scholarly journals Structural and Elastic Properties of Li-Ni Ferrite

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
S. A. Mazen ◽  
T. A. Elmosalami
Keyword(s):  
Cation Distribution ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Ceramic Method ◽  
X Ray ◽  
Lattice Constants ◽  
Wave Velocities ◽  
Rigidity Modulus ◽  
Binding Forces ◽  
Good Agreement

Li-Nickel ferrites with the chemical formula () have been prepared by the ceramic method. The spinel structure in homogenous state was realized by X-ray diffraction analysis. The lattice parameter has been determined for each composition and found to be nearly constant over the whole range of Ni concentration (= 0.83 nm ± 0.01). The cation distribution for each composition has been suggested. The experimental and theoretical lattice constants were found to be in good agreement with each other confirming the agreeability of the suggested cation distribution. The analysis of IR spectra indicates the presence of splitting in the absorption band due to the presence of small amounts of Fe2+ ions in the ferrite system. The force constants for tetrahedral and octahedral sites have been determined. Young’s modulus (E), rigidity modulus (G), bulk modulus (B), Debye temperature (), and transverse () and longitudinal () wave velocities have been determined. The variation of elastic moduli with composition has been interpreted in terms of binding forces between the atoms of spinal lattice.

Structural and electrical properties of Cu-doped Ni–Zn nanocrystalline ferrites for MLCI applications

2017 ◽  
Vol 31 (33) ◽  
pp. 1750318 ◽  
Author(s):  
D. Venkatesh ◽  
K. V. Ramesh
Keyword(s):  
Electrical Properties ◽  
Cation Distribution ◽  
Tetrahedral Site ◽  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Sem Images ◽  
X Ray ◽  
Structural And Electrical Properties ◽  
Phase Spinel ◽  
Diffraction Patterns

Polycrystalline Cu substituted Ni–Zn ferrites with chemical composition Ni[Formula: see text]Zn[Formula: see text]-Cu[Formula: see text]Fe2O4 (x = 0.00 to 0.25 in steps of 0.05) have been prepared by citrate gel autocombustion method. The samples for electrical properties have been sintered at 900[Formula: see text]C for 4 h. The X-ray diffraction patterns of all samples indicate the formation of single phase spinel cubic structure. The value of lattice parameter is decreases with increasing Cu concentration. The estimated cation distribution can be derived from X-ray diffraction intensity calculations and IR spectra. The tetrahedral and octahedral bond lengths, bond angles, cation–cation and cation–anion distances were calculated by using experimental lattice parameter and oxygen positional parameters. It is observed that Cu ions are distributed in octahedral site and subsequently Ni and Fe ions in tetrahedral site. The grain size of all samples has been calculated by Scanning Electron Microscopy (SEM) images. The variations in DC electrical resistivity and dielectric constant have been explained on the basis of proposed cation distribution.

scholarly journals IR Spectra, Elastic and Dielectric Properties of Li–Mn Ferrite

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
S. A. Mazen ◽  
N. I. Abu-Elsaad
Keyword(s):  
Dielectric Properties ◽  
Ir Spectra ◽  
Lattice Parameter ◽  
Exponential Factor ◽  
Ceramic Method ◽  
Ion Substitution ◽  
Rigidity Modulus ◽  
Binding Forces ◽  
Hopping Model ◽  
Model Frequency

Polycrystalline ferrites, , (where and ), were prepared by using ceramic method. Single phase cubic structure was confirmed by X-ray diffractometer. The lattice parameter “a” was found to increase with increasing ion substitution. IR spectra of the samples were recorded from 200 to 1000 cm−1. The two primary bands corresponding to tetrahedral and octahedral were observed at about 575 cm−1 and 370 cm−1, respectively. Elastic properties of these mixed ferrites were estimated as a function of composition. Young's modulus , rigidity modulus , bulk modulus , Debye temperature (), and mean sound velocity () were calculated from the transverse () and longitudinal () wave velocities. The variation of elastic moduli with composition was interpreted in terms of binding forces between the atoms of spinel lattice. AC conductivity and dielectric properties of the samples were measured at room temperature over 100 Hz–1 MHz. The electrical conduction mechanism could be explained with the electron hopping model. Frequency exponential factor was calculated and it was found between 0.4 and 0.8.

scholarly journals Effects Of Cd On Physical And Some Magnetic Properties Of Co-Cd Ferrites

1970 ◽  
Vol 35 (2) ◽  
pp. 229-235 ◽  
Author(s):  
Saroaut Noor ◽  
SS Sikder ◽  
M Samir Ullah ◽  
MA Hakim ◽  
Shireen Akhter
Keyword(s):  
Curie Temperature ◽  
Lattice Parameter ◽  
Initial Permeability ◽  
X Ray Diffraction ◽  
Ceramic Method ◽  
X Ray ◽  
Cobalt Ferrites ◽  
Vegard’S Law ◽  
Ray Density ◽  
Curie Temperature Tc

Polycrystalline samples of Cd substituted cobalt ferrites with composition Co1-xCdxFe2O4 (x = 0.0- 0.6 in steps of 0.1) were prepared by double sintering ceramic method. The samples were sintered at 1050°C for 3 hours. X-ray diffraction pattern of the samples showed single phase cubic spinel structure. It was found that the lattice parameter increases linearly with increasing Cd content following Vegard’s law. The apparent density and X-ray density exhibited similar behavior. The Curie temperature Tc has been determined from the temperature dependence of permeability. It was found that the Curie temperature continuously decreased with increasing Cd content and is attributed to the weakening of JAB exchange interaction. The initial permeability, μ' increases with increasing Cd content up to x = 0.6 and then decreases. Key words: Co-Cd ferrite; Lattice parameter; Permeability DOI: http://dx.doi.org/10.3329/jbas.v35i2.9429 JBAS 2011; 35(2): 229-235

scholarly journals X-Ray Diffraction and Density Distribution Measurements on the Al2O3 Crystals Grown by Czochralski Method with Different Pull Rate

2015 ◽  
Vol 1 (1) ◽  
pp. 1 ◽  
Author(s):  
Hamdan Hadi Kusuma
Keyword(s):  
Density Measurement ◽  
Czochralski Method ◽  
X Ray Diffraction ◽  
Powder Diffraction File ◽  
Hexagonal System ◽  
X Ray ◽  
Lattice Constants ◽  
The Difference ◽  
Measurement Base ◽  
Good Agreement

The Al<sub>2</sub>O<sub>3</sub> crystal has been done by Czochralki Method with different pull rate. The effect of pull rate on the Al<sub>2</sub>O<sub>3</sub> single crystal was characterized using X-ray diffraction and density measurement. Base on the XRD result of Al<sub>2</sub>O<sub>3</sub> crystal, which belongs to the hexagonal system, except for the difference in the relative intensity, present diffraction data which are found to be in good agreement with those of the powder diffraction file (PDF) 43-1484 provided by the JCPDS. It was observed the structure with symmetry group <em>D</em><sup>6</sup><sub>3d</sub>–<em>R</em>3<em>C </em>and has lattice constants being <em>a </em>= 4.759 Å, <em>c</em> = 12.99 Å. The density of the crystals increased with the pull rate. This phenomenon is caused by the speed of the pull rate crystal that causes changes in the heat flow in the furnace and then changed homogeneities of species distribution of atoms along the crystal. © 2015 JNSMR UIN Walisongo. All rights reserved.

scholarly journals X-ray, IR and SEM studies on some Li-Cd ferrites

YMER Digital ◽  
2021 ◽  
Vol 20 (12) ◽  
pp. 333-340
Author(s):  
Sudhir Kulkarni ◽  
Keyword(s):  
Grain Size ◽  
Room Temperature ◽  
Single Phase ◽  
Lattice Parameter ◽  
Lithium Ferrite ◽  
Cadmium Content ◽  
X Ray Diffraction ◽  
Ceramic Method ◽  
X Ray ◽  
Single Phase Formation

Lithium-Cadmium ferrites with general formula Li0.5-x/2 Fe2.5-x/2 Cdx O4 (with x = 0,0.1,0.2....,0.7) were prepared by standard ceramic method. X-ray diffraction studies confirms single phase formation and lattice parameters were calculated. The crystal structure is cubic and lattice parameter increases with increasing Cd content. The infrared absorption (IR) spectra of all the samples were recorded in the range 200-800 cm-1 at room temperature in the KBr medium. Lithium ferrite shows four principal bands and some shoulders have been observed. The force constants Kt and Ko were calculated using Waldron's analysis. Scanning electron microscopy studies shows increase in grain size up to x = 0.1 and then the grain size decreases with increase in cadmium content.

Étude du système U-Sr-O par diffraction X à haute température

1999 ◽  
Vol 77 (8) ◽  
pp. 1384-1393 ◽  
Author(s):  
André Pialoux ◽  
Bernard Touzelin
Keyword(s):  
High Temperature ◽  
Lattice Parameter ◽  
Reduced Form ◽  
X Ray Diffraction ◽  
Constant Composition ◽  
X Ray ◽  
Lattice Constants ◽  
Metallic Oxides ◽  
Composition Variation ◽  
Fluorite Type

High-temperature X-ray diffraction (293 [Formula: see text] T(K) [Formula: see text] 1773) is used to investigate the reaction between strontium monoxide and uranium dioxide under controlled atmosphere (105 [Formula: see text] [Formula: see text] (Pa) [Formula: see text] 10-24), with lattice parameter measurements and composition estimates of the different uranates obtained. Thus, with a Sr/U = 1 sample, we successively observe the phases: (a) orthorhombic α-"SrUO4", whose reduction (3.67 [Formula: see text] O/U [Formula: see text] 3.62) is shown by a constant volume of the cell (V = 0.367 nm3) between 1173 et 1373 K; (b) rhombohedral β-"SrUO4", which shows a large composition variation between the metastable oxidized form (β-SrUO3.60) below 1108 K and the stable conjugate reduced form (β'-SrUO3.11) at whatever temperature; (c) "SrUO3" of constant composition (O/U [Formula: see text] 3) between 293 and 1533 K, then variable (O/U < 3) above 1533 K, with a probable second-order transformation (α-Pnma, β-Imma) for this distorted perovskite near 1073 K; (d) fluorite type U1-δSrδO2-δ solid solution for which a maximal account in SrO (δ [Formula: see text] 0.25) induces a 0.5 % thermal expansion parameter in comparison with UO2.00. A pseudo-binary "SrUO3"-"SrUO4" phase diagram is propounded. With a sample compound of Sr/U = 3, the monoclinic "Sr3UO6" perovskite is stable under [Formula: see text] [Formula: see text] 105 Pa up to 1373 K. On the other hand, in reducing atmosphere ([Formula: see text] [Formula: see text] 10-19 Pa), it becomes orthorhombic "Sr3UO5" with much greater lattice constants at every temperature.Key words: high-temperature X-ray diffraction, reactivity in metallic oxides, U-Sr-O system, nuclear fuels.

Powder X-ray diffraction data of new bismuth yttrium gadolinium oxides

2008 ◽  
Vol 23 (3) ◽  
pp. 255-258
Author(s):  
M. Alizadeh ◽  
K. Ahmadi ◽  
A. Maghsudipour ◽  
F. Moztarzadeh
Keyword(s):  
Diffraction Data ◽  
Solid State Reaction Method ◽  
Cubic Phase ◽  
Powder Diffraction Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lattice Constants ◽  
Cell Dimensions ◽  
Unit Cell Dimensions ◽  
Good Agreement

X-ray powder diffraction data for five new bismuth yttrium gadolinium oxide compounds synthesized by solid state reaction method are reported. The unit cell dimensions were determined from X-ray diffraction methods, using CuKα radiation, and evaluated by indexing programs. The cubic phase was the sole crystalline phase detected by X-ray diffraction analysis in Bi0.88Y0.06Gd0.06O1.5, Bi0.88Y0.08Gd0.04O1.5, Bi0.82Y0.09Gd0.09O1.5, Bi0.82Y0.12Gd0.06O1.5, and Bi0.82Y0.06Gd0.12O1.5 samples with lattice constants of a=5.5371(1) Å, a=5.5368(1) Å, a=5.5303(2) Å, a=5.53487(8) Å, and a=5.5279(1) Å, respectively. The results are in good agreement with those reported for bismuth yttrium oxide (Bi0.75Y0.25)O1.5 (PDF 01-084-1450).

Analysis of stresses and crystal structure in the surface layer of hexagonal polycrystalline materials: a new methodology based on grazing incidence diffraction

2016 ◽  
Vol 49 (1) ◽  
pp. 85-102 ◽  
Author(s):  
Marianna Marciszko ◽  
Andrzej Baczmański ◽  
Chedly Braham ◽  
Mirosław Wróbel ◽  
Wilfrid Seiler ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Stress Gradient ◽  
Grazing Incidence ◽  
Lattice Parameter ◽  
Polycrystalline Materials ◽  
X Rays ◽  
X Ray Diffraction ◽  
Surface Layers ◽  
X Ray ◽  
Good Agreement

The multireflection grazing-incidence X-ray diffraction (MGIXD) method is commonly used to determine a stress gradient in thin surface layers (about 1–20 µm for metals). In this article, the development of MGIXD to enable the determination not only of stresses but also of thec/aratio and thea0strain-free lattice parameter in hexagonal polycrystalline materials is presented and tested. The new procedure was applied for the results of measurements performed using a laboratory X-ray diffractometer and synchrotron radiation. The evolution of stresses and lattice parameters with depth was determined for Ti and Ti-alloy samples subjected to different mechanical surface treatments. A very good agreement of the results obtained using three different wavelengths of synchrotron radiation as well as classical X-rays (CuKα radiation) was found.

Powder x-ray diffraction study of a cryptomelane-type manganic acid and its alkali cation exchanged forms

1993 ◽  
Vol 8 (12) ◽  
pp. 3145-3150 ◽  
Author(s):  
Masamichi Tsuji ◽  
Sridhar Komarneni
Keyword(s):  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Lattice Parameter ◽  
Exchange Capacity ◽  
Alkali Cation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Steep Decrease ◽  
Exchange Properties ◽  
Good Agreement

Cryptomelane-type manganic acid (CMA), H2Mn8O16 · 2.4H2O, with a theoretical cation exchange capacity of 2.70 meq/g, was prepared and its cation exchange properties were studied as a function of XM which is defined by the ratio of uptake in meq/g to the theoretical capacity. Plots of the corrected selectivity coefficients log KHM vs the fractional exchange M for alkali metal ions on a 2 × 2 type tunnel-structured manganic acid showed a gradual decrease in small XMM regions and a steep decrease in large XMM) were 0.92 for Li+, 0.74 for Na+ and K+, 0.67 for Rb+, and 0.44 for Cs+. These maximums have been attributed to steric limitation as well as a limit on the expansion of the crystal lattice. Some x-ray diffraction (XRD) data of alkali cation exchanged forms were in good agreement with the XRD data of synthetic alkali CMA phases as given in the cards by the Joint Committee on Powder Diffraction Standards (JCPDS). The lattice parameter a0 has been found to depend on the exchanged amounts and the nature of the cations involved, while the c0 value remained almost the same irrespective of the amount of exchange or the nature of the cations.

Cation distribution, structural and electric studies on cadmium substituted nickel–zinc ferrite

2014 ◽  
Vol 28 (19) ◽  
pp. 1450155 ◽  
Author(s):  
B. B. V. S. Vara Prasad
Keyword(s):  
Cation Distribution ◽  
Structural Parameters ◽  
Dielectric Measurements ◽  
X Ray Diffraction ◽  
Abrupt Increase ◽  
X Ray ◽  
Lattice Constants ◽  
Dc Electrical Conductivity ◽  
Nickel Zinc ◽  
Dielectric Constant And Loss

The structural and electric properties of Ni 0.65-x Zn 0.35 Cd x Fe 2 O 4 (0 ≤ x ≤ 0.2) prepared by standard ceramic technique, have been studied. For all x values, X-ray powder diffraction was performed and the lattice constants and oxygen parameters were drawn from experimental data. Based on these values, other structural parameters like cation–cation, cation–anion distances, bond angles and hopping length were calculated, and the cation distribution was proposed by comparing observed and calculated X-ray diffraction intensities. It was found that substitution of larger cadmium into the lattice resulted in a significant change in the structural parameters. The microstructure of the samples was investigated using SEM micrographs and we found a substantial grain growth (observed mainly for x = 0.16 and 0.20) due to cadmium diffusion. Carrier mobilities for all samples were drawn from our DC electrical conductivity results and the variation of mobility with composition and temperature is presented. Dielectric measurements were performed at a standard frequency 1 kHz and the dielectric constant and loss factor were found to decrease first from x = 0 to x = 0.12 with the abrupt increase above this composition.

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