Phase Microidentification from Selected Area Electron Diffraction (SAED) and Energy Dispersive Spectroscopy (EDS) Data

1991 ◽  
Vol 35 (A) ◽  
pp. 687-691 ◽  
Author(s):  
Josef Macicek
Keyword(s):  
Electron Diffraction ◽  
Energy Dispersive Spectroscopy ◽  
Reciprocal Lattice ◽  
Energy Dispersive ◽  
Phase Identification ◽  
Two Dimensional ◽  
Selected Area Electron Diffraction ◽  
Elemental Data

AbstractTwo-dimensional geometry information contained in SAED spot patterns augmented with EDS elemental data is employed in a computerized phase identification of microcrystalline particles. The initial chemistry screening of a laboratory managed database using the 'bitmap' concept is followed by a geometry search/match treating of the spot patterns as planar sections through the reciprocal lattice of a candidate phase. The identification is selective, fast, and yields to a complete automatization,

Fine Structure in the Selected Area Electron Diffraction Patterns of Beidellite

1975 ◽  
Vol 33 ◽  
pp. 72-73
Author(s):  
N. Güven ◽  
R.W. Pease
Keyword(s):  
Fine Structure ◽  
Electron Diffraction ◽  
Reciprocal Lattice ◽  
Linear Chain ◽  
Lattice Points ◽  
Selected Area Electron Diffraction ◽  
General Terms ◽  
Regular Network ◽  
Diffraction Patterns ◽  
Pass Through

Selected area electron diffraction (SAD) patterns of beidellite exhibit fine structure in the form of nonradial streaks and extra spots between the normal Laue spots. The streaks form a regular network as shown in Figure 1A andvery clearly after a long exposure, in Fig. IB. These streaks do not pass through the origin and they are not symmetrical with respect to the reciprocal lattice points. Therefore they cannot be caused by finite crystallite size. The distribution of the streaks suggests a strong anisotropy in the beidellite structure as they are restricted to the directions parallel to [11], [11], and [02]. However, there are no streaks along the actual [11], [11] and [02] directions. In general terms, these linear streaks are explained by the presence of ‘continuous sheets’ or ‘walls’ of intensity in reciprocal space. These intensity 'walls' are associated with a linear chain of scatterers in the crystal in the direction perpendicular to the intensity sheets. Such linear scatterers may be produced by small shifts of certain atoms due to thermal motion, isomorphic substitutions, distortions, or other lattice imperfections.

On-line diffraction pattern analysis and phase identification using a JEM 2000FX AEM with a macintosh-based program

1994 ◽  
Vol 52 ◽  
pp. 1006-1007
Author(s):  
C. R. Hills ◽  
G. A. Poulter
Keyword(s):  
Electron Diffraction ◽  
Diffraction Pattern ◽  
Real Time ◽  
Pattern Analysis ◽  
Reciprocal Lattice ◽  
Computer Software ◽  
Crystallographic Analysis ◽  
Lattice Points ◽  
Phase Identification ◽  
Reciprocal Lattice Point

A number of computer programs have been written to aid in the indexing of transmission electron diffraction pattcrns. These programs are useful for determining crystallographic orientation and for phase identification and often simplify the analysis of complex patterns. Over the last few years there has been a trend toward automated electron microscopy. It is natural to extend this automation to real time diffraction pattern analysis and phase identification using A/D data acquisition boards and computer software to interface the modern AEM with an electron diffraction database (EDD). This paper describes a real-time Macintosh-based system (hardware and software) for automated electron diffraction pattern analysis and phase identification developed for the JEM 2000FX AEM. Crystallographic analysis with this system is attractive because of the rapid analysis time, ease of implementation, and it is inexpensive compared to buying a digitizing board and video system.Computer-aided diffraction pattern-indexing programs typically require the user to input reciprocal lattice point spacings (r-spacings) and the interplanar angle measurements for at least three non-colinear lattice points in the pattern. It is also necessary to know the crystal structure and lattice constants of the sample.

scholarly journals Phase Identification by Selected Area Electron Diffraction

2003 ◽  
Vol 9 (S02) ◽  
pp. 862-863
Author(s):  
Shirley Turner ◽  
Vicky L. Karen ◽  
David S. Bright
Keyword(s):  
Electron Diffraction ◽  
Phase Identification ◽  
Selected Area Electron Diffraction

Structural effect of the SC-AF transition in BSCYCO system

1992 ◽  
Vol 50 (1) ◽  
pp. 84-85
Author(s):  
Shulin Wen ◽  
Chenyu Song ◽  
J.A. Eades
Keyword(s):  
Electron Diffraction ◽  
Structural Transformation ◽  
Energy Dispersive Spectroscopy ◽  
Hole Concentration ◽  
Analytical Data ◽  
Structural Effect ◽  
Energy Dispersive ◽  
X Ray Diffraction ◽  
Sharp Drop ◽  
X Ray

The transition between the SC (superconductor) and the AF (antiferromagnetic semiconductor) has been investigated in the BSCYCO (Bi2Sr2Ca1-xYxCu2O8+Y) system. During the investigation a tetragonal(T)-orthorhombic(O) structural transformation accompanied by a sharp drop in Tc around at Xc=0.4 has been observed.Some of previous studies on BSCYCO revealed the transition from the SC to the AF around at x=0.5, and interpreted it as a result of a decreasing hole concentration, We have also studied the SC-AF transition of BSCYCO with analytical data combination from not only Tc measurements, but also X-ray diffraction, electron diffraction and energy dispersive spectroscopy (EDS) results. We found that a structural transformation from the tetragonal(T) to the orthorhombic(O) system would be mainly responsible for the SC-AF transition.

Continuous transformation of decagonal quasicrystal to a related crystalline phase

1990 ◽  
Vol 48 (4) ◽  
pp. 132-133
Author(s):  
K.H. Kuo ◽  
H. Zhang
Keyword(s):  
Electron Diffraction ◽  
Rotation Axis ◽  
Orthorhombic Phase ◽  
Structural Similarity ◽  
Two Dimensional ◽  
Continuous Transformation ◽  
Decagonal Quasicrystal ◽  
Decagonal Phase ◽  
Selected Area Electron Diffraction ◽  
Rapidly Solidified

Decagonal quasicrystal is a two-dimensional one with a periodicity of about 1.2 or 1.6 nm along its tenfold rotation axis. It is known to exist in rapidly solidified Al-rich Al-Mn-Si and Al-Cr-Si alloys, sometimes coexisting with the bcc α-AlMnSi or cubic Al13Cr4Si4 phase. Both these two crystalline phases are known to have many icosahedral units in them. The structural similarity between the decagonal phase and the related bcc α-AlMnSi has been studied extensively lately.However, recently we have found a new base-centered orthorhombic phase with a=1.24, b=3.79, and c=1.23 nm coexisting with the decagonal phase to these alloys. Moreover, evidence of a continuous transformation from the latter to the former has been found by selected area electron diffraction. Fig. la is the tenfold electron diffraction pattern (EDP) of the decagonal quasicrystal with strong spots forming a series of concentric decagons. However, in the region close to the boundary to the crystal, the circle on which the inner 10 strong spots lie becomes an ellipse with its long axis in the arrowed direction (Fig. 1b). The closer to the boundary, the more the distortion of this decagon (Fig. 1c) and finally the EDP changes almost to a 2D crossgrid pattern of a base-centered crystal (a reciprocal unit cell is outlined in Fig. 1d).

Orientation relationships between TiB (B27), B2, and Ti3Al phases

2009 ◽  
Vol 24 (5) ◽  
pp. 1688-1692 ◽  
Author(s):  
C.L. Chen ◽  
W. Lu ◽  
L.L. He ◽  
H.Q. Ye
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Diffraction ◽  
Orientation Relationship ◽  
Reciprocal Lattice ◽  
Lattice Points ◽  
Orientation Relationships ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Electron Diffraction Technique

The orientation relationships among TiB (B27), B2, and Ti3Al phases have been investigated by transmission electron microscopy. By using the composite selected-area electron diffraction technique, the orientation relationship between TiB (B27) and B2 was determined to be [100]TiB[001]B2, (001)TiB(010)B2; and that between TiB (B27) and Ti3Al was . These orientation relationships have been predicted precisely by the method of coincidence of reciprocal lattice points.

scholarly journals Unit Cell Determination of New Minerals by Using Electron Diffraction

2014 ◽  
Vol 70 (a1) ◽  
pp. C1098-C1098
Author(s):  
Galiya Bekenova
Keyword(s):  
Electron Beam ◽  
Electron Diffraction ◽  
Diffraction Pattern ◽  
Electron Diffraction Pattern ◽  
Reciprocal Lattice ◽  
Fine Powder ◽  
Selected Area Electron Diffraction ◽  
Ewald Sphere ◽  
Type Pattern ◽  
Diffraction Patterns

Many new minerals recently discovered in Kazakhstan had platy (niksergievite), fiber (kazakhstanite) or fine powder (mitryaevaite) structural appearance. In monoclinic minerals with perfect or good (001) cleavage, d100 i d010-spacings in the hk0 zone could be measured on selected area electron-diffraction pattern from monocrystal tilted the way that axis c is parallel to the electron beam direction. This method was used for measuring d-spacings in new minerals such as kazakhstanite, niksergievite as well as in new discovered micas – sokolovaite and orlovite. In minerals with triclinic structure (mitryaevaite) the same method was used to determine d100, d010 as well as γ=1800-γ* (γ* is an angle between reciprocal lattice axes a* and b*). hk0-indices of each ring were defined by comparison of the normal texture (ring type) pattern and selected area pattern. For example, hk0-indices for triclinic cell of mitryaevaite were (010), (100), (-110), (110), (020) etc. When specimen with preferred orientation is tilted under angle φ toward electron beam, an "oblique texture" electron-diffraction pattern is obtained. Arcs of the ellipses on such diffraction pattern are formed by intersection of Ewald sphere with ring nodes. The height of the arc's maximum above the tilt axis is calculated by using the following formula: D=hp+ks+lq, where p, s, q are measured on the diffraction pattern [1-3]. For example, on "oblique texture" electron-diffraction pattern from vanalite with perfect (010) cleavage, arcs are merged with layer lines that intersect the ellipses and D=ks. Allocation of indices on texture electron-diffraction patterns from monoclinic niksergievite, sokolovaite and orlovite with perfect (001) cleavage is more difficult. In these cases, D= hp+lq. Heights of the arcs are situated symmetrical in regards to each lq level. With the help of "oblique texture" diffraction patterns stacking polytypes were indicated for such minerals.

Size Tunable Synthesis of Gold Nanoplates by Gamma Irradiation in Presence of Polydiallyldimethylammonium Chloride as the Capping Agent

2013 ◽  
Vol 23 ◽  
pp. 57-65
Author(s):  
San Ju Francis ◽  
J. Nuwad ◽  
Alka Gupta ◽  
J.K. Sainis ◽  
R. Tewari ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Gamma Irradiation ◽  
Single Crystals ◽  
Photoelectron Spectroscopy ◽  
Energy Dispersive ◽  
Capping Agent ◽  
X Ray Diffraction ◽  
X Ray ◽  
Polydiallyldimethylammonium Chloride ◽  
Selected Area Electron Diffraction

A simple gamma irradiation strategy was developed for the synthesis of gold nanoplates by employing polydiallyldimethylammonium chloride (PDDA) as the capping agent. The nanoplates produced had hexagonal, triangular and truncated triangular shapes and the size of the nanoplates could be varied from 500 nm to 5 μm by adjusting the concentration of Au3+ and PDDA in the solution. X-ray diffraction and selected area electron diffraction investigations proved that the nanoplates are single crystals bound by the {111} planes on the top and bottom surfaces. The nanoplates were also characterized by energy dispersive X-ray analysis and X-ray photoelectron spectroscopy.

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