scholarly journals Synthesis, structural, W-H plot and size-strain analysis of nano cobalt doped MgFe2O4 ferrite

2020 ◽  
Vol 52 (3) ◽  
pp. 349-358
Author(s):  
Rakesh Vishwaroop ◽  
Shridhar Mathad
Keyword(s):  
Tetrahedral Site ◽  
Strain Analysis ◽  
Lattice Parameter ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Ionic Radii ◽  
Crystallite Sizes ◽  
Structural Attribute ◽  
Diffraction Lattice ◽  
Co Precipitation

In this study we have investigated structural attribute of Co+2 doped MgFe2O4. Synthesis of Mg1-xCoxFe2O4 ferrite was carried out using co-precipitation method. The formation of spinal ferrite was confirmed through X-ray diffraction. Lattice parameter found to be 8.376748 ? and crystallite sizes in the range 180-365 ? are observed. Various parameters like dislocation density (?D); mechanical properties (strain), Hopping length {tetrahedral site (LA) and octahedral site (LB)}, Bond length (A-O and B-O), and Ionic radii (rA and rB) were reported. The W-H plot and Size-Strain plots were extensively studied and the results have been correlated.

The Mixed Magnetic Property of Co0.76Cu0.74[Fe(CN)6]·7.5H2O

2018 ◽  
Vol 71 (11) ◽  
pp. 914
Author(s):  
Yanfang Xia ◽  
Min Liu ◽  
Duxin Li
Keyword(s):  
Magnetic Field ◽  
Magnetic Moment ◽  
Effective Magnetic Moment ◽  
Lattice Parameter ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Patterns ◽  
Co Precipitation ◽  
The Magnetic Field

Co0.76Cu0.74[Fe(CN)6]·7.5H2O was prepared as a powder by a chemical co-precipitation method. The powder X-ray diffraction patterns were indexed to the typical face-centred cubic structure with the lattice parameter a 10.55(2) Å. The temperature dependence of the χ−1 curve obeys the Curie–Weiss law (χ = C/(T – θ)) in the temperature range of 180–300 K. According to Curie–Weiss law, the calculated θ value is −54.82 K. In the paramagnetic state at 300 K, the effective magnetic moment (μeff = (8χT)1/2) is 3.58 μB per formula unit. The calculated theoretical effective magnetic moment is 4.06 μB. The magnetic field cooling measurements under a 200 Oe applied magnetic field show that the saturation magnetization value at 2 K of the complex Co0.76Cu0.74[Fe(CN)6]·7.5H2O is 1.528 emu g−1.

MAGNETIC PROPERTIES AND STRUCTURE OF NANO-SIZE NiZn FERRITE SYNTHESIZED BY THE REFLUXING CO-PRECIPITATION METHOD

2009 ◽  
Vol 23 (04) ◽  
pp. 633-642 ◽  
Author(s):  
YI ZHANG ◽  
QIGANG JIAO ◽  
YA ZHAI ◽  
XIAOJUN BAI ◽  
JUN DU ◽  
...  
Keyword(s):  
Room Temperature ◽  
Hyperfine Magnetic Field ◽  
Lattice Parameter ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Tetrahedral Sites ◽  
Zn Concentration ◽  
Zn Content ◽  
Co Precipitation ◽  
Nano Size

A series of nanoparticle powders of Ni 1-x Zn x Fe 2 O 4 (x = 0, 0.3, 0.4, 0.5, 0.6 and 0.7) ferrites were synthesized by the refluxing method at relatively low temperatures. X-ray diffraction measurements were performed to yield the grain size of the particles as a function of the amount x of Zn substitution and the lattice parameter was found to increase with increasing x. Mössbauer spectroscopy was performed at room temperature. The spectra exhibit ferromagnetic hyperfine splitting sextet peaks with a doublet peak overlapped at its center as Zn contents x < 0.6. The fitted hyperfine magnetic field of the octahedral sublattice and tetrahedral sublattice all decrease with increasing Zn content. The area of the tetrahedral sublattice decreases with increasing x and that of the octahedral sites increases for low Zn concentration, as a result of substitution of iron by zinc in the tetrahedral sites. The area of the doublet increases constantly. Systematic magnetization measurements gave evidence that the doublet in the spectra originated from the superparamagnetism of the particles at room temperature as Zn content x < 0.6.

Effect of Gallium Loading on Reducibility and Dispersion of Copper-Based Catalyst

2015 ◽  
Vol 659 ◽  
pp. 211-215
Author(s):  
Parncheewa Udomsap ◽  
Somsak Supasitmongkol
Keyword(s):  
Copper Oxide ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Reduction Peak ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Crystallite Sizes ◽  
Copper Phase ◽  
Temperature Programmed ◽  
Co Precipitation

The effect of gallium-promoted copper-based catalysts has been investigated in connection with the characteristic of the active copper phase. CuO-ZnO-Ga2O3catalysts with different gallium loadings were prepared using oxalate co-precipitation method. The effects of gallium loading on the properties of catalysts were studied by means of X-ray diffraction (XRD), transmission electron microscopy (TEM) and temperature-programmed reduction (TPR). The dispersion and metal area of copper were also determined by dissociative nitrous (N2O) adsorption technique conducted on a metal dispersion analyzer (BELCAT). The TPR profiles showed that the presence of two different reduction regions in the CuO-ZnO catalysts can be attributed to the reduction of highly dispersed copper oxide species (reduced at 246 °C) and bulk-like CuO (reduced at above 390 °C). By contrast, the only low-temperature reduction peak was presented in the TPR profiles after the Ga2O3loading was higher than 4 wt%. With the same molar ratio (Cu/Zn = 2:1), the reducibility of CuO-ZnO-Ga2O3was found to be more facile than CuO-ZnO due to the lower copper oxide crystallite sizes of gallium-promoted catalysts. Higher Ga2O3loadings resulted in an increase in both copper dispersion and metal surface area of all the catalysts studied in good agreement with the reduction behaviors in the TPR profiles, although all the gallium-promoted catalysts were slightly different for the reducibility.

scholarly journals X-RD, TEM, Magnetic Studies on NixZn1-xFe2O4 (Where x= 0.2, 0.4, 0.5, 0.6 and 0.8) Nano Scale Particles by Chemical Co-Precipitation Method

2015 ◽  
Vol 60 ◽  
pp. 20-24
Author(s):  
B. Suryanarayana ◽  
V. Raghavendra ◽  
K. Chandra Mouli
Keyword(s):  
Average Particle Size ◽  
Lattice Parameter ◽  
Precipitation Method ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Magnetic Studies ◽  
Zinc Nanoparticles ◽  
X Ray ◽  
Xrd Patterns ◽  
Co Precipitation

Nickel zinc nanoparticles NixZn1-xFe2O4 (where x= 0.2, 0.4, 0.5, 0.6 and 0.8) by Chemical Co-Precipitation method. The samples were characterised by X-ray diffraction (XRD), TEM, VSM .The powders of XRD patterns confirm a single spinel crystalline phase with cubic structure formation with no indication of any other secondary or unidentified phase. The lattice parameter changed from 8.336 Å to 8.382 Å. The average particle size ranged 20 to 80 nm was observed by TEM.

Microstructures, Electrical and Magnetic Properties of Zn Doped Co Nanoferrites

2012 ◽  
Vol 510-511 ◽  
pp. 221-226 ◽  
Author(s):  
M. Akram ◽  
M. Anis-ur-Rehman ◽  
M. Mubeen ◽  
M. Ali
Keyword(s):  
Magnetic Properties ◽  
Electrical Transport ◽  
Room Temperature ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Electrical Transport Properties ◽  
X Ray ◽  
Electrical And Magnetic Properties ◽  
Crystallite Sizes ◽  
Co Precipitation

Non toxicity, bio compatibility and nanometer sizes regime which is comparable to the size of a cell, makes nanocrystalline Co ferrites particles very proficient. In the present research Zn doped cobalt ferrites were prepared by the chemical co-precipitation method and characterized by X-ray diffraction (XRD) at room temperature for structural analysis. X-ray diffraction patterns confirmed the FCC spinel structure of synthesized particles. Crystallite sizes were calculated from the most intense peak (311) using the Debye-Scherrer formula. The obtained crystallite sizes were in nanometer range for all the samples synthesized at reaction temperature of 70°C. Then samples were sintered at 550°C for 2 hours, characterized again by X-ray diffraction at room temperature. The crystallite sizes and lattice constants for all the samples were calculated again from the data obtained by XRD. DC electrical resistivity and AC electrical transport properties were analyzed. The magnetic properties such as coercivity (Hc) and remanence (Mr) of Co1-xZnxFe2O4for x = 0.0, 0.2, 0.4 were measured at room temperature by vibrating sample magnetometer. Coercivity and remanence were found maximum with minimum value of Zn in Co1-xZnxFe2O4.Observed structural and conduction properties of synthesized nanomaterials were correlated.

Dielectric Properties of Y3Fe5O12 (YIG) Prepared at Different Molarities of NaOH

2020 ◽  
Vol 13 (3) ◽  
pp. 221-226
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Yttrium Iron Garnet ◽  
Lattice Parameter ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Yttrium Iron ◽  
X Ray ◽  
Co Precipitation ◽  
Iron Garnet

Abstract: In this study, Yttrium Iron Garnet (Y3Fe5O12) (YIG) powders were synthesized via co-precipitation method, followed by calcining the precipitates at 1100˚C. The garnets produced were obtained from aqueous iron and yttrium chloride mixtures using different molarities of NaOH (M=2, 3, 4 and 5) at pH=12. The phase formation and crystallography were investigated using X-ray diffraction (XRD), the morphology was investigated using transmission electron microscopy (TEM) and the dielectric properties were measured using an impedance analyzer in the frequency range 0.5 - 5MHz, in a temperature range 22 - 350˚C. X-ray diffraction peaks showed the formation of cubic YIG with lattice parameter varying between 12.334 and 12.339 Å. The grain size, measured from TEM images, decreased with the increase of the molarity of NaOH. Plots of the real part of the dielectric constant ε′, the imaginary part of the dielectric constant ε'', loss tangent tan δ and ac conductivity σac as functions of frequency and temperature, respectively, were obtained. It was observed that the highest values of the dielectric constant were obtained in the 2M sample. Keywords: Dielectric properties, Yttrium Iron Garnet (YIG), Co-precipitation method, NaOH molarity.

Magnetic and dielectric properties of BiFeO3 nanoparticles

2015 ◽  
Vol 7 (2) ◽  
pp. 1393-1403
Author(s):  
Dr R.P VIJAYALAKSHMI ◽  
N. Manjula ◽  
S. Ramu ◽  
Amaranatha Reddy
Keyword(s):  
Diffuse Reflectance Spectrum ◽  
Precipitation Method ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
Bifeo3 Nanoparticles ◽  
Transmission Electron ◽  
Multiferroic Bifeo3 ◽  
Pure Phase ◽  
Simple Chemical ◽  
Co Precipitation

Single crystalline nano-sized multiferroic BiFeO3 (BFO) powders were synthesized through simple chemical co-precipitation method using polyethylene glycol (PEG) as capping agent. We obtained pure phase BiFeO3 powder by controlling pHand calcination temperature. From X-ray diffraction studies the nanoparticles were unambiguously identified to have a rhombohedrally distorted perovskite structure belonging to the space group of R3c. No secondary phases were detected. It indicates single phase structure. EDX spectra indicated the appearance of three elements Bi, Fe, O in 1:1:3. From the UV-Vis diffuse reflectance spectrum, the absorption cut-off wavelength of the BFO sample is around 558nm corresponding to the energy band gap of 2.2 eV. The size (60-70 nm) and morphology of the nanoparticles have been analyzed using transmission electron microscopy (TEM).   Linear M−H behaviour and slight hysteresis at lower magnetic field is observed for BiFeO3 nanoparticles from Vibrating sample magnetometer studies. It indicates weak ferromagnetic behaviour at room temperature. From dielectric studies, the conductivity value is calculated from the relation s = L/RbA Sm-1 and it is around 7.2 x 10-9 S/m.

scholarly journals Photoluminescent Properties of Hydroxyapatite and Hydroxyapatite/Multi-Walled Carbon Nanotube Composites

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 832
Author(s):  
Edna X. Figueroa-Rosales ◽  
Javier Martínez-Juárez ◽  
Esmeralda García-Díaz ◽  
Daniel Hernández-Cruz ◽  
Sergio A. Sabinas-Hernández ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Hexagonal Phase ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Multi Walled Carbon Nanotube ◽  
Nanotube Composites ◽  
Carbon Nanotube Composites ◽  
Co Precipitation ◽  
Functionalized Mwcnts

Hydroxyapatite (HAp) and hydroxyapatite/multi-walled carbon nanotube (MWCNT) composites were obtained by the co-precipitation method, followed by ultrasound-assisted and microwave radiation and thermal treatment at 250 °C. X-ray diffraction (XRD) confirmed the presence of a hexagonal phase in all the samples, while Fourier-transform infrared (FTIR) spectroscopy elucidated the interaction between HAp and MWCNTs. The photoluminescent technique revealed that HAp and the composite with non-functionalized MWCNTs present a blue luminescence, while the composite with functionalized MWCNTs, under UV-vis radiation shows an intense white emission. These findings allowed presentation of a proposal for the use of HAp and HAp with functionalized MWCNTs as potential materials for optoelectronic and medical applications.

Photocatalytic Activity of Fe-Doped ZnO/Montmorillonite Nanocomposite for Degradation of Malachite Green

2015 ◽  
Vol 827 ◽  
pp. 19-24 ◽  
Author(s):  
Nur Afifah ◽  
Nadia Febiana Djaja ◽  
Rosari Saleh
Keyword(s):  
Photocatalytic Activity ◽  
Malachite Green ◽  
Organic Dyes ◽  
Uv Light ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Spin Resonance ◽  
Doped Zno ◽  
Co Precipitation

In this study, the photocatalytic activity of pure Fe- doped ZnO and Fe- doped ZnO/Montmorillonite nanocomposite has been investigated for the degradation of malachite green under UV light irradiation. Both photocatalysts were synthesized using co-precipitation method and characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, Fourier-transform infrared absorption, and electron spin resonance. The results showed that the photocatalytic efficiency is better in the presence of montmorillonite compared to pure Fe- doped ZnO. To detect the possible reactive species involved in degradation of organic dyes control experiments with introducing scavengers into the solution of organic dyes were carried out. It is found that electron plays an important role in the degradation of malachite green.

Microstructure Characterization of Metal Mixed Oxides

MRS Advances ◽  
2017 ◽  
Vol 2 (64) ◽  
pp. 4025-4030 ◽  
Author(s):  
T. Kryshtab ◽  
H. A. Calderon ◽  
A. Kryvko
Keyword(s):  
Mixed Oxides ◽  
Profile Analysis ◽  
Atomic Resolution ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Reconstruction Procedure ◽  
Transmission Electron ◽  
Xrd Patterns ◽  
Co Precipitation

ABSTRACTThe microstructure of Ni-Mg-Al mixed oxides obtained by thermal decomposition of hydrotalcite-like compounds synthesized by a co-precipitation method has been studied by using X-ray diffraction (XRD) and atomic resolution transmission electron microscopy (TEM). XRD patterns revealed the formation of NixMg1-xO (x=0÷1), α-Al2O3 and traces of MgAl2O4 and NiAl2O4 phases. The peaks profile analysis indicated a small grain size, microdeformations and partial overlapping of peaks due to phases with different, but similar interplanar spacings. The microdeformations point out the presence of dislocations and the peaks shift associated with the presence of excess vacancies. The use of atomic resolution TEM made it possible to identify the phases, directly observe dislocations and demonstrate the vacancies excess. Atomic resolution TEM is achieved by applying an Exit Wave Reconstruction procedure with 40 low dose images taken at different defocus. The current results suggest that vacancies of metals are predominant in MgO (NiO) crystals and that vacancies of Oxygen are predominant in Al2O3 crystals.

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