Characterization of Natural and Synthesized FeTiO3 Crystals With RBS/PIXE/XRD

1997 ◽  
Vol 07 (03n04) ◽  
pp. 265-275
Author(s):  
R. Q. Zhang ◽  
S. Yamamoto ◽  
Z. N. Dai ◽  
K. Narumi ◽  
A. Miyashita ◽  
...  

Natural FeTiO 3 (illuminate) and synthesized FeTiO 3, single crystals were characterized by Rutherford backscattering spectroscopy combined with channeling technique and particle-induced x-ray emission (RBS-C and PIXE). The results obtained by the ion beam analysis were supplemented by the x-ray diffraction analysis to identify the crystallographic phase. Oriented single crystals of synthesized FeTiO 3 were grown under the pressure control of CO 2 and H 2 mixture gas using a single-crystal floating zone technique. The crystal quality of synthesized FeTiO 3 single crystals could be improved by the thermal treatment but the exact pressure control is needed to avoid the precipitation of Fe 2 O 3 even during the annealing procedure. Natural FeTiO 3 contains several kinds of impurities such as Mn , Mg , Na and Si . The synthesized samples contain Al , Si and Na which are around 100 ppm level as impurities. The PBS-C results of the natural sample imply that Mn impurities occupy the Fe sublattice in FeTiO 3 or in mixed phase between ilmenite and hematite.

Crystals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 273
Author(s):  
Pascal Puphal ◽  
Stephan Allenspach ◽  
Christian Rüegg ◽  
Ekaterina Pomjakushina

We present a route to grow single crystals of Ba 0.9 Sr 0.1 CuSi 2 O 6 suitable for inelastic neutron studies via the floating zone technique. Neutron single crystal diffraction was utilized to check their bulk quality and orientation. Finally, the high quality of the grown crystals was proven by X-ray diffraction and magnetic susceptibility.


2021 ◽  
pp. 126152
Author(s):  
P. Aravinth Kumar ◽  
Arun Kumar ◽  
Keshav Kumar ◽  
Pragya Singh ◽  
G. Anandha Babu ◽  
...  

1962 ◽  
Vol 6 ◽  
pp. 158-163
Author(s):  
H. S. Peiser ◽  
E. P. Levine

AbstractLarge single crystals can be examined by conventional X-ray diffraction procedures only at their surface or by destructive sectioning. Within the limitations inherent in polychromatic X-ray photography, high-voltage Laue pictures arc shown to give some information on the internal quality of large crystals.Asterism in conventional Laue photographs is contrasted, with streaks due to geometric effects in Laue patterns of large crystals. Detail within the streaks reveals subgrain structure. A primary extinction effect can be used as striking proof of good crystals being capable of scattering coherently over large distances.


Author(s):  
S.Y. Hwang ◽  
B.G. Seong ◽  
M.C. Kim

Abstract To maintain surface roughness of process rolls in cold rolling steel plants, WC-Co coatings have been known to be effective ones. In this study, a high pressure/high velocity oxygen fuel (HP/HVOF) process was used to obtain WC-Co coatings. To get the best quality of coatings, WC-Co coatings are sprayed with numerous powders made by various processes. These powders include agglomerated sintered powders, fused-crushed powders, extra high carbon WC-Co powders and (W2C, WC)-Co powders. After spraying, properties of coatings such as hardness, wear resistance. X-ray diffraction, and microstructures were analyzed. For coatings produced by agglomerated-sintered powders, hardness of the coating increased as power levels and the number of passes were increased. In case of the coatings produced by fused-crushed powders, a very low deposition rate was obtained due to a low flowablity of the powders. In addition, the WC-Co coatings sprayed with extra carbon content of WC-Co did not show improved hardness and wear resistance. Also, some decomposition of WC was observed in the coating. Finally, the coatings produced by (W2C, WC)-Co powders produced higher hardness and lower wear resistance coating.


Author(s):  
Michael R. Jackson ◽  
Thomas L. Selby

A recombinant metal-dependent phosphatidylinositol-specific phospholipase C (PI-PLC) fromStreptomyces antibioticushas been crystallized by the hanging-drop method with and without heavy metals. The native crystals belonged to the orthorhombic space groupP222, with unit-cell parametersa= 41.26,b= 51.86,c = 154.78 Å. The X-ray diffraction results showed significant differences in the crystal quality of samples soaked with heavy atoms. Additionally, drop pinning, which increases the surface area of the drops, was also used to improve crystal growth and quality. The combination of heavy-metal soaks and drop pinning was found to be critical for producing high-quality crystals that diffracted to 1.23 Å resolution.


1999 ◽  
Vol 4 (S1) ◽  
pp. 429-434 ◽  
Author(s):  
C. H. Wei ◽  
Z. Y. Xie ◽  
J. H. Edgar ◽  
K. C. Zeng ◽  
J. Y. Lin ◽  
...  

Boron was incorporated into GaN in order to determine its limits of solubility, its ability of reducing the lattice constant mismatch with 6H-SiC, as well as its effects on the structural and optical properties of GaN epilayers. BxGa1−xN films were deposited on 6H-SiC (0001) substrates at 950 °C by low pressure MOVPE using diborane, trimethylgallium, and ammonia as precursors. A single phase alloy with x=0.015 was successfully produced at a gas reactant B/Ga ratio of 0.005. Phase separation into pure GaN and BxGa1−xN alloy with x=0.30 was deposited for a B/Ga reactant ratio of 0.01. This is the highest B fraction of the wurtzite structure alloy ever reported. For B/Ga ratio ≥ 0.02, no BxGa1−xN was formed, and the solid solution contained two phases: wurtzite GaN and BN based on the results of Auger and x-ray diffraction. The band edge emission of BxGa1−xN varied from 3.451 eV for x=0 with FWHM of 39.2 meV to 3.465 eV for x=0.015 with FWHM of 35.1 meV. The narrower FWHM indicated that the quality of GaN epilayer was improved with small amount of boron incorporation.


2000 ◽  
Vol 626 ◽  
Author(s):  
Svilen Bobev ◽  
Slavi C. Sevov

ABSTRACTWe have synthesized large single crystals of clathrate-II compounds with frameworks of silicon and germanium by employing mixed alkali metal countercations. The combinations of alkali metals are rationally selected in order to fit the different cages of the clathrate-II structure. This approach leads to the following stoichiometric and fully “stuffed” compounds: Cs8Na16Si136, Cs8Na16Ge136, Rb8Na16Si136 and Rb8Na16Ge136. The structures and the corresponding Si-Si and Ge-Ge distances are elucidated and established with high accuracy from extensive single crystal X-ray diffraction work. The compounds are stoichiometric, metallic, and are very stable at a variety of extreme conditions such as heat, concentrated acids, hydrothermal treatment etc. No evidence was found for vacancies in the silicon and germanium networks or partial occupancies of the alkali metal sites. The stoichiometry of these fully “stuffed” clathrates is consistent with the measured temperature independent Pauli paramagnetism, supported also by the conductivity measurements on single crystals and thermopower measurements on pellets. A new compound with novel clathrate-like structure forms when small and large cations are combined with tin. The new materials, A6Na18Sn46 (A = K, Rb, Cs), are made of clathrate layers and the interlayer space filled with Sn4-tetrahedra and alkali-metal cations. Its formula can be rationalized as A6Na6Sn34 + 3·Na4Sn4 (one clathrate layer and three tin tetrahedra). The compound is stable in air and is being currently tested at other conditions. Detailed measurements of its transport properties are under way.


1998 ◽  
Vol 537 ◽  
Author(s):  
C. H. Wei ◽  
Z. Y. Xie ◽  
J. H. Edgar ◽  
K. C. Zeng ◽  
J. Y. Lin ◽  
...  

AbstractBoron was incorporated into GaN in order to determine its limits of solubility, its ability of reducing the lattice constant mismatch with 6H-SiC, as well as its effects on the structural and optical properties of GaN epilayers. BxGal-xN films were deposited on 6H-SiC (0001) substrates at 950 °C by low pressure MOVPE using diborane, trimethylgallium, and ammonia as precursors. A single phase alloy with x=0.015 was successfully produced at a gas reactant B/Ga ratio of 0.005. Phase separation into pure GaN and BxGal-xN alloy with x=0.30 was deposited for a B/Ga reactant ratio of 0.01. This is the highest B fraction of the wurtzite structure alloy ever reported. For B/Ga ratio ≥ 0.02, no BxGal-xN was formed, and the solid solution contained two phases: wurtzite GaN and BN based on the results of Auger and x-ray diffraction. The band edge emission of BxGal-xN varied from 3.451 eV for x=0 with FWHM of 39.2 meV to 3.465 eV for x=0.015 with FWHM of 35.1 meV. The narrower FWHM indicated that the quality of GaN epilayer was improved with small amount of boron incorporation.


2008 ◽  
Vol 516 (23) ◽  
pp. 8447-8452 ◽  
Author(s):  
A. Redondo-Cubero ◽  
R. Gago ◽  
F. González-Posada ◽  
U. Kreissig ◽  
M.-A. di Forte Poisson ◽  
...  

2012 ◽  
Vol 465 ◽  
pp. 186-191
Author(s):  
Shou Long Gong ◽  
Fang Lin Du

Star-like CuO with submicrometer sizes was fabricated via a simple liquid-phase deposition with the assistant of PVP and Na2MoO4. The as-prepared CuO have been characterized by X-ray diffraction(XRD) and scanning electron microscopy (SEM). The results showed that the as-prepared CuO owned monoclinic structure, the concentrations of PVP, Na2MoO4 and NaOH are very important to the morphology of CuO. The quality of PVP impacts the formation of thin flakes on the skeletons. Meanwhile, the growth of dendritic skeletons was depended on the addition of Na2MoO4, and the effect of NaOH is to control the dimension of CuO structure.


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