Competing two-phase coexistence in doped manganites: Direct observations byin situLorentz electron microscopy

2010 ◽  
Vol 82 (22) ◽  
Author(s):  
J. Q. He ◽  
V. V. Volkov ◽  
T. Asaka ◽  
S. Chaudhuri ◽  
R. C. Budhani ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Phase Coexistence ◽  
Two Phase ◽  
Direct Observations ◽  
Doped Manganites

Tunable two-phase coexistence in half-doped manganites

Pramana ◽  
2008 ◽  
Vol 70 (2) ◽  
pp. 193-199 ◽  
Author(s):  
P. Chaddah ◽  
A. Banerjee
Keyword(s):  
Phase Coexistence ◽  
Two Phase ◽  
Doped Manganites

Using crystallographic symmetry in diffraction and contrast analysis

1989 ◽  
Vol 47 ◽  
pp. 504-505
Author(s):  
U. Dahmen ◽  
K.H. Westmacott
Keyword(s):  
Electron Microscopy ◽  
High Symmetry ◽  
Two Phase ◽  
Tem Analysis ◽  
Crystallographic Symmetry ◽  
The Matrix ◽  
Contrast Analysis ◽  
Practical Tool ◽  
Convergent Beam ◽  
Beam Diffraction

Despite the increased use of convergent beam diffraction, symmetry concepts in their more general form are not commonly applied as a practical tool in electron microscopy. Crystal symmetry provides an abundance of information that can be used to facilitate and improve the TEM analysis of crystalline solids. This paper draws attention to some aspects of symmetry that can be put to practical use in the analysis of structures and morphologies of two-phase materials.It has been shown that the symmetry of the matrix that relates different variants of a precipitate can be used to determine the axis of needle- or lath-shaped precipitates or the habit plane of plate-shaped precipitates. By tilting to a special high symmetry orientation of the matrix and by measuring angles between symmetry-related variants of the precipitate it is possible to find their habit from a single micrograph.

scholarly journals Revisiting the Bøggild Intergrowth in Iridescent Labradorite Feldspars: Ordering, Kinetics, and Phase Equilibria

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 727
Author(s):  
Shiyun Jin ◽  
Huifang Xu ◽  
Seungyeol Lee
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Atom Probe ◽  
Phase Region ◽  
Two Phase ◽  
Subsolidus Phase ◽  
Plagioclase Feldspar ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission

The enigmatic Bøggild intergrowth in iridescent labradorite crystals was revisited in light of recent work on the incommensurately modulated structures in the intermediated plagioclase. Five igneous samples and one metamorphic labradorite sample with various compositions and lamellar thicknesses were studied in this paper. The lamellar textures were characterized with conventional transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). The compositions of individual lamellae were analyzed with high-resolution energy-dispersive X-ray spectroscopy (EDS) mapping and atom probe tomography (APT). The average structure states of the studied samples were also compared with single-crystal X-ray diffraction data (SC-XRD). The Na-rich lamellae have a composition of An44–48, and the Ca-rich lamellae range from An56 to An63. Significant differences between the lamellar compositions of different samples were observed. The compositions of the Bøggild intergrowth do not only depend on the bulk compositions, but also on the thermal history of the host rock. The implications on the subsolidus phase relationships of the plagioclase feldspar solid solution are discussed. The results cannot be explained by a regular symmetrical solvus such as the Bøggild gap, but they support an inclined two-phase region that closes at low temperature.

Investigation of low- and high-resistance Ni–Ge–Au ohmic contacts to n+ GaAs using electron microbeam and surface analytical techniques

1996 ◽  
Vol 11 (5) ◽  
pp. 1244-1254 ◽  
Author(s):  
Nancy E. Lumpkin ◽  
Gregory R. Lumpkin ◽  
K. S. A. Butcher
Keyword(s):  
Electron Microscopy ◽  
Ohmic Contacts ◽  
Analytical Electron Microscopy ◽  
Depth Profiling ◽  
Analytical Techniques ◽  
Two Phase ◽  
Low Resistance ◽  
Fine Grained ◽  
Multiphase Microstructure ◽  
Transmission Electron

A process for the formation of low-resistance Ni–Ge–Au ohmic contacts to n+ GaAs has been refined using multivariable screening and response surface experiments. Samples from the refined, low-resistance process (which measure 0.05 ± 0.02 Ω · mm) and the unrefined, higher resistance process (0.17 ± 0.02 Ω · mm) were characterized using analytical electron microscopy (AEM), transmission electron microscopy (TEM), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), and x-ray photoemission spectroscopy (XPS) depth profiling methods. This approach was used to identify microstructural differences and compare them with electrical resistance measurements. Analytical results of the unrefined ohmic process sample reveal a heterogeneous, multiphase microstructure with a rough alloy-GaAs interface. The sample from the refined ohmic process exhibits an alloy which is homogeneous, smooth, and has a fine-grained microstructure with two uniformly distributed phases. XPS analysis for the refined ohmic process sample indicates that the Ge content is relatively depleted in the alloy (relative to the deposited Ge amount) and enriched in the GaAs. This is not evidenced in the unrefined ohmic process sample. Our data lead us to conclude that a smooth, uniform, two-phase microstructure, coupled with a shift in Ge content from the post-alloy metal to the GaAs, is important in forming low-resistance ohmic contacts.

scholarly journals Влияние температуры деформации в камере Бриджмена на особенности формирования дефектной структуры технически чистого титана

2018 ◽  
Vol 44 (20) ◽  
pp. 70
Author(s):  
Н.А. Шурыгина ◽  
А.М. Глезер ◽  
Д.Л. Дьяконов ◽  
А.А. Томчук ◽  
А.Г. Кадомцев ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Defect Structures ◽  
Cryogenic Temperatures ◽  
Two Phase ◽  
Α Phase ◽  
Electron Microscopy Data ◽  
Phase Mixture ◽  
Microscopy Data

AbstractTransmission electron microscopy data showed evidence of the formation of structural regions corresponding to deformation (dislocated) fragments and dynamically recrystallized grains in α-phase titanium upon torsion at high hydrostatic pressure at room and cryogenic temperatures. It is shown that the previously proposed “two-phase mixture” model is applicable to description of these defect structures.

Evaluation of Three Different Cleaners Recommended for Ultrafiltration Systems by Direct Observations of Commercial-Scale Spiral-Wound Ultrafiltration Membranes1

1988 ◽  
Vol 51 (2) ◽  
pp. 89-104 ◽  
Author(s):  
K. E. SMITH ◽  
R. L. BRADLEY
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Visual Inspection ◽  
Membrane Materials ◽  
Direct Observations ◽  
Commercial Scale ◽  
Sweet Whey ◽  
Scanning Electron ◽  
Polysulfone Membranes ◽  
Spiral Wound

Efficacy of cleaners designed for use with ultrafiltration systems was determined by microbiological evaluation and through visual inspection using scanning electron microscopy. The ultrafiltration system containing two commercial-scale, polysulfone membranes was soiled with sweet whey (40°C) then rinsed with water and membranes were removed. One half of each membrane was soaked for 2 h at 38°C in one of the following solutions: control (no soaking), acid cleaner (pH 2.5), enzyme-based cleaner (pH 11.5) and chlorinated alkaline cleaner (pH 11.5). The membranes were repositioned in the ultrafiltration unit, rinsed with water, then removed and unwound for analysis. Sections of membrane, retentate spacer and permeate mesh were aseptically removed for enumeration of microorganisms remaining and for examination by scanning electron microscopy. Membranes cleaned with chlorinated alkaline cleaner averaged 2 × 103 CFU/50 cm2, enzyme-based cleaner 6 × 106/CFU, acid anionic cleaner 1 × 107 CFU and the control 5 × 107CFU. Scanning electron microscopy found soil and microorganisms present on all membrane materials exposed to all three cleaners.

scholarly journals Two-phase behavior in strained thin films of hole-doped manganites

2000 ◽  
Vol 61 (14) ◽  
pp. 9665-9668 ◽  
Author(s):  
Amlan Biswas ◽  
M. Rajeswari ◽  
R. C. Srivastava ◽  
Y. H. Li ◽  
T. Venkatesan ◽  
...  
Keyword(s):  
Thin Films ◽  
Phase Behavior ◽  
Two Phase ◽  
Doped Manganites
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