scholarly journals STUDY OF INTERSTITIAL ATOMS AND VACANCIES IN IRRADIATED CRYSTALS USING X- RAY MEASURED LATTICE PARAMETER TOGETHER WITH DENSITY MEASUREMENTS

1954 ◽  
Author(s):  
J Sampson ◽  
C Tucker, Jr
Keyword(s):  
Lattice Parameter ◽  
Density Measurements ◽  
X Ray ◽  
Interstitial Atoms ◽  
Measured Lattice Parameter

The microstructure and stoichiometry of pyrite FeS2−x

1992 ◽  
Vol 7 (7) ◽  
pp. 1829-1838 ◽  
Author(s):  
S. Fiechter ◽  
M. Birkholz ◽  
A. Hartmann ◽  
P. Dulski ◽  
M. Giersig ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Lattice Parameter ◽  
Population Parameter ◽  
Microscope Examination ◽  
Density Measurements ◽  
X Ray ◽  
Transmission Electron ◽  
Structural Nature ◽  
Synthetic Crystals

Both natural and synthetic crystals of pyrite, FeS2−x, have been analyzed chemically and examined structurally by transmission electron microscopy and x-ray powder diffraction. Chemical analysis and density measurements have shown the synthetic crystals, grown at 850 K, are frequently deficient in sulfur, with a composition of FeS2−x with x ⋚ 0.15. From a refinement of the pyrite structure using the integral intensities of the x-ray powder pattern, a variation in the sulfur population parameter was obtained ranging from 0.87(2) to 1.03(3). A correlation according to Vegard's rule between the population factor and the lattice parameter a0 has been proven. Transmission electron microscope examination revealed that the crystals did not contain a significant population of disorder defects which may account for this apparent sulfur deficit. Therefore the nonstoichiometry in pyrite has to be interpreted in terms of S vacancies which can be understood as the tendency of the material to reduce the high anion content in the unit cell. The structural nature of nonstoichiometric pyrite is discussed in relationship to other related disulfides.

Characterization of the Aurivillius Type PbBi4Ti4O15 Piezoelectric Ceramic Doped with Eu3+

2006 ◽  
Vol 45 ◽  
pp. 2483-2488
Author(s):  
L. Pablos ◽  
Maria Elena Villafuerte-Castrejón ◽  
A. Ibarra-Palos ◽  
J. Ocotlán-Flores ◽  
R. Sato ◽  
...  
Keyword(s):  
Piezoelectric Ceramic ◽  
Solubility Limit ◽  
Lattice Parameter ◽  
Layered Oxides ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Density Measurements ◽  
X Ray ◽  
Wide Range

PbBi4Ti4O15 belongs to the bismuth oxide layers family discovered by Aurivillius more than 50 years ago. In the last few years, there has been considerable interest in layered oxides exhibiting ferroelectric, piezoelectric and other related properties due to their wide range of application in technical devices. In the present work the PbBi4Ti4O15 solid solution formed with Eu3+ was synthesized by coprecipitation method and solubility limit was found. All compounds were characterized by scanning electron microscopy, density measurements and X-ray diffraction. The variation of lattice parameter with the Eu3+ concentration was obtained. Raman spectroscopy was carried out in order to determine the Eu3+ site in the lattice. Thermal analysis (thermogravimetry and differencial scanning calorimetry) results are also presented.

scholarly journals Growth of sillenite Bi12FeO20 single crystals: structural, thermal, optical, photocatalytic features and first principle calculations

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Durga Sankar Vavilapalli ◽  
Ambrose A. Melvin ◽  
F. Bellarmine ◽  
Ramanjaneyulu Mannam ◽  
Srihari Velaga ◽  
...  
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Photoelectron Spectroscopy ◽  
Diffraction Method ◽  
Lattice Parameter ◽  
First Principle ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Principle Calculations ◽  
Photodegradation Efficiency

AbstractIdeal sillenite type Bi12FeO20 (BFO) micron sized single crystals have been successfully grown via inexpensive hydrothermal method. The refined single crystal X-ray diffraction data reveals cubic Bi12FeO20 structure with single crystal parameters. Occurrence of rare Fe4+ state is identified via X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS). The lattice parameter (a) and corresponding molar volume (Vm) of Bi12FeO20 have been measured in the temperature range of 30–700 °C by the X-ray diffraction method. The thermal expansion coefficient (α) 3.93 × 10–5 K−1 was calculated from the measured values of the parameters. Electronic structure and density of states are investigated by first principle calculations. Photoelectrochemical measurements on single crystals with bandgap of 2 eV reveal significant photo response. The photoactivity of as grown crystals were further investigated by degrading organic effluents such as Methylene blue (MB) and Congo red (CR) under natural sunlight. BFO showed photodegradation efficiency about 74.23% and 32.10% for degrading MB and CR respectively. Interesting morphology and microstructure of pointed spearhead like BFO crystals provide a new insight in designing and synthesizing multifunctional single crystals.

scholarly journals Measurements by x-ray diffraction of the temperature dependence of lattice parameter and crystallite size for isostatically-pressed graphite

Carbon Trends ◽  
2021 ◽  
pp. 100071
Author(s):  
Keith R. Hallam ◽  
James Edward Darnbrough ◽  
Charilaos Paraskevoulakos ◽  
Peter J. Heard ◽  
T. James Marrow ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Crystallite Size ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
X Ray

Problems Associated with Kα Doublet in Residual Stress Measurements

1979 ◽  
Vol 23 ◽  
pp. 333-339
Author(s):  
S. K. Gupta ◽  
B. D. Cullity
Keyword(s):  
Residual Stress ◽  
Silicon Powder ◽  
Lattice Parameter ◽  
Diffraction Peak ◽  
Parameter Determination ◽  
X Ray Diffraction ◽  
X Ray ◽  
Analysis Techniques ◽  
The Difference ◽  
Similar Accuracy

Since the measurement of residual stress by X-ray diffraction techniques is dependent on the difference in angle of a diffraction peak maximum when the sample is examined consecutively with its surface at two different angles to the diffracting planes, it is important that these diffraction angles be obtained precisely, preferably with an accuracy of ± 0.01 deg. 2θ. Similar accuracy is desired in precise lattice parameter determination. In such measurements, it is imperative that the diffractometer be well-aligned. It is in the context of diffractometer alignment with the aid of a silicon powder standard free of residual stress that the diffraction peak analysis techniques described here have been developed, preparatory to residual stress determinations.

scholarly journals MOVPE Growth of Quaternary (Al,Ga,In)N for UV Optoelectronics

2000 ◽  
Vol 5 (S1) ◽  
pp. 412-424
Author(s):  
Jung Han ◽  
Jeffrey J. Figiel ◽  
Gary A. Petersen ◽  
Samuel M. Myers ◽  
Mary H. Crawford ◽  
...  
Keyword(s):  
Room Temperature ◽  
Rutherford Backscattering Spectrometry ◽  
Optoelectronic Devices ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
X Ray ◽  
Peak Energy ◽  
Movpe Growth ◽  
Pl Emission

We report the growth and characterization of quaternary AlGaInN. A combination of photoluminescence (PL), high-resolution x-ray diffraction (XRD), and Rutherford backscattering spectrometry (RBS) characterizations enables us to explore the contours of constant- PL peak energy and lattice parameter as functions of the quaternary compositions. The observation of room temperature PL emission at 351nm (with 20% Al and 5% In) renders initial evidence that the quaternary could be used to provide confinement for GaInN (and possibly GaN). AlGaInN/GaInN MQW heterostructures have been grown; both XRD and PL measurements suggest the possibility of incorporating this quaternary into optoelectronic devices.

EFFECTS OF A PARTIAL SUBSTITUTION OF Cu ELEMENTS BY Nb ELEMENTS IN YBaCuO SYSTEM

1990 ◽  
Vol 04 (12) ◽  
pp. 823-830 ◽  
Author(s):  
S. HIGO ◽  
Y. HAKURAKU ◽  
T. OGUSHI ◽  
I. KAWANO ◽  
Y. ISHIKAWA
Keyword(s):  
Solid State Reaction Method ◽  
Lattice Parameter ◽  
Partial Substitution ◽  
Maximum Temperature ◽  
X Ray ◽  
Cubic Lattice ◽  
Nb Content ◽  
Molecular Ratios ◽  
Diffraction Patterns ◽  
Two Phases

Samples of the YBaCuNbO system with different molecular ratios of YBa 2 NbO y to YBa 2 Cu 3 O 7−d, were prepared in air by the solid-state reaction method. The X-ray powder diffraction patterns showed that the sample was composed of two phases, one corresponding to the YBa 2 Cu 3 O 7−d phase and the other to the YBa 2 NbO y phase with a cubic lattice parameter of 8.425 Å to 8.436 Å depending on the Nb content. The superconducting zero resistivity temperature, T c 0, of the YBaCuNbO system increased with the increase of the molecular ratios, from 91.2 K up to a maximum temperature of 92.8 K, and then, by a further increase in the molecular ratio, the T c 0 was drastically reduced with a gradient of −1.94 K /%x.

Annealing Effects on the Physical and Magnetic Properties of Tb1.5Y1.5Fe5O12 Films Nanoparticles Prepared by Sol-Gel Method

2013 ◽  
Vol 756 ◽  
pp. 91-98 ◽  
Author(s):  
Ftema W. Aldbea ◽  
Noor Bahyah Ibrahim ◽  
Mustafa Hj. Abdullah
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Annealing Temperature ◽  
Quartz Substrate ◽  
Sol Gel ◽  
Lattice Parameter ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Iron Garnet

Terbium –substituted yttrium iron garnet (Tb1.5Y1.5Fe5O12) films nanoparticles were successfully prepared by a sol-gel method. The films were deposited on the quartz substrate using spin coating technique. To study effect of annealing temperature, the annealing process was executed at 700, 800 and 900 °C in air for 2 hours. The X-ray diffraction (XRD) proved that the pure phase of garnet structure was detected for the film annealed at 900 °C. The lattice parameter increased with the increment of annealing temperature and the highest value of 12.35 Å was obtained at 900 °C. Field Emission Scanning Electron Microscope (FE-SEM) results showed that the particle size increased from 43nm to 56nm as annealing temperature increased from 700 to 900°C. The film’s thickness also affected by increasing of annealing temperature and become thin at 900 °C due to densification process occurred at high annealing temperature. The elemental compositions of the Tb1.5Y1.5Fe5O12 film were detected using an Energy Dispersive X-raySpectroscopy (EDX). Magnetic properties at room temperature were measured using a Vibrating Sample Magnetometer (VSM).The saturation magnetization Ms increased with the annealingtemperature and showed a high value of 104emu/cm3, but the coercivity Hc of the film was decreased due to the increment of the particle size. Normal 0 21 false false false MS X-NONE X-NONE MicrosoftInternetExplorer4 Terbium –substituted yttrium iron garnet (Tb1.5Y1.5Fe5O12) films nanoparticles were successfully prepared by a sol-gel method. The films were deposited on the quartz substrate using spin coating technique. To study effect of annealing temperature, the annealing process was executed at 700, 800 and 900°C in air for 2 hours. The X-ray diffraction (XRD) proved that the pure phase of garnet structure was detected for the film annealed at 900 °C. The lattice parameter increased with the increment of annealing temperature and the highest value of 12.35 Å was obtained at 900 °C. Field Emission Scanning Electron Microscope (FE-SEM) results showed that the particle size increased from 43nm to 56nm as annealing temperature increased from 700 to 900 °C. The film’s thickness also affected by increasing of annealing temperature and become thin at 900 °C due to densification process occurred at high annealing temperature. The elemental compositions of the Tb1.5Y1.5Fe5O12 film were detected using an Energy Dispersive X-ray Spectroscopy (EDX). Magnetic properties at room temperature were measured using a Vibrating Sample Magnetometer (VSM).The saturation magnetization Ms increased with the annealing temperature and showed a high value of 104emu/cm3, but the coercivity Hc of the film was decreased due to the increment of the particle size. st1\:*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

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