SAED pattern

Figure 1. SAED patterns taken from as-grown (a) Ti-S4 at.%Al, (b) 71-56 at.%Al and (c) 71-S8at.%Al single ciystals along [001],...

Figure I HRTEM images of the (a) 14M and (b) Llo martensite in Ni-Al including the corresponding SAED patterns.

Figure 10(a) shows a TEM image of a sample containing Co and Ni in the ratio 4-1 (Co4Nil) whereas Figure 10(b) is a TEM image of the ColNil sample (implanted at a total fluence 40 x 10 ions/cm ) the SAED pattern for ColNil sample exhibits a single alloy fc.c. phase with lattice parameter a = 0.3533(12) nm, whereas, when the... 

The unit cell and the Bravais lattice type for IM-5 were obtained from tilt series of SAED patterns such as that shown in Figure 2 (a = 14.3 A, b = 57.4 A, c - 20.1 A with... 

C-centering). Its Laue class was determined to be mmm since the SAED patterns show mmm symmetry. Thus, the IM-5 structure is C-centered orthorhombic. 

Figure 3. Low-magnification TEM images and the corresponding SAED patterns of the nanoplates with the [311] zone axis of a-Mn203.

Figure 4. TEM images (a) low magnification, (b) SAED pattern of (a) along the [310] direction, (c) high resolution with the Fourier transform inserted.

The transmission electron microscopy (TEM) and correlated electron diffraction patterns of quenched QAB2-4 alloy is shown in Figure 2. When annealed at 773K, by selected-area electron diffraction (SAED) patterns at transmission electron microscopy appears as a bright continuous ring, indicating an amorphous phase. 

Figure 2. Examples of two-beam (a, b), multi-beam (c) and zone axis (d) SAED patterns.

Nevertheless, this technique has a main disadvantage the minimum size of the diffracted area, which is selected by means of the selected-area aperture, is about 500 nm. It becomes difficult to prevent some thickness variations and/or some orientation variations in the diffracted area. The SAED patterns are, in fact, average patterns and the diffracted intensities can be strongly affected. For that reason, it is recommended to use Microdiffraction or CBED because the diffracted area is directly defined by the incident beam and can reach a few nanometers with recent microscopes. 

Figure 1. Effect of elliptical distortion on the resolution of the measured SAED pattern.

HREM), TEM results of aerinite are compared with X-ray and synchrotron powder diffraction data. Six selected area electron diffraction (SAED) patterns and two HREM images from Pb5MoOg single crystals are used to solve their structure. The unit cell parameters of these crystals confirm the known powder diffraction data. 

The SAED patterns consist of an intense base set of a - PbO subcell reflections and weak superstructure reflections hV4, kV3, T/2 referring to the a - PbO cell due to a modulation of the structure. To determine the Pb and Mo positions in PbsMoOg on the base of the relative intensities of the SAED reflections a multislice dynamic calculation [12] was performed. The calculations were performed separately for each of the 6 experimental microdiffraction patterns. The thickness of the specimen was determined independently for each of the patterns. The performed procedure is close to the published idea by Bing - Dong et al. [13]. 

The electron dose needed for complete disappearance of all crystalline reflections in the SAED pattern is termed the total end-point dose (TEPD),... 

Depending on purposes, a plastic film under the vapor-deposited C is dissolved away with a solvent. By this method, a very thin C support-film of smaller than lOnm in thickness can be made easily. An aluminum (Al) support-film can be made similarly, by vapor-deposition of Al onto a plastic film put on a grid and then by dissolving away the plastic film. The reflection rings from the Al support-film can be used as an internal reference to calibrate the camera length of SAED pattern, and this support film does give no amorphous halo. When an ultra-thin C support-film (less than 5nm in thickness) is desired, a microgrid (MG see Section 3.1.2) should be used on which an ultra-thin film made by indirect vapor-deposition of C has been put in advance. 

On the basis of the model (Case-1), diffraction intensity from an infinite 2-dimensional crystal was mathematically formulated by incorporating the probability, p, of occurrence of a stacking fault (-AA- or -BB- ) in the crystal [30-32], The result clearly showed that the SAED pattern is well reproduced by this formulation with p<0.5. 

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