B 36 N 36 . Image simulations of these clusters confirmed the proposed structure model.

Crystal structures of a homologous series of Co-based layered cuprates, CoSr2(Y,Ce)sCu2O5+2s (s=1–3), have been investigated by high-resolution electron microscopy (HREM) and electron diffraction (ED) techniques. For all the three phases ED patterns showed double periodicity along a direction parallel to the CoO layers, indicating a regular alternation of two types of CoO4-tetrahedra chains within the layers. Also seen was ordering of the chains along the layer-stacking direction for the s=1 phase (Co-1212); ED patterns simulated based on the proposed superstructure model well reproduced the observed patterns. For the s=2 (Co-1222) and s=3 (Co-1232) phases in which an additional fluorite-type layer-block is inserted between two CuO2 planes, HREM and ED analysis revealed complete disorder of the CoO4 chains along the layer-stacking direction. This implies that the interlayer ordering is mainly controlled by the distance between the neighboring CoO layers.

The intermetallic phases of the binary system Al/Ni have attracted considerable effort in investigation, because of a wide field of technological applications. In our recent work we have demonstrated the influence of the microstructure on the early interreaction stages. Although the chemical and spatial information obtained by 3D-atomprobe analysis is unrivaled in resolution, identification of observed phases is only possible by use of complementary methods of investigation. The present paper describes the important role of high resolution electron microscopy for indentifying the structural nature of formed phases detected by 3D-atomprobe analysis. An outline of a model which might explain the different reaction paths in Al/Ni observed for different microstructures will be given.

Atomic structures of surface and interface in (Hg,Tl,Pb)-based superconductors were investigated by high-resolution electron microscopy. The interfaces observed in Tl-based superconductors have the disordered region with ∼1 nm thickness, which would be suitable for barrier layers for tunneling junctions. Although the {001} planes of (Hg,Tl)-based oxides are fairly stable, most of the {100} planes are unstable, and atomic rearrangement was often observed. However, the HREM image of Hg 0.5 Tl 0.5 Ba 2 CuO 5 {100} showed the stable Ba–O–Ba layer at the surface, and oxygen atom positions were determined. The present study indicates that the surfaces of the Hg- and Tl-based superconductors are strongly dependent on the crystallographic planes and crystal structures.

In the field of pharmaceutical applications relying on encapsulation of drug by polymer coating, capsules based on biodegradable polymers with mean size of about 500 nm have been obtained by a patented emulsion–diffusion method. The morphology, size and structure of the nanocapsules (NC) control their pharmaceutical properties, especially release of the drug. Here is reported a decisive contribution of transmission electron microscopy (TEM) in revealing the controlled form and size of the NC: mean size values measured by TEM do agree with data obtained by laser granulometry. Moreover, the TEM magnification allows an estimation of the membrane thickness.

Pd 80 Pt 20 and Pd 85 Pt 15 alloys were exposed at 673 K to a hydrogen pressure of 100 MPa for 4 h, which is called hydrogen heat treatment (HHT). After HHT the pressure composition isotherms at 273 K change remarkably and H-diffusion is enhanced. The change can be interpreted by a decomposition into a continuous Pd-rich and an embedded Pt-rich alloy. Direct evidence for this hypothesis is provided for the first time from high resolution electron microscopy. It will be shown that coherent platelets are formed after HHT which are two atomic layers thick and have an average diameter of ∼10 nm. Simulating the contrast observed in the electron microscope shows that the plates are Pt-rich.

Two new decagonal quasi-crystals (D-phases), which have periods of 0.4 and 1.6 nm, respectively, have been found to form with different compositions in conventionally solidified Al–Ni–Ru alloys. The diffraction patterns of these two D-phases display a large number of sharp diffraction spots located at exact tenfold symmetry positions and almost no diffuse streaks, indicating that they are highly ordered quasi-crystals. The D-phase with 0.4-nm periodicity exhibits a pronounced S1-type superlattice order. The D-phase with 1.6-nm periodicity can be formed as a major phase by annealing at around 900°C. By means of high-resolution electron microscopy, the structural characteristics of the D-phase with 1.6-nm periodicity have been revealed.

Atomic displacements and interface reconstructions near a La0.9Sr0.1MnO3‐SrTiO3 interface are studied by use of the focal reconstruction technique applied in high-resolution electron microscopy. By using a quantitative model, column positions are determined with high precision (better than 0.004 nm) by least-squares minimization. A displacement vector map and interatomic distances are calculated. From these a structure model for the interface is proposed. The interface has a facetted shape, where the interatomic distance is modulated. Possible local oxygen deficiency in SrTiO3 near the interface has been observed. q 2000 Elsevier Science Ltd. All rights reserved.

Single decagonal quasicrystals of Al 70 Ni 15 Co 15 were grown by the Czochralski method at Ar atmosphere. The grown crystals were of single decagonal phase without any secondary phases due to the peritectic reaction and contained a large single quasicrystal of cm order size. The high quality and single quasicrystallinity of them were examined by the Laue transmission photography, single crystal X-ray diffraction, and high-resolution electron microscopy investigations.

The possibility of direct detection of doping atoms in the B12 cluster solid by high-resolution electron microscopy (HREM) was investigated by using calculated residual indices and difference images. The HREM images of B12-based rhombohedral boron doped with (Al, Cu) and carbon atoms were calculated at the Scherzer defocus. The difference images of Al2.6Cu1.8B105/B12 and B13C2/B12 showed Al, Cu and C atomic positions clearly at crystal thickness of 3.1 nm. Crystallographic image processing was applied to the experimental image of Al2.6Cu1.8B105, which provided the average Al and Cu atom positions. In addition, HREM images recorded from thin regions (

The n integer members of the A n +2 B n B ′O 3 n +3 homologous series keeping B = B ′=Co the same have been characterized by selected area electron diffraction and high resolution electron microscopy. Its commensurate modulated structure is made up of chains, separated by A atoms, running along the c direction containing a succession of one Co atom ( B ′) in prismatic trigonal sites and n Co atoms octahedrally coordinated sharing faces. All of them can be described as ordered intergrowths of two structures of the end members of the family, 2H–BaCoO 3 ( n =∞) and Ca 3 Co 2 O 6 ( n =1). The modulation observed in all terms can be described as a function of the difference between the c -axis of the Co sublattice with respect to the 2H structure. Members of the series can be obtained by modifying the distance between layers keeping B =Co the same, as shown in (Sr 1− x Ba x ) 6 Co 5 O 15 ( n =4), Sr 5 Co 4 O 12 ( n =3), and (Sr 0.5 Ca 0.5 ) 4 Co 3 O 9 ( n =2).

A study of the structural transformation of catalytically grown carbon nanotubes induced by annealing under high pressure is presented in this paper. These changes have been monitored with the atomic details using high resolution electron microscopy. The transformation from carbon nanotube into quasi-spherical onion occurs in several steps: first, the shell of the nanotube collapses, and then tends to form a sphere and subsequently an onion-like structure. The transformation process and the effect of high pressure on microstructural changes are discussed.

As one of our systematic studies of the modulated structures of a series of new homologous compounds RM O 3 (ZnO) m ( R =Sc, In, Y, and La; M =In, Fe Ga, and Al; m =integer), this paper reports the modulated structure of Fe 2 O 3 (ZnO) 15 ( R =Fe; M =Fe) studied by high-resolution electron microscopy. It is found that the main and satellite spots in the diffraction patterns can be indexed as h a * + k b * + l c * + m q by considering a monoclinic unit cell of a =0.57 nm, b =0.33 nm, c =4.5 nm, and β =92° and a modulation wave vector of q=b * /34.8+c * /2. The possible space groups for the basic structure are C 2, Cm , and C 2/ m , and the possible four-dimensional superspace groups for the modulated structure are C C 2 1 , C Cm 1 , and C C 2/ m 1 1 . The crystal structure of Fe 2 O 3 (ZnO) 15 consists of Fe–O layers interleaved with 16 Fe/Zn–O layers. In the high-resolution image, the modulated structure appeared as zigzag-shaped contrasts among the Fe/Zn–O layers, where Fe is in high concentration. Compared with those of In M O 3 (ZnO) m ( R =In; M =In, Fe and Ga) reported in our earlier paper, the special features of the present modulated structure are the half-periodicity relative shift of the neighboring zigzag-shaped contrasts and the appearance of modulation within the Fe–O layers.

Zeolites are one of the most important materials currently used in the petroleum industry for a wide variety of catalytic transformations. However, they are increasingly being considered for other applications such as for designing quantum-confined materials in their spaces. With such applications in mind, precise characterisation of zeolites and related porous materials has never been more necessary. Here we show how electron diffraction coupled with high-resolution imaging can reveal the detailed fine structure in both the bulk and at the surface of these materials. A variety of case studies are considered which include ETS-10, FAU, LTL and FSM-16.

Surface structures of the (Hg,T1)-based superconducting and related oxides were studied by high-resolution electron microscopy. The {100} planes of the 1201-type structure were found to be stable, and Hg0.5Tl0.5Ba2CuO5 showed a preferred atomic surface consisting of Ba layers. The {001} planes were also stable in HgTlBa2CuOx and TlBa2CaCu2O7. The present work indicates that the stable {100} planes of (Hg,Tl)-based superconducting oxides would be suitable for future device applications.

The microstructural development during annealing in the supercooled liquid region of amorphous Pd 46 Ni 36 P 18 , which is supposedly of phase-separating composition, is compared and contrasted with those of Pd 48 Ni 32 P 20 and Pd 40 Ni 10 Cu 30 P 20 . High resolution electron microscopy showed that the as-quenched alloys were fully amorphous while atom probe field ion microscopy (APFIM) showed random solute distributions, typical of amorphous materials. Annealing in their respective supercooled liquid regions did not result in the formation of compositionally-modulated microstructures prior to the onset of crystallisation.

The damage induced by heavy ion irradiation in a wide palette of materials, extending from metals to insulators, is presented. The damage creation and the track morphology have been investigated by electron microscopy and especially HRTEM when available. It is shown that heavy ion irradiation in the electronic stopping power regime is a very efficient tool to amorphize the solids. But the sensitivity to irradiation of each material is strongly variable since the electronic stopping power threshold for damage creation can vary between 1 and 40 keV/nm. The wide difference in sensitivity to heavy ion irradiation between the insensitive materials such as some semiconductors and insulators and the very sensitive ones like the quartz and some magnetic ferrites is a real challenge for any general model of damage creation in solids.

The internal structure of monodisperse CdS particles was investigated by high-resolution electron microscopy of thin sections prepared with an ultramicrotome. High-resolution images of the thin sections clearly revealed the arrangements and the crystallographic orientations of subcrystals as components of the particles. It was found that the central part of a particle was composed of randomly oriented small subcrystals about 10 nm in diameter, while near the surface of the particle, relatively large subcrystals about 50 nm in maximum width were observed. Furthermore, stacking faults and twins on the {1 1 1} planes were observed in the sections.

In the objective lens alignment in transmission electron microscopy, there is usually some discrepancy between the incident beam directions required to satisfy the voltage-center condition or the coma-free condition. This is because an incident beam direction is found for the reference point conjugate to the screen center, while the reference point is usually not located along the lens-field axis. In this report it is demonstrated that the voltage-center alignment keeping the coma-free condition can be carried out by finding an object point on the lens-field axis. We propose to call this technique a lens-field center alignment. Since most microscopes have the deflector below the objective lens needed for this technique, the lens-field center alignment can be used in most microscopes.

This article reviews the application of high resolution electron microscopy techniques to zeolite structural characterization. Examples given in this article include identification of structural intergrowth, stacking faults and framework projection net from high resolution images. Slow-scan CCD (charge-coupled device) cameras, representing the latest advance in electron microscopy instrumentation, are briefly introduced. Low-dose, high resolution electron microscopy using commercial CCD cameras is discussed. With slow-scan CCD cameras, it is shown that it is possible to directly read off the underlying zeolite structures from experimental high resolution images when suitable image processing techniques are employed. This latest advance greatly enhances the power of high resolution electron microscopy techniques in solving unknown zeolite structures.

A method based on a simulated annealing algorithm is applied for the reconstruction of the projected crystal potential belonging to a periodic high-resolution electron microscopy exit plane wave function. Using simulated exit plane wave functions of GaAs at different specimen thicknesses, the convergence behaviour and the accuracy of the algorithm are investigated. It is demonstrated that the reconstruction is possible even under strongly non-linear scattering conditions at small specimen thicknesses. Further, the convergence of the algorithm to an ambiguous solution beyond a certain specimen thickness is discussed.

A new type of ordered structure in a Ti-48at%Al alloy quenched from the disordered α-Ti phase field has been determined by high-resolution electron microscopy and image simulation. The structure is based on an h.c.p. structure having an orthorhombic unit cell with the lattice parameters a = 0.45 nm, b = 0.28 nm and c = 0.49 nm, and belongs to a B19 type. The B19 TiAl can be described as the AB… stacking of close-packed /(111/) planes in γ-TiAl with an L1 0 structure, and the ordered arrangement of Ti and Al for the B19 structure is interpreted as a local arrangement in the sample.

A cubic member of the M41S family with a three-dimensional pore system, denoted as MCM-48, was synthesised. By combining X-ray powder diffraction (XRD) with high-resolution electron microscopy (HREM), a cubic symmetry with an Ia 3 d space group was determined for the as-synthesised and the calcined MCM-48 material. Upon calcination the unit cell decreased from around 10.09 nm to about 8.1 nm. The overall pore structure was found to be quite unaffected by local variations in the structure and the decrease in the unit cell size upon calcination.

We investigate the effect upon HREM images of the static atomic displacements (SD) present in crystalline alloys with atomic size effect. Our method is to compare pairs of images of the same distributions of atoms (in III–V alloys) calculated with and without taking the SD into account. We show that large differences usually exist between these images, assess them quantitatively, and demonstrate that proper consideration of the SD is essential to achieve reliable composition analysis by HREM, in particular when the ‘chemical mapping’ technique is used. The effect of the SD depends on the specimen thickness and on the objective lens defocus.

C 60 crystals grown by vapour transport may exhibit rough surfaces depending on the cooling conditions at the end of growth. The rough surfaces are due to hillocks of about 0.1–0.3 μm on “002” and “111” faces. Hillocks on “002” faces are square pyramids bounded by “111” surfaces or surfaces deviating from “111”. Hillocks on “111” faces are triangular pyramids bounded by stepped “111” surfaces. The density of crystal defects in as-grown and cleaved crystals is much lower than in crushed crystals. The high density of defects in crushed crystals is induced by specimen preparation. HREM imaging and simulation has confirmed that the cleaved surfaces are clean and free of lattice relaxation.

High-resolution imaging of ordered polymers is described both theoretically and experimentally. The relationship between the actual three-dimensional specimen structure and the resultant two-dimensional image intensity distribution is developed using the multislice formalism. The influence of the electron optical conditions on the image is demonstrated with experimental data, as well as with image simulations. Practical details of specimen preparation, as well as the effects of specimen structural defects on the image, are presented. A significant challenge for polymer microscopists is to minimize the deleterious effects of electron beam damage and to identify image artifacts resulting from damage. Future applications of ultrahigh-resolution capabilities are illustrated with respect to direct imaging of the anisotropic potentials present in covalently bonded materials.

Interface structures in nanocrystalline metals, ceramics, carbon-60 and their composites were compared, using high-resolution electron microscopy, to understand the origin of unusual properties reported systematically by Gleiter and the co-workers. The observations showed that voids are not to be an inherent structure of nanocrystalline materials. Atoms in the grain boundaries are found influenced by the two neighboring crystals just as in usual polycrystalline aggregates. No concrete evidence of nanocrystalline anomaly was found in the density of atoms in the grain boundaries.

Planar defects in the infinite-layer (Sr 1− x Ca x ) y CuO 2 structure are believed to be responsible for superconductivity with T c up to 110 K. In this work we present χ 2 minimization results to best fit a set of through-focal HREM images of such defects. Optimized atomic positions of the defect with an error bar of about 0.1Aare determined. The experimental parameters for simulated defect images such as sample thickness and objective lens defocus are determined by χ 2 fitting of the corresponding experimental HREM images of the matrix.

Core structures of edge and screw dislocations in CoTi were studied by high-resolution electron microscopy (HREM). An HREM image of an edge dislocation showed that the spreading of the dislocation core was limited within a distance of about 1.2 nm. From an HREM image of screw dislocations in CoTi, it was shown that the core was spreading on the (010) plane and the spreading of the core was limited within a distance of about 1.8 nm. It was suggested that the core spreading on the {010} plane, which was different from the slip plane of {110}, affected the abnormal temperature dependence of yield stress of CoTi.

SSZ-25 has been known to have high catalytic activity, but no structure has been reported. A combination of electron microscopy techniques was employed to characterize this new zeolite. This allowed us to determine the unit cell and its relationship to the crystal morphology. The unit cell was hexagonal with a = 1.41 nm and c = 2.52 nm. The individual crystals tend to be thin flakes, and high-resolution electron microscopy (HREM) revealed that this zeolite has a multi-dimensional channel system. The results of this work showed that there are large-pore zeolite channels arranged parallel to the c direction. The HREM results, when taken with other physical characterization methods, confirmed why this zeolite has high catalytic utility.

The direct confirmation of the existence of Cd-stabilized β″″-ferrite prepared as a stable phase in a K2O-Fe2O3-CdO system was done by high-resolution electron microscopy. It was confirmed that the Cd-stabilized β″″-ferrite had a rhombohedral symmetry with lattice constants a = 0.600 and c = 5.026 nm. The structure is composed of an alternate stacking of ion-conductive layers and spinel-like blocks which have six cubic close-packed oxygen layers expressed as · · · A1(BCABCA)B1(CABCAB)C1(ABCABC)A1 · · ·. In addition, twins which had reversed stacking sequences were observed in the spinel-like blocks.

Crystallization behavior of gold-implanted amorphous SiC was studied by high resolution electron microscopy. (1) Prior to crystallization, a concentration fluctuation of gold is induced in the amorphous matrix with annealing. The typical annealing temperature at which evolution of the fluctuation becomes evident is 1023 K. (2) With annealing at 1173 K, crystallization takes place locally and crystallites of β-SiC are formed. It is suggested that this initial crystallization occurs preferentially in the gold-depleted region. (3) With annealing at 1373 K, complete crystallization takes place; gold-implanted amorphous SiC eventually crystallizes into two phases: β-SiC and fcc gold.

A more complete form of contrast transfer theory is derived using a partial coherency approach for both electron holography and conventional high resolution electron microscopy.

The lattice images of ordered and disordered microdomains have been observed directly by high resolution electron microscopy in lead scandium tantalate ceramics. The orientation of crystallization in the ordered region is consistent with the neighbouring disordered regions. The disordered microdomains can be dispersed within the ordered domain and vice versa.

High-resolution electron microscope (HREM) images of ω-phase crystals in Ti-11.1at%Mo alloy single crystals formed by aging are discussed by comparing with the calculated images. The calculation was carried out using the multi-slice method at different defocus values for ω-phase crystals at three different positions in the matrix. It is found that bright spots of HREM images of ω-phase crystals appear at the positions of atoms, which are displaced in the opposite direction and make atom pairs in the model, as was proposed by de Fontaine et al. This fact was previously predicted in 1987. It is also found that bright spots of HREM images appear at the position of atoms, which are not displaced in the model. These results suggest that the proposed model is satisfactory.

The interface between vanadium and the basal plane of sapphire was studied by conventional and cross sectional high resolution electron microscopy (HREM) to clarify the atomic structure of the interface. A 50 nm thick vanadium film was deposited on the (0001) basal plane of sapphire by molecular beam epitaxy (MBE). The TEM observations of the interface were made from three directions: two cross-sectional views (parallel to [1 2 10]Al2O3 and [10 10 ]Al2O3) and plan view (parallel to [0001]Al2O3). From the SADP, the following orientation relationship was obtained: (111)V ‖(0001)Al2O3; [10 1 V ‖[1 2 10]Al2O3. Cross-sectional HREM observations showed the atomic configuration at the interface, and the existence of periodic arrays of geometrical misfit dislocations. Computer simulations show that sapphire is aluminum-terminated at the interface with vanadium.

High-resolution electron microscopy was performed on fine crystals with A-15 type structure prepared by vacuum-deposition of tungsten. The size distribution of the crystals with the A-15 type structure was ranged from 2 to 11 nm and was similar to that of the bcc type structure coexisting in the film, indicating that the nucleation of both structures generated at the same time in the initial stage of growth. The critical grain size of transformation from bcc to A-15 type structure was not observed in the nanometer-sized region. Coalescence of the nanometer-sized crystals with A-15 type structure was observed in the film. It was found that the crystals were connected by stacking faults with displacement vector of 1 2 〈100〉 and nanometer-sized tilt grain boundaries rotated by 30° around the 〈100〉 A-15 axis. It was also implied from the observation that the A-15 structure in the present film was stabilized by some kinds of lattice defects.

In a previous paper, we have shown that high resolution electron microscopy (HREM) is able to reveal nanometric domains in ferroelectric oxides, the existence of which cannot be proven by other means. However, this method cannot reveal all the domains. In this paper we calculate the limits of the HREM possibilities and expound a method to obtain some statistical information on the observed sample.