Bond length (Ti–O) dependence of nano ATO3-based (A = Pb, Ba, Sr) perovskite structures: Optical investigation in IR range

2018 ◽  
Vol 32 (01) ◽  
pp. 1750356
Author(s):  
Mahdi Ghasemifard ◽  
Misagh Ghamari ◽  
Cengiz Okay
Keyword(s):  
Bond Length ◽  
Complex Refractive Index ◽  
Average Crystallite Size ◽  
Optical Investigation ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
Polyhedral Particles ◽  
Auto Combustion ◽  
Xrd Patterns ◽  
The Impact

In the current study, ABO3 (A = Pb, Ba, Sr and B = Ti) perovskite structures are produced by the auto-combustion route by using citric acid (CA) and nitric acid (NA) as fuel and oxidizer. The X-ray diffraction (XRD) patterns confirmed the perovskite nanostructure with cubic, tetragonal, and rhombohedral for SrTiO3, PbTiO3, and BaTiO3, respectively. Using Scherrer’s equation and XRD pattern, the average crystallite size of the samples were acquired. The effect of Ti–O bond length on the structure of the samples was evaluated. The type of structures obtained depends on Ti–O bond length which is in turn influenced by A[Formula: see text] substitutions. Microstructural studies of nanostructures calcined at 850[Formula: see text]C confirmed the formation of polyhedral particles with a narrow size distribution. The values of optical band gaps were measured and the impact of A[Formula: see text] was discussed. The optical properties such as the complex refractive index and dielectric function were calculated by IR spectroscopy and Kramers–Kronig (K–K) relations. Lead, as the element with the highest density as compared to other elements, changes the optical constants, remarkably due to altering titanium and oxygen distance in TO6 groups.

Effect of Annealing Temperature of CoCr2O4 on Structural and Vibrational Properties

2019 ◽  
Vol 11 (11) ◽  
pp. 1079-1081 ◽  
Author(s):  
Prachi Joshi ◽  
Pallavi Saxena ◽  
M. D. Varshney ◽  
V. N. Rai ◽  
A. Mishra
Keyword(s):  
Calcination Temperature ◽  
Sol Gel ◽  
Average Crystallite Size ◽  
Combustion Method ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
Auto Combustion ◽  
Different Temperatures ◽  
Disorder Effect ◽  
High Calcination Temperature

CoCr2O4 nanoparticles were prepared by low-temperature sol–gel auto combustion method. In this paper, we have investigated the structural behavior of CoCr2O4 nanoparticles annealed at two different temperatures (600 °C and 800 °C). From the X-ray diffraction (XRD) pattern of CoCr2O4, we have found that there is no change in crystalline structure and it was indexed in the cubic spinel structure with space group Fd3m. It was observed that average crystallite size increases with calcination temperature. High calcination temperature reduced the noise level and enhanced the accuracy of calculated parameters. For both the samples of CoCr2O4, we observed Raman scattering modes at around 471, 516, 539, 561, 590, 626 and 688 cm–1. The additional modes in vibrational spectra appear due to the disorder effect.

STRUCTURE AND MAGNETIC PROPERTIES OF MECHANICAL ALLOYED Mn-15at.%Al

2013 ◽  
Vol 12 (01) ◽  
pp. 1350006
Author(s):  
AHMED E. HANNORA ◽  
FARIED F. HANNA ◽  
LOTFY K. MAREI
Keyword(s):  
Thermal Analysis ◽  
Room Temperature ◽  
Average Crystallite Size ◽  
Al Alloy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Milled Sample ◽  
Powder Samples ◽  
Xrd Patterns ◽  
Method Analysis

Mechanical alloying (MA) method has been used to produce nanocrystallite Mn -15at.% Al alloy. X-ray diffraction (XRD) patterns for the as-milled elemental α- Mn and aluminum powder samples show a mixture of α + β- MnAl phases after 20 h of milling and changes to a dominant β- MnAl phase structure after 50 h. An average crystallite size of 40 nm was determined from Hall–Williamson method analysis after 5 h of milling. Moreover, the thermal analysis results using differential thermal analysis (DTA), suggested a possible phase transformation after 20 h of milling. Isothermal treatments are carried in the temperature range of 450°C to 1000°C. Room-temperature vibrating sample magnetometer (VSM) measurements of the hysteretic response revealed that the saturation magnetization Bs and coercivity Hc for 10 h ball milled sample are ~ 2.1 emu/g and ~ 92 Oe, respectively.

scholarly journals FTIR and Optical Properties of NiO Doped Cr2O3 Nanopar-ticles Synthesis by Hydrothermal Method

2018 ◽  
Vol 29 (1) ◽  
pp. 168
Author(s):  
Tunis Balassim Hassan
Keyword(s):  
Optical Band Gap ◽  
Average Crystallite Size ◽  
Structural Behavior ◽  
X Ray Diffraction ◽  
Nanopar Ticles ◽  
Hydrothermal Technique ◽  
X Ray ◽  
Cr2o3 Nanoparticles ◽  
Xrd Patterns ◽  
Scanning Electron

Pure and Nickel oxide doped chromium (III) oxide (Cr2O3) nanoparticals are synthesized by hydrothermal technique. The effect of dopant Ni concentration on the structural behavior of Cr2O3 nanoparticles was examined by X-ray diffraction. The average crystallite size of the synthesized nanoparticles was measured from XRD patterns using Scherrer equation and was decreased from 22nm to 12.9 nm with the increasing Nio concentration in Cr2O3 from (0, 0.01, 0.06, and 0.10). Morphologies and compositional elements of the synthesized nanoparticles were observed by the field emission scanning electron microscopy (FESEM) and energy dispersive X-ray (EDX) spectroscopy, respectively. The optical property of the samples was measured by ultraviolet - visible (UV-Vis.) absorption spectroscopy. The observed optical band gap value ranges from 2.3eV to 2.5eV for Ni doped nanoparticles

Frequency dependence and fuel effect on optical properties of nano TiO2-based structures

2016 ◽  
Vol 30 (18) ◽  
pp. 1650247 ◽  
Author(s):  
Mahdi Ghasemifard ◽  
Misagh Ghamari ◽  
Meysam Iziy
Keyword(s):  
Particle Size ◽  
Optical Properties ◽  
Average Particle Size ◽  
Combustion Method ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Nano Tio2 ◽  
Transmission Electron ◽  
Auto Combustion ◽  
Xrd Patterns

TiO2-(Ti[Formula: see text]Si[Formula: see text]O2 nanopowders (TS-NPs) with average particle size around 90 nm were successfully synthesized by controlled auto-combustion method by using citric acid/nitric acid (AC:NA) and urea/metal cation (U:MC). The structure of powders was studied based on their X-ray diffraction (XRD) patterns. The XRD of TS-NPs shows that rutile and anatase are the main phases of TS-NPs for AC:NA and U:MC, respectively. Particle size and histogram of nanopowders were characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS). Optical properties of TS-NPs were calculated by Fourier transform infrared spectroscopy (FTIR) and Kramers–Kroning (KK) relation. Plasma frequencies of TS-NPs obtained from energy loss functions depend on fuels as a result of changes in crystal structure, particle size distribution, and morphology.

scholarly journals Enhancement in DC Electrical Resistivity and Dielectric Behaviour of Ti4+ Doped CoFe2O4 NP’s for Nanoelectronics Application

2020 ◽  
Vol 9 (6) ◽  
pp. 257-262
Keyword(s):  
Cobalt Ferrite ◽  
Average Crystallite Size ◽  
Information Storage ◽  
Dielectric Behaviour ◽  
X Ray Diffraction ◽  
Dielectric Parameters ◽  
Phase Spinel ◽  
Vibrational Bands ◽  
Ft Ir ◽  
Xrd Patterns

Inverse spinel structured cobalt ferrite is one of the capable nominee for information storage and also in nanoelectronics devices. The present paper reports the rietveld refined structural, elastic, electrical and dielectric behaviour of titanium doped CoFe2O4 NP’s. The synthesis of Co1+xTixFe2-2xO4 (where, 0.0  x  0.5) nanoparticles was performed using self generated combustion technique. The prepared NP’s were characterized by X-ray diffraction technique (XRD) and Fourier transform infrared spectroscopy (FT-IR) technique to analyze the structural and elastic properties. The analysis of XRD patterns confirms the formation of single phase spinel cubic structure of all the prepared samples. The diffractograms obtained at room temperature were used for Rietveld refinement to determine the lattice constant, oxygen position, average crystallite size etc. parameters. The elastic modules were investigated through vibrational bands in FTIR spectra. The band positions in FT-IR spectra confirmed the octahedral [B] and tetrahedral (A) stretching which evident the ferrite skeleton. The plot of DC electrical resitivity with respect to temperature shows the semiconducting behaviour of the nanoparticles. The activation energy determined through resistivity plots, show decreasing nature with incrementing Ti4+ doping in cobalt ferrite. The dielectric parameters decreased exponentially with increasing frequency and with Ti doping.

The structure of zeolite LZ-277

1994 ◽  
Vol 52 ◽  
pp. 784-785
Author(s):  
C. A. Bateman ◽  
R. M. Kirchner
Keyword(s):  
Pore Size ◽  
Diffraction Pattern ◽  
Molecular Sieve ◽  
Unit Cell ◽  
Physical Mixture ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
Space Group ◽  
X Ray ◽  
Xrd Patterns

LZ-277 is a new aluminosilicate molecular sieve. It has an x-ray diffraction (XRD) pattern nearly identical to zeolite phi but with a much smaller pore size. Whether LZ-277 and phi-like materials are intergrowths or a physical mixture of phases has been a matter of debate. The ability to determine the structure of complex zeolites has been enhanced by HREM and, more recently, by the ability to simulate XRD patterns of faulted materials. In this study, the structure of zeolite LZ-277 is reported and confirmed by simulating the XRD pattern of this highly faulted material.The low magnification micrograph shows the faulted and intergrown disc morphology typical of this material (Figure 1). The faulting is most typically twinning on (001), and is shown in the [010] diffraction pattern (Figure 2). The pattern is indexed on an a = 1.38 nm, c = 1.50 nm unit cell and both lattice parameters and systematic absences are consistent with chabazite in space group Rm.

Structural and Transport Properties of La0.85Te0.15MnO3 Manganite and its Composite with Al2O3

2022 ◽  
Vol 1048 ◽  
pp. 110-120
Author(s):  
D.A. Dadhania ◽  
G.D. Jadav ◽  
S.K. Chavda ◽  
J.A. Bhalodia
Keyword(s):  
Secondary Phase ◽  
Peak Position ◽  
Rhombohedral Structure ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Nano Powder ◽  
Auto Combustion ◽  
Combustion Technique

The manganite systems investigated during the present work are pure La0.85Te0.15MnO3 (LTMO) and its composite with 12% concentration of Al2O3 nano powder (LTMO + Al2O3). The materials were prepared by the modified auto combustion technique. The samples were characterized by X-ray diffraction. The powder X-ray diffraction pattern of pure LTMO at room temperature shows that sample is in single phase with no detectable secondary phases and the sample have a rhombohedral structure in hexagonal with the space group R3c. The XRD pattern of LTMO + 12% Al2O3 indicates the clear presence of Al2O3 nano phase in the composite. In the present study, the FTIR Spectroscopy of both samples was carried out. It is clear from the Vibrational assignment for the value of corresponding peak position of FTIR spectra that no extra unwanted impurity is present in samples. A quantitative analysis of the energy dispersive spectroscopy (EDS) data indicates that the observed concentration of elements are very close to the calculated values from its chemical formula. R-T measurements reveals that the addition of secondary phase in manganite strongly influenced on electronic and magnetoresistance behaviour. We summarise some of the salient features of the results.

Solvothermal Synthesis and Magnetic Properties of Fe3O4 Microspheres

2011 ◽  
Vol 393-395 ◽  
pp. 947-950
Author(s):  
De Hui Sun ◽  
Ji Lin Zhang ◽  
De Xin Sun
Keyword(s):  
Room Temperature ◽  
Size Range ◽  
Solvothermal Method ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Magnetic Investigation ◽  
Xrd Patterns ◽  
Fe3o4 Microspheres ◽  
Ftir Absorption Spectra

We synthesized Fe3O4 microspheres using a solvothermal method and characterized their morphologies, structures, surface property and magnetism by field emission scanning electron microscopy (FE-SEM), powder X-ray diffraction (XRD) patterns, Fourier transform infrared (FTIR) absorption spectra, and vibrating sample magnetometer (VSM). The results showed that the synthesized Fe3O4 microspheres with a tunable size range of ca. 80–200 nm are composed of many Fe3O4 collective nanoparticles. XRD pattern confirmed that the Fe3O4 microspheres belong to cubic structure. Magnetic investigation reveals that the Fe3O4 microspheres have higher saturation magnetization and negligible coercivity at room temperature.

Identification of a deleterious phase in photocatalyst based on Cd1 − xZnxS/Zn(OH)2by simulated XRD patterns

2017 ◽  
Vol 73 (3) ◽  
pp. 360-368 ◽  
Author(s):  
Svetlana Cherepanova ◽  
Dina Markovskaya ◽  
Ekaterina Kozlova
Keyword(s):  
Experimental Data ◽  
Thermogravimetric Analysis ◽  
Variable Temperature ◽  
Interlayer Distance ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Diffraction Peaks ◽  
Xrd Patterns

The X-ray diffraction (XRD) pattern of a deleterious phase in the photocatalyst based on Cd1 − xZnxS/Zn(OH)2contains two relatively intense asymmetric peaks withd-spacings of 2.72 and 1.56 Å. Very small diffraction peaks with interplanar distances of (d) ≃ 8.01, 5.40, 4.09, 3.15, 2.49 and 1.35 Å are characteristic of this phase but not always observed. To identify this phase, the XRD patterns for sheet-like hydroxide β-Zn(OH)2and sheet-like hydrozincite Zn5(CO3)2(OH)6as well as for turbostratic hydrozincite were simulated. It is shown that the XRD pattern calculated on the basis of the last model gives the best correspondence with experimental data. Distances between layers in the turbostratically disordered hydrozincite fluctuate aroundd≃ 8.01 Å. This average layer-to-layer distance is significantly higher than the interlayer distance 6.77 Å in the ordered Zn5(CO3)2(OH)6probably due to a deficiency of CO32−anions, excess OH−and the presence of water molecules in the interlayers. It is shown by variable-temperature XRD and thermogravimetric analysis (TGA) that the nanocrystalline turbostratic nonstoichiometric hydrozincite-like phase is quite thermostable. It decomposes into ZnO in air above 473 K.

Phase Composition and Morphology of Pottery Stone Microcrystalline Powders Synthesized by Hydrothermal Method

2013 ◽  
Vol 664 ◽  
pp. 620-624
Author(s):  
Amnouy Larpkasemsuk ◽  
Saowaroj Chuayjuljit ◽  
Dujreutai Pongkao Kashima
Keyword(s):  
Phase Composition ◽  
Hydrothermal Method ◽  
X Ray Diffraction ◽  
Major Phase ◽  
X Ray ◽  
Polyhedral Particles ◽  
Naoh Solution ◽  
Xrd Patterns ◽  
Aluminium Silicates ◽  
Scanning Electron

Pottery stone (PTS) microcrystalline powders were synthesized by a hydrothermal method using two concentrations of NaOH solution (2 M and 4 M) at 60, 80 and 120°C for 8 h in a Teflon- lined stainless steel autoclave. The phase composition and morphology of the samples were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The major phase compositions of the as-prepared PTS powders appeared in the XRD patterns are all silicate compounds such as tridymite, crystobalite, quartz, feldspar, albite, sodium silicate, analcime, hydroxyl-cancrinite and sodium aluminium silicates, depending on the NaOH concentration and the reaction temperature. Moreover, SEM micrographs showed the spherical polyhedral particles ranging from 8 to 14 µm in diameters and needle-like particles with a mean aspect ratio of 5.7 that obtained by the hydrothermal treatment operated at 120°C using 2 M and 4 M of NaOH, respectively.

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