scholarly journals Textures of Phases in Al2O3 - ZrO2 (Y2O3) Eutectic Composites

1995 ◽  
Vol 25 (1) ◽  
pp. 25-32 ◽  
Author(s):  
B. A. Gnesin ◽  
M. Yu. Starostin
Keyword(s):  
Growth Direction ◽  
Preferred Orientation ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
X Ray

Crystallograhic textures of phases in eutectics Al2O3 + ZrO2 (Y2O3) were investigated by means of X-ray diffraction. In all studied eutectic polycrystalls (grown from the melt by EFG technique) a preferred orientation [0001] of Al2O3 along the growth direction in all the samples was revealed for both initial orientations of Al2O3 seeding crystal: <0001> and <1011>. For a cubic ZrO2 there were two types of a preferred orientations: sharp ones, close to <123> with a 6-fold symmetry and more spread <110>. Such a 6-fold symmetry for a cubic phase appears in eutectic due to a joint crystallization.

Preferred Orientation of Cu2O Nano-/Micro-Protrusions Grown by Ar Ion Irradiation

2010 ◽  
Vol 638-642 ◽  
pp. 1784-1789 ◽  
Author(s):  
Shogo Oda ◽  
Hiroyuki Tanaka ◽  
Shunichiro Tanaka
Keyword(s):  
Electron Backscatter Diffraction ◽  
Ion Irradiation ◽  
Incident Angle ◽  
Growth Direction ◽  
Preferred Orientation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Glancing Angle ◽  
Backscatter Diffraction ◽  
Growth Technology

We have developed a bottom-up growth technology for nanostructures from a Cu surface by Ar ion irradiation. Cu2O conical nano-/micro-protrusions have been nucleated and grown from the surface of a preoxidized Cu plate by Ar ion irradiation in low vacuum. In this study, the growth direction or preferred orientation of the protrusions was analysed using glancing angle X-ray diffraction (GAXRD) analysis and an X-ray diffraction pole figure (XRD-PF) measurement. The GAXRD patterns showed that the main phase of the product obtained by Ar irradiation was Cu2O, shown as the highest peak of Cu2O (111), and CuO was additionally formed. The intensity ratio of Cu2O (110) to Cu2O (111) increased as the X-ray incident angle decreased from 10.0 to 0.5 deg, which indicated that the basal plane of the protrusions including the substrate was (110). Additionally, the XRD-PF {011}<001> 3-D plots showed the <110> preferred orientation of the product. These results explain that the growth direction or preferred orientation of the Cu2O protrusions is mainly <110>. The growth direction of the protrusions was separated and confirmed as <110> by checking the electron backscatter diffraction pattern (EBSP) of each protrusion.

scholarly journals Study of the Preferred Orientation of Hydroxyapatite in Ivory from Zimbabwe and Mammoth Ivory from Siberia

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 572
Author(s):  
Xue Ying Sun ◽  
Ming Yue He ◽  
Jin Lin Wu
Keyword(s):  
Growth Direction ◽  
Preferred Orientation ◽  
Crystal Formation ◽  
Orientation Factor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Angle Bisector ◽  
Pole Figures ◽  
First Time ◽  
Insight Into

In this paper, the pole figures plotted from X-ray diffraction data are employed to analyze the orientation of hydroxyapatite in ivory and mammoth ivory for the first time. The results present evidence of the lamellar structure and the hydroxyapatite appeared as tabular. A preferred orientation of hydroxyapatite was revealed in terms of the calculated orientation factor and the characteristics found in the pole figures. The c-axes of hydroxyapatite are mainly oriented along the growth direction. Both a-axes are on the left of the angle bisector of Retzius. Approximately 25–30° separates the a-axes and the angle bisector of Retzius in ivory, whereas the figure is approximately 10–15° in mammoth ivory. Our work is significant in providing more accurate knowledge of the shapes and organizational state of bio-mineral crystals and providing insight into crystal formation and development in bio-mineralization.

scholarly journals Transport and Dielectric Properties of Mechanosynthesized La2/3Cu3Ti4O12 Ceramics

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 313
Author(s):  
Mohamad M. Ahmad ◽  
Hicham Mahfoz Kotb ◽  
Celin Joseph ◽  
Shalendra Kumar ◽  
Adil Alshoaibi
Keyword(s):  
Dielectric Constant ◽  
Sintering Temperature ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Boundary Conductivity ◽  
X Ray ◽  
Giant Dielectric ◽  
Mechanochemical Milling ◽  
Giant Dielectric Constant ◽  
Lower Temperature

La2/3Cu3Ti4O12 (LCTO) powder has been synthesized by the mechanochemical milling technique. The pelletized powder was conventionally sintered for 10 h at a temperature range of 975–1025 °C, which is a lower temperature process compared to the standard solid-state reaction. X-ray diffraction analysis revealed a cubic phase for the current LCTO ceramics. The grain size of the sintered ceramics was found to increase from 1.5 ± 0.5 to 2.3 ± 0.5 μm with an increase in sintering temperature from 975 to 1025 °C. The impedance results show that the grain conductivity is more than three orders of magnitude larger than the grain boundary conductivity for LCTO ceramics. All the samples showed a giant dielectric constant (1.7 × 103–3.4 × 103) and dielectric loss (0.09–0.17) at 300 K and 10 kHz. The giant dielectric constant of the current samples was attributed to the effect of internal barrier layer capacitances due to their electrically inhomogeneous structure.

Stacking Faults in a High Nitrogen Face-Centered-Cubic Phase Formed on Nitrogen-Modified Austenitic Stainless Steel

2008 ◽  
Vol 373-374 ◽  
pp. 318-321
Author(s):  
J. Liang ◽  
M.K. Lei
Keyword(s):  
Stainless Steel ◽  
Plasma Source ◽  
Peak Shift ◽  
Cubic Phase ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
High Nitrogen ◽  
X Ray ◽  
Peak Asymmetry ◽  
Face Centered

Effects of stacking faults in a high nitrogen face-centered-cubic phase (γΝ) formed on plasma source ion nitrided 1Cr18Ni9Ti (18-8 type) austenitic stainless steel on peak shift and peak asymmetry of x-ray diffraction were investigated based on Warren’s theory and Wagner’s method, respectively. The peak shift from peak position of the γΝ phase is ascribed to the deformation faults density α, while the peak asymmetry of the γΝ phase is characterized by deviation of the center of gravity of a peak from the peak maximum (Δ C.G.) due to the twin faults density β. The calculated peak positions of x-ray diffraction patterns are consistent with that measured for plasma source ion nitrided 1Cr18Ni9Ti stainless steel.

A Study on the Growth of Cubic GaN Films Using an AlGaAs Buffer Layer Grown on GaAs (100) by Plasma-Assisted Molecular Beam Epitaxy

2000 ◽  
Vol 639 ◽  
Author(s):  
Ryuhei Kimura ◽  
Kiyoshi Takahashi ◽  
H. T. Grahn
Keyword(s):  
Molecular Beam Epitaxy ◽  
Buffer Layer ◽  
Molecular Beam ◽  
High Energy ◽  
Rf Plasma ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cubic Gan

ABSTRACTAn investigation of the growth mechanism for RF-plasma assisted molecular beam epitaxy of cubic GaN films using a nitrided AlGaAs buffer layer was carried out by in-situ reflection high energy electron diffraction (RHEED) and high resolution X-ray diffraction (HRXRD). It was found that hexagonal GaN nuclei grow on (1, 1, 1) facets during nitridation of the AlGaAs buffer layer, but a highly pure, cubic-phase GaN epilayer was grown on the nitrided AlGaAs buffer layer.

NbN Thin Film of Alternating Textures

2017 ◽  
Vol 898 ◽  
pp. 1431-1437
Author(s):  
Hong Yang Shao ◽  
Kan Zhang ◽  
Yi Dan Zhang ◽  
Mao Wen ◽  
Wei Tao Zheng
Keyword(s):  
Deposition Time ◽  
Peak Position ◽  
Preferred Orientation ◽  
Intrinsic Stress ◽  
Competitive Growth ◽  
X Ray Diffraction ◽  
X Ray ◽  
Orientation Distributions ◽  
Different Thickness ◽  
Deposited Films

The δ-NbN thin films with different thickness have been prepared by reactive magnetron sputtering at different deposition time and exhibited alternating textures between (111) and (200) orientations as a function of thickness. In addition, the grain size, peak position, morphology, residual stress and orientation distributions of the deposited films were explored by X-ray diffraction, low-angel X-ray reflectivity, scanning electron microscopy and surface profiler. The film deposited at 300 s showed a (111) preferred orientation, changing to (200) preferred orientation at 600 s, and exhibited alternating textures between (111) and (200) preferred orientations. With further increasing deposition time, in which (200) peak position and the full width at half maximum of (111) peak also displayed a trend of alternating variation with varying deposition time. The intrinsic stress for δ-NbN films calculated by Stoney equation alternately changed with alternating textures, in which (111) orientation always takes place at relatively high intrinsic stress state and vice versa. Meanwhile, the film with (111) preferred orientation showed higher density than (200) preferred orientation. The film deposited at 4800 s owned a mixed texture of (111) and (200), showing an anisotropy distribution of (111)-oriented and (200)-oriented grains, while film deposited at 7200 s owned a strong (200) texture, displaying an isotropy distribution of (200)-oriented grains. The competitive growth between (111)-oriented and (200)-oriented grains was responsibility for alternating texture.

Template Synthesis of Indium Nanowires Using Anodic Aluminum Oxide Membranes

2008 ◽  
Vol 8 (9) ◽  
pp. 4488-4493 ◽  
Author(s):  
Feng Chen ◽  
Adrian H. Kitai
Keyword(s):  
Aluminum Oxide ◽  
Template Synthesis ◽  
Anodic Aluminum Oxide ◽  
Preferred Orientation ◽  
Hydraulic Pressure ◽  
X Ray Diffraction ◽  
Aao Template ◽  
X Ray ◽  
Anodic Aluminum ◽  
Oxide Membranes

Indium nanowires with diameters approximately 300 nm have been synthesized by a hydraulic pressure technique using anodic aluminum oxide (AAO) templates. The indium melt is injected into the AAO template and solidified to form nanostructures. The nanowires are dense, continuous and uniformly run through the entire ∼60 μm thickness of the AAO template. X-ray diffraction (XRD) reveals that the nanowires are polycrystalline with a preferred orientation. SEM is performed to characterize the morphology of the nanowires.

X-ray diffraction study of oxygen-conducting compoundsLn2Mo2O9(Ln= La, Pr)

2014 ◽  
Vol 70 (4) ◽  
pp. 669-675 ◽  
Author(s):  
Alexander M. Antipin ◽  
Olga A. Alekseeva ◽  
Natalia I. Sorokina ◽  
Alexandra N. Kuskova ◽  
Michail Yu. Presniakov ◽  
...  
Keyword(s):  
Room Temperature ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Ion Migration ◽  
Transmission Microscopy ◽  
Coordination Environment ◽  
X Ray ◽  
Oxygen Ions ◽  
Oxygen Ion ◽  
Oxygen Ion Migration

The La2Mo2O9(LM) and Pr2Mo2O9(PM) single crystals are studied using precision X-ray diffraction and high-resolution transmission microscopy at room temperature. The crystal structures are determined in the space groupP213. La and Pr atoms, as well as Mo1 and O1 atoms, are located in the vicinity of the threefold axes rather than on the axes as in the high-temperature cubic phase. In both structures studied, the O2 and O3 positions are partially occupied. The coexistence of different configurations of the Mo coordination environment facilitates the oxygen-ion migration in the structure. Based on the X-ray data, the activation energies of O atoms are calculated and the migration paths of oxygen ions in the structures are analysed. The conductivity of PM crystals is close to that of LM crystals. The O2 and O3 atoms are the main contributors to the ion conductivity of LM and PM.

scholarly journals Cubic InGaN Grown by MOCVD

1999 ◽  
Vol 4 (S1) ◽  
pp. 239-243
Author(s):  
J.B. Li ◽  
Hui Yang ◽  
L.X. Zheng ◽  
D.P. Xu ◽  
Y.T. Wang
Keyword(s):  
Room Temperature ◽  
Emission Peak ◽  
Buffer Layers ◽  
Cubic Phase ◽  
Yellow Luminescence ◽  
X Ray Diffraction ◽  
High Quality ◽  
X Ray ◽  
Cubic Gan ◽  
Pl Emission

We report on the growth of high-quality cubic phase InGaN on GaAs by MOCVD. The cubic InGaN layers are grown on cubic GaN buffer layers on GaAs (001) substrates. The surface morphology of the films are mirror-like. The cubic nature of the InGaN films is obtained by X-ray diffraction (XRD) measurements. The InGaN layers show strong photoluminescence (PL) at room temperature. Neither emission peak from wurtzite GaN nor yellow luminescence is observed in our films. The highest In content as determined by XRD is about 17% with an PL emission wavelength of 450 nm. The FWHM of the cubic InGaN PL peak are 153 meV and 216 meV for 427 nm and 450 nm emissions, respectively. It is found that the In compositions determined from XRD are not in agreement with those estimated from PL measurements. The reasons for this disagreement are discussed.

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