scholarly journals ANALISIS PARAMETER MIKROSTRUKTUR NANOPARTIKEL Mn1-xZnxFe2O4 BERDASARKAN POLA DIFRAKSI SINAR X

2019 ◽  
Vol 8 (1) ◽  
pp. 23
Author(s):  
I Putu Tedy Indrayana

The Mn-Zn Ferit is a magnetic material which has potential applications for data storage device, the inductor coil and catalysis. This material has unique electrical and optical properties. Their properties are microstructural dependent. In this work, we studied the microstructural parameters of Mn1-xZnxFe2O4 which x assigns the mole fraction of Mn2+ and Zn2+ (x = 0.6; 0.7 and 0.8). Samples were synthesized by using coprecipitation method and NaOH as a coprecipitant. Microstructural parameters were investigated based on X-ray diffraction pattern. The crystallite size and strain were determined by using Size-strain plot (SSP) method. The crystallite size of nanoparticles is in a range of 18.9 nm – 24.8 nm, while the strain is in a range of 0.0012 – 0.0099. The lattice parameter is in a range of 8.531Ǻ - 8.567Ǻ bigger than the values were calculated theoretically according to the theoretical cation distribution model. The cation distribution in crystal lattice takes important rule in determining the microstructural parameters of nanoparticles. 

Carbon Trends ◽  
2021 ◽  
pp. 100071
Author(s):  
Keith R. Hallam ◽  
James Edward Darnbrough ◽  
Charilaos Paraskevoulakos ◽  
Peter J. Heard ◽  
T. James Marrow ◽  
...  

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
M. Mhadhbi ◽  
M. Khitouni ◽  
L. Escoda ◽  
J. J. Suñol ◽  
M. Dammak

A nanostructured disordered Fe(Al) solid solution was obtained from elemental powders of Fe and Al using a high-energy ball mill. The transformations occurring in the material during milling were studied with the use of X-ray diffraction. In addition lattice microstrain, average crystallite size, dislocation density, and the lattice parameter were determined. Scanning electron microscopy (SEM) was employed to examine the morphology of the samples as a function of milling times. Thermal behaviour of the milled powders was examined by differential scanning calorimetry (DSC). The results, as well as dissimilarity between calorimetric curves of the powders after 2 and 20 h of milling, indicated the formation of a nanostructured Fe(Al) solid solution.


2017 ◽  
Vol 31 (33) ◽  
pp. 1750318 ◽  
Author(s):  
D. Venkatesh ◽  
K. V. Ramesh

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.


2009 ◽  
Vol 42 (2) ◽  
pp. 174-178 ◽  
Author(s):  
S. Roncallo ◽  
O. Karimi ◽  
K. D. Rogers ◽  
D. W. Lane ◽  
S. A. Ansari

With the demand for higher rates of discovery in the materials field, characterization techniques that are capable of rapidly and reliably surveying the characteristics of large numbers of samples are essential. A chemical combinatorial approach using thin films can provide detailed phase diagrams without the need to produce multiple, individual samples. This is achieved with compositional gradients forming high-density libraries. Conventional raster scanning of chemical or structural probes is subsequently used to interrogate the libraries. A new, alternative approach to raster scanning is introduced to provide a method of high-throughput data collection and analysis using an X-ray diffraction probe. Libraries are interrogated with an extended X-ray source and the scattering data collected using an area detector. A simple technique of `partitioning' this scattering distribution enables determination of information comparable to conventional raster scanned results but in a dramatically reduced collection time. The technique has been tested using synthetic X-ray scattering distributions and those obtained from contrived samples. In all cases, the partitioning algorithm is shown to be robust and to provide reliable data; discrimination along the library principal axis is shown to be ∼500 µm and the lattice parameter resolution to be ∼10−3 Å mm−1. The limitations of the technique are discussed and future potential applications described.


1997 ◽  
Vol 12 (3) ◽  
pp. 175-179 ◽  
Author(s):  
K. D. Rogers

X-ray diffraction data has been collected from biological calcific mineral associated with human bone, breast tissue, ureteric calculi, heart valve, and aorta. All the materials are shown to have a nominal calcium hydroxyapatite structure and Rietveld analysis has been performed to extract microstructural information. All refinements achieved a final Rwp value of <10%. The lattice parameter ranges are a=9.375(3)(breast)−9.4316(8)(heartvalve), c=6.866(1)(uretericcalculi) −6.899(1)(rib), and crystallite size range from 40 Å (breast) to 99 Å (ureteric calculi). A correlation between crystallite size estimates from this Rietveld analysis and line profile methods is demonstrated. The results are supported by an infrared study and previous data from alternative techniques. Thus, it is demonstrated that the microstructure of these materials may be characterised by application of the Rietveld method.


2021 ◽  
Vol 8 (2) ◽  
pp. 201883
Author(s):  
Edwin Akongnwi Nforna ◽  
Patrice Kenfack Tsobnang ◽  
Roussin Lontio Fomekong ◽  
Hypolite Mathias Kamta Tedjieukeng ◽  
John Ngolui Lambi ◽  
...  

Samples of cobalt-doped neodymium orthoferrite compounds, NdCo x Fe 1−x O 3 (0.0 ≤ x ≤ 0.5) were synthesized via glycine auto-combustion between 250 and 300°C and calcined at 500°C for 2 h. X-ray diffraction showed that all compounds had an orthorhombic perovskite structure with space group Pbnm. Increasing cobalt doping gradually reduced the lattice parameters and contracted the unit cell volume. Both X-ray diffraction and scanning electron microscopy showed that the particles were spherical and in the nano-sized range (19–52 nm) with pores between grains. Vibrating sample magnetometry at room temperature indicated that NdFeO 3 has a high coercive field (1950 Oe) and cobalt substitution for iron led to a decrease in the coercive field, saturation and remanent magnetization, which was as a result of decreased magnetic moments in the crystal and reduced canting of the FeO 6 octahedra. The increase in magnetization and coercive fields with increase of Co was connected to the microstructure (bond lengths and angles, defects, pores, grain boundaries) and crystallite size. The compounds NdCo x Fe 1−x O 3 show antiferromagnetism with weak ferromagnetism due to uncompensated non-collinear moments. These compounds could serve as prototypes for tuning the properties of magnetic materials (ferromagnetic and antiferromagnetic) with potential applications in data storage, logic gates, switches and sensors.


2021 ◽  
Author(s):  
Adel Maher Wahba ◽  
Bahaa Eldeen M. Moharam ◽  
Aya Fayez Mahmoud

Abstract In this work, the impact of nonstoichiometric substitution of Fe3+ cations by Ni2+ ones on the structural and magnetic properties of Co0.5Ni0.5+xFe2-xO4 (0.0 ≤ x ≤ 0.4) nanoferrites synthesized by citric autocombustion method. The cubic phase purity for sintered samples were verified by XRD patterns and FTIR spectra. The crystallite size and microstrain were deduced using Williamson-Hall method. The estimated crystallite size ranges from 55 to 89 nm in agreement with TEM microimages. Hysteresis loops traced using VSM prevailed a regular reduction of saturation magnetization with Ni substitution. Relied on the experimental data of XRD, FTIR, and VSM, cation distribution has been suggested, according to which the nonstoichiometric substitution was compensated by the appearance of higher valance states of Fe, Ni, and Co cations. The suggested cation distribution successfully explained the recorded data of lattice parameter, crystallite size, IR frequencies, magnetization and coercivity.


2015 ◽  
Vol 34 (1) ◽  
pp. 39
Author(s):  
Stanko Popović ◽  
Željko Skoko

The microstructure is very important in research aimed to the development of new materials. The microstructural parameters, crystallite size, crystallite size distribution, crystallite strain, dislocation density and stacking fault probability, play a major role in physical and chemical properties of the material. These parameters can be determined by a proper analysis of X-ray diffraction line profile broadening. The observed XRD line profile of the studied sample, <em>h</em>(<em>ε</em>), is the convolution of the instrumental profile, <em>g</em>(<em>ε</em>), inherent in diffraction, and pure diffraction profile, <em>f</em>(<em>ε</em>), caused by small crystallite (coherent domain) sizes, by faultings in the sequence of the crystal lattice planes, and by the strains in the crystallites. That is, <em>f</em>(<em>ε</em>) is the convolution of the crystallite size/faulting profile, <em>p</em>(<em>ε</em>), and the strain profile, <em>s</em>(<em>ε</em>). The derivation of <em>f</em>(<em>ε</em>) can be performed from the measured <em>h</em>(<em>ε</em>) and <em>g</em>(<em>ε</em>) by the Fourier transform method, usually referred to as the Stokes method. That method does not require assumptions in the mathematical description of <em>h</em>(<em>ε</em>) and <em>g</em>(<em>ε</em>). The analysis of <em>f</em>(<em>ε</em>) can be done by the Warren-Averbach method, which is applied to the Fourier coefficients obtained by the deconvolution. On the other hand, simplified methods (which may bypass the deconvolution) based on integral widths may be used, especially in studies where a good relative accuracy suffices. In order to obtain the relation among integral widths of <em>f</em>(<em>ε</em>), <em>p</em>(<em>ε</em>) and <em>s</em>(<em>ε</em>), one assumes bell-shaped functions for <em>p</em>(<em>ε</em>) and <em>s</em>(<em>ε</em>). These functions are routinely used in the profile fitting of the XRD pattern and in the Rietveld refinement of the crystal structure. The derived crystallite size and strain parameters depend on the assumptions for the profiles <em>p</em>(<em>ε</em>) and <em>s</em>(<em>ε</em>). Integral width methods overestimate both strain and crystallite size parameters in comparison to the Warren-Averbach-Stokes method. Also, the crystallite size parameter is more dependent on the accuracy, with which the profile tails are measured and how they are truncated, than it is the strain parameter. The integral width also depends on the background level error of the pure diffraction profile. The steps and precautions, which are necessary in order to minimize the errors, are suggested through simple examples. The values of the crystallite size and strain parameters, obtained from integral widths derived by the Stokes deconvolution, are compared with those which followed from the Warren-Averbach treatment of broadening. Recent approaches in derivation of microstructure are also mentioned in short.


2014 ◽  
Vol 803 ◽  
pp. 362-366 ◽  
Author(s):  
Dewi Suriyani Che Halin ◽  
Norainiza Saud ◽  
Haiza Haroon

Cuprous oxide thin films were prepared by sol-gel method was successfully deposited onto n-Si substrate. Sol solutions were prepared by dissolving copper (II) acetate in isopropyl alcohol. Diethanolamine and glucopone were added into the sol solution to dissolve the copper (II) acetate rapidly to prevent the precipitation of blue copper (II) acetate. Crystalline phases are identified by X-ray diffraction (XRD) and the crystallite size is estimated by using Scherrer’s formula which indicates that the largest crystallite size is 41.84 nm with the lowest lattice parameter 4.25 Å. The optical band gap of the films is determined by optical absorption technique and the surface morphologies of films are analyzed by scanning electron microscopy (SEM). The SEM micrographs show that the particles agglomerate with different shapes and sizes.


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