Proficient Ni-Zn-Cr Ferrites: Synthesis and Characterization

2012 ◽  
Vol 510-511 ◽  
pp. 343-347
Author(s):  
S. Nasir ◽  
M.A. Malik ◽  
G. Asghar ◽  
G.H. Tariq ◽  
M. Akram ◽  
...  

Ni-Zn ferrite nanoparticles with Cr doping, having the general formula Ni0.5Zn0.5CrxFe2-xO4(x = 0.1, 0.3, 0.5) were prepared by simplified sol-gel method and sintered at 750±5°C. The structural and magnetic properties of the samples sintered at 750±5°C were studied. From X-ray diffraction (XRD) patterns, it was confirmed that the samples have single phase spinel structure. The crystallite size was calculated from the most intense peak (3 1 1) using the Debye Scherrer formula and was found to be in the range of 29-34 nm. The scanning electron microscope images showed that the particle size of the samples were in the range 60-120nm. Quantum design PPMS model 6700 was used to study magnetic properties of these samples. The effect of Cr doping on the magnetic properties was explained on the basis of cations distribution in the crystal structure.


2015 ◽  
Vol 29 (14) ◽  
pp. 1550090 ◽  
Author(s):  
O. Mirzaee ◽  
R. Mohamady ◽  
A. Ghasemi ◽  
Y. Alizad Farzin

Nanostructure of Y-type hexaferrite with composition of Sr 2 Ni 2 Al x/2 Cr x/2 Fe 12-x O 22 (where x are 0, 0.6, 1.2, 1.8, 2.4 and 3) were prepared by sol–gel auto-combustion method. The influence of Al and Cr doping on the structural and magnetic properties has been investigated. The X-ray diffraction (XRD) patterns confirm phase formation of Y-type hexaferrite. The microstructure and morphology of prepared samples were studied by high resolution field emission scanning electron microscope (FESEM) which shows the hexagonal shape for all of the samples. Magnetic properties were characterized using vibrating sample magnetometer (VSM). The magnetic results revealed that by increasing the Al and Cr to the structure, the coercivity was also increased from 840 Oe to 1160 Oe. Moreover it has been shown that with addition of dopants, saturation magnetization (Ms) and remnant magnetization (Mr) were decreased from 39.61 emu/g to 30.11 emu/g and from 17.51 emu/g to 14.62 emu/g, respectively, due to the entrance of nonmagnetic ions into Fe 3+ sites.



2020 ◽  
Vol 10 (03) ◽  
pp. 2050003
Author(s):  
M. R. Hassan ◽  
M. T. Islam ◽  
M. N. I. Khan

In this research, influence of adding Li2CO3 (at 0%, 2%, 4%, 6%) on electrical and magnetic properties of [Formula: see text][Formula: see text]Fe2O4 (with 60% Ni and 40% Mg) ferrite has been studied. The samples are prepared by solid state reaction method and sintered at 1300∘C for 6[Formula: see text]h. X-ray diffraction (XRD) patterns show the samples belong to single-phase cubic structure without any impurity phase. The magnetic properties (saturation magnetization and coercivity) of the samples have been investigated by VSM and found that the higher concentration of Li2CO3 reduces the hysteresis loss. DC resistivity increases with Li2CO3 contents whereas it decreases initially and then becomes constant at lower value with temperature which indicates that the studied samples are semiconductor. The dielectric dispersion occurs at a low-frequency regime and the loss peaks are formed in a higher frequency regime, which are due to the presence of resonance between applied frequency and hopping frequency of charge carriers. Notably, the loss peaks are shifted to the lower frequency with Li2CO3 additions.



2011 ◽  
Vol 335-336 ◽  
pp. 934-939
Author(s):  
Z. F. Zi ◽  
Y. N. Liu ◽  
Q.C. Liu ◽  
Jian Ming Dai ◽  
Yu Ping Sun

Magnetite (Fe3O4) nanobranches were synthesized using an improved solvothermal technique in mixed ethanol and water solvent. Structural and magnetic properties were systematically investigated. X-ray diffraction results showed that the sample was single-phase spinel structure. The results of scanning electronic microscopy exhibited that the grains were regular like-branch with sizes from 3 to 6 μm in length and in diameter between 50 and 200 nm. The composition determined by energy dispersive spectroscopy was very close to the stoichiometry of Fe3O4. The saturation magnetizations (Ms) at 10 and 300 K of the synthesized Fe3O4nanobranches were much lower than the theoretical values. On one hand, it could be explained by obstructive magnetizing along their non-easy magnetic axes by the shape anisotropy of Fe3O4nanobranches, on the other hand, lesserMscan also be understood by the existence of antisite defects.



Author(s):  
Tran Thi Viet Nga

The CoFe2O4/CoFe2/SiO2 nanocomposite particles were synthesized using a sol- gel method and calcination in hydrogen. The magnetic properties and structure of nanocomposite particles calcinated at 600 oC and 900 oC in range of calcination time from 1 h to 4 h were investigated. The phase composition, surface morphology and magnetic properties of the nanocomposites were investigated using X-ray powder diffraction, scanning electron microscopy and vibrating sample magnetometer. The XRD patterns indicate the existence of both CoFe2O4 and CoFe2 phases in the nanocomposite after reducing at 600 oC for 2 h and 3 h. The single phase CoFe2 was obtained after reducing at 900 oC. The average particles size was evenly distributed in the range of 20 nm to 120 nm. The magnetization increases significantly with increasing of reduction temperature.



2013 ◽  
Vol 789 ◽  
pp. 87-92 ◽  
Author(s):  
Dwita Suastiyanti ◽  
Bambang Soegijono ◽  
M. Hikam

The formation of barium hexaferrite, BaFe12O19 single phase with nanosize crystalline is very important to get the best performance especially magnetic properties. The samples were prepared by sol gel method in citric acid-metal nitrates system. Hence the mole ratios of Ba2+/Fe3+ were varied at 1:12 and 1:11.5 with pH of 7 in all cases using ammonia solution. The solution was then heated at 80-90°C for 3 to 4 hours. Then it was kept on a pre-heated oven at 150°C. The samples were then heat treated at 450°C for 24 hours. Sintering process was done at 850°C and 1000°C for 10 hours.Crystallite size was calculated by X-Ray Diffraction (XRD) peaks using scherrer formula. To confirm the formation of a single phase, XRD analyses were done by comparing the sample patterns with standard pattern. The peak shifting of pattern could be seen from XRD pattern using rocking curves at extreme certain 2θ. It was used MPS Magnet Physik EP3 Permagraph L to know magnetic characteristics. This method can produce BaFe12O19 nanosize powder, 22-34 nm for crystallite size and 55.59-78.58 nm for particle size. A little diference in nanosize affects the peak shifting of XRD pattern significantly but shows a little difference in magnetic properties especially for samples at 850°C and 1000°C with mole ratio of 1:12 respectively. The well crystalline powder is formed at mole ratio of 1:11.5 at 850°C since it has the finest particle (55.59 nm) and crystalline (21 nm), the highest remanent magnetization (0.161 T) and the lowest intrinsic coersive (275.8 kA/m). It is also fitting exactly to the standard diffraction pattern with the highest value of best Figure of Merit (FoM), 90%. XRD peak position of this sample is almost same with XRD peak position of another sample with sinter temperature 1000°C at same mole ratio.



2014 ◽  
Vol 631 ◽  
pp. 193-197
Author(s):  
A.M. Escamilla-Pérez ◽  
D.A. Cortés-Hernández ◽  
J.M. Almanza-Robles ◽  
D. Mantovani ◽  
P. Chevallier

Powders of Mg0.4Ca0.6Fe2O4were prepared by sol-gel using ethylene glycol and Mg, Ca and Fe nitrates as starting materials. Those powders were heat treated at different temperatures (300, 400, 500 and 600 °C) for 30 min. The materials obtained were characterized by X-ray diffraction (XRD) and vibrating sample magnetometry (VSM). The Ca-Mg ferrite with the most appropriate magnetic properties was further analyzed by transmission electron microscopy (TEM). The heating capability of the nanoferrites was also tested via magnetic induction. The XRD patterns of these Ca-Mg ferrites showed a cubic inverse spinel structure. Furthermore, neither traces of hematite nor orthorhombic Ca ferrite phases were detected. Moreover, all the Ca-Mg ferrites are superparamagnetic and the particle size distribution of these Ca-Mg magnetic nanoparticles exhibits an average diameter within the range of 10-14 nm. The needed temperature for hyperthermia treatment was achieved at around 12 min.



2012 ◽  
Vol 512-515 ◽  
pp. 1516-1519
Author(s):  
Qing Ma ◽  
Si Qing Shen ◽  
Jian Jun Xie ◽  
Fei Zhong Ma ◽  
Ying Shi ◽  
...  

Compared to phosphors, scintillating films are shown as a better feature for high–resolution display devices with low loss diffusion. Ce 3+ doped lutetium aluminum garnet (Lu3Al5O12, LuAG) scintillating films with different Ce 3+ concentration have been fabricated by Pechini sol–gel processing combined with the spin–coating technique and characterized by X–ray diffraction (XRD) and photoluminescence (PL) under excitation of UV–VIS light. The results of XRD patterns indicated that the specimen under study is a well–crystallized single–phase of cubic structure. Under an excitation of 442nm , it was found that the PL spectra was the typical Ce 3+ emissions located in the 460–650 nm consisting of two emission bands due to the transitions from the lowest 5d excited state (2D) to the 4f ground state of Ce 3+ , which matches well with the sensitivity curve of the Si–photodiode . The luminescent intensity of LuAG: Ce 3+ films varies with the Ce 3+ contents and reaches the maximum at 1.0 mol% doped. With the increase of calcining temperature, the luminescence intensity in the PL spectra of LuAG:Ce 3+ films was found to increased accordingly due to the improved crystallization.



2016 ◽  
Vol 19 (3) ◽  
pp. 5-10
Author(s):  
Quynh Anh Bao Le ◽  
Vu Hoang Nguyen ◽  
Hoang Thi Thuy Tran ◽  
Ha Ky Phuong Huynh

In this research, strontium hexa-ferrite nanoparticles (SrFe12O19) were synthesized by sol-gel method. The crystal structure, morphology and magnetic properties of nanoparticles were investigated using X-ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Vibrating Sample Magnetometer (VSM). The XRD patterns confirmed the formation of single phase M-type hexagonal crystal structure for powders which was calcined above 700oC. The product shows the magnetization of 66 emu/g, which is consistent with pure hexa-ferrite obtained by other methods, and the magnetic coercivity of 6,145 kOe higher than expected for this hexa-ferrite. The powder morphology is composed of aggregates of hexagonal particles with an average particles size of above 100nm.



2021 ◽  
Vol 12 (4) ◽  
pp. 5021-5030

Polycrystalline Ni-Mn-Zn nano-ferrites doped by the fractional amount of Ce3+ ions were fabricated using the sol-gel method. Characterizations of the as-prepared samples were performed by using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), vibrating sample magnetometer (VSM), and dielectric measurements. Rietveld refined XRD patterns revealed the single-phase cubic spinel structure of the samples corresponds to the space group Fd-3m. Minor shifting of peak positions towards lower diffraction angles increases lattice parameter from 8.4105 to 8.4193 Å with the addition of Ce3+ ions. , The surface morphology and homogeneity of the samples were investigated by using SEM and EDAX spectra. Grain size obtained from SEM analysis is found in the range 29 nm to 33 nm with negligible agglomeration. Analysis of EDAX spectra confirms the stoichiometric proportion of the constituents. Substitution of Ce3+ ions shows typical ferromagnetic curves with enhanced saturation magnetization and magneton number from 54 to 63 emu/gm and 2.71 to 3.09 B respectively. Dielectric measurements of the entire samples show the typical behavior of spinel ferrite. The results predict that the samples are best suitable for high-frequency region applications.



2014 ◽  
Vol 664 ◽  
pp. 75-79
Author(s):  
Beh Hoe Guan ◽  
Muhammad Hanif Zahari ◽  
Lee Kean Chuan

This study investigates the influence of calcination temperatures on the magnetic properties of Ni0.5Zn0.5Fe2O4(Ni-Zn) ferrites.Ni-Zn ferrite with the chemical formula Ni0.5Zn0.5Fe2O4was prepared from their respective nitrate salts through the sol-gel method. The resulting ferrites were characterized using X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and vibrating sample magnetometer (VSM). Single phased Ni0.5Zn0.5Fe2O4 was obtained at all calcination temperatures.FESEM Micrographs reveals an increase in the grain size with the increase of the calcination temperature. Consequently, the magnetic saturation of the samples were found to increase with each increase in the calcination temperature where the highest value obtained is 70.58 emu/g for the samples calcined at 1000°C.



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