Investigation of Nanostructure and Magnetic Properties of Nanocrystalline NiZnCu Ferrites Synthesized by Sol-Gel Method

2015 ◽  
Vol 754-755 ◽  
pp. 1169-1174 ◽  
Author(s):  
Prengki Pransisco ◽  
Afza Shafie ◽  
Beh Hoe Guan

Nanocrystalline material of ferrites with composition Ni0.5Zn0.35Cu0.15Fe2O4was successfully synthesized by sol-gel method. This paper investigates nanostructure and magnetic properties of nanocrystaline material Ni0.5Zn0.35Cu0.15Fe2O4.Crystallite size, intensity,d-spacing and lattice parameters of material were investigated by using X-Ray diffractometer (XRD). While nanostructure, size, shape, surface morphology and topography of Ni0.5Zn0.35Cu0.15Fe2O4were examined by variable pressure field emission scanning electron microscope (VP-FESEM) SUPRA 55VP. Magnetic properties was investigated using vibrating sample magnetometer (VSM). According to thermo gravimetric analysis (TGA) result, it was found that after temperature 600oC there is no more weight loss detected and it was considered as minimum calcination temperature. XRD result shows that the samples is in single-phase cubic spinel structure. Crystallite size of the material is in range of 42.3-163.7nm. Highest intensity was 88.89 arb.units at highest calcination temperature 900oC. The value of d-spacing and FWHM decrease with increasing calcination temperature. Lattice paramenters decrease in the range of 8.4040-8.2458oA. VP-FESEM analysis shows that grain size increase by increasing calcination temperature. Grain size of the material is in the range of 47.6-506.9nm with cubic structure of the Ni0.5Zn0.35Cu0.15Fe2O4.VSM result shows that the highest value of magnetic saturation was at 152.8emu/g. The best value of coercive force (Hc) was in 31.8Oe and magnetic remanence (Mr) was in 2.6emu/g.

Author(s):  
T. Pikula ◽  
T. Szumiata ◽  
K. Siedliska ◽  
V. I. Mitsiuk ◽  
R. Panek ◽  
...  

AbstractIn this work, BiFeO3 powders were synthesized by a sol–gel method. The influence of annealing temperature on the structure and magnetic properties of the samples has been discussed. X-ray diffraction studies showed that the purest phase was formed in the temperature range of 400 °C to 550 °C and the samples annealed at a temperature below 550 °C were of nanocrystalline character. Mössbauer spectroscopy and magnetization measurements were used as complementary methods to investigate the magnetic state of the samples. In particular, the appearance of weak ferromagnetic properties, significant growth of magnetization, and spin-glass-like behavior were observed along with the drop of average grain size. Mössbauer spectra were fitted by the model assuming cycloidal modulation of spins arrangement and properties of the spin cycloid were determined and analyzed. Most importantly, it was proved that the spin cycloid does not disappear even in the case of the samples with a particle size well below the cycloid modulation period λ = 62 nm. Furthermore, the cycloid becomes more anharmonic as the grain size decreases. The possible origination of weak ferromagnetism of the nanocrystalline samples has also been discussed.


2010 ◽  
Vol 13 (1-2) ◽  
pp. 85 ◽  
Author(s):  
S. Manocha ◽  
Parth Joshi ◽  
Bhavini Patel ◽  
L.M. Manocha

<p>Hydroxyapatite (HAp) is a unique material having high adsorption capacity of heavy metals, high ion exchange capacity, high biological compatibility, low water solubility, high stability under reducing and oxidizing conditions, availability and low cost. Hydroxyapatite nanoparticles have been synthesized by Sol-gel method using Calcium nitrate tetrahydrate [Ca(NO<sub>3</sub>)<sub>2</sub>•4H<sub>2</sub>O] and Phosphorus pentaoxide (P<sub>2</sub>O<sub>5</sub>) as starting reactants. The addition of Phosphorus pentaoxide to Calcium nitrate tetrahydrate was carried out slowly with simultaneous stirring. After addition, solution was aged for 10 minutes for maturation. The precipitate was dried at 80 °C overnight and further heat treated at 550 °C for 2 hours. The dried and calcined particles were characterized by X-ray diffractometry, Fourier transform infra-red spectroscopy and Thermo gravimetric analysis. The particle size and morphology were studied using transmission electron microscopy. TEM examination of the treated powders displayed particles of polygon morphology with dimensions 20-50 nm in length. The FT-IR spectra for sample confirmed the formation of hydroxyapatite.</p>


Author(s):  
Guo-Bin Jung ◽  
Ting-Chu Jao ◽  
Chia-Chen Yeh ◽  
Ming-Hsien Huang ◽  
Wang-Shen Su

A series of Y0.2ZrxCe0.8−xO1.9 compounds (0 ≤ x ≤ 0.6) had been prepared by the modified sol-gel method and characterized by powder X-ray diffraction, thermo-gravimetric analysis, four-probe resistivity, and Vickers’s hardness studies. The gels from co-precipitation were treated with heated 1-octanol. All of the samples showed fluoride structure after calcined at 600 °C. Sintering the powders of Y0.2Ce0.8O1.9 and Y0.2Zr0.6Ce0.2O1.9 at 1300 °C gave the relative density of 95.8% and 99%, respectively. 99% relative density could be obtained for all samples after sintering at 1500 °C. This study showed a much more improved result than that of the previous reports. The hardness was 13.7 GPa for the Y0.2Zr0.6Ce0.2O1.9 pellet, which was twice greater than that for Y0.2Ce0.8O1.9 (7.1 GPa). Therefore, the mechanical properties could be improved by the addition of ZrO2 to Y0.2ZrxCe0.8−xO1.9. At 800 °C, the electrical conductivity of Y0.2Ce0.8O1.9 and Y0.2Zr0.6Ce0.2O1.9 were 3.3 × 10−2 S/cm and 5.5 × 10−3 S/cm, respectively. The conductivity was decreased by the addition of ZrO2 to Y0.2Ce0.8O1.9. It showed that the conductivity and hardness of Y0.2Zr0.2Ce0.6O1.9 were 1.2 × 10−2 S/cm and 9.6 GPa, respectively, at 800 °C and could be a better electrolyte candidate for “intermediate-temperature” unitized regenerative solid oxide fuel cells.


2014 ◽  
Vol 936 ◽  
pp. 238-242
Author(s):  
Yi Bao ◽  
Wei Hui Jiang ◽  
Guo Feng ◽  
Jian Min Liu ◽  
Qian Wu

Aluminum titanate (Al2TiO5) film was prepared via sol-gel method at low temperature, using ethyl acetoacetate and anhydrous citric acid as compound chelating agent, tetrabutyl titanate (Ti (OC4H9)4) and aluminum chloride (AlCl3.6H2O) as precursors, ethanol as solvent. The phase transformation of Al2TiO5 xerogel during heat treatment, the effect of different chelating agents on the synthesis of Al2TiO5, and the phase composition and morphology of film were investigated by means of differential thermal and thermo gravimetric analysis (DTA-TG), X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR) and field-emission scanning electron microscopy (FE-SEM). The results demonstrate that Al2TiO5 can be synthesized at 750 °C by using compound chelating agent, rather than single chelating agent. Compound chelating agent contributes to the formation of Al-O-Ti heterogeneous bond, which is the key to preparing Al2TiO5 at low temperature. High quality Al2TiO5 film could be coated on the SiC substract at 750°C.


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.


2013 ◽  
Vol 756 ◽  
pp. 91-98 ◽  
Author(s):  
Ftema W. Aldbea ◽  
Noor Bahyah Ibrahim ◽  
Mustafa Hj. Abdullah

Terbium –substituted yttrium iron garnet (Tb1.5Y1.5Fe5O12) films nanoparticles were successfully prepared by a sol-gel method. The films were deposited on the quartz substrate using spin coating technique. To study effect of annealing temperature, the annealing process was executed at 700, 800 and 900 °C in air for 2 hours. The X-ray diffraction (XRD) proved that the pure phase of garnet structure was detected for the film annealed at 900 °C. The lattice parameter increased with the increment of annealing temperature and the highest value of 12.35 Å was obtained at 900 °C. Field Emission Scanning Electron Microscope (FE-SEM) results showed that the particle size increased from 43nm to 56nm as annealing temperature increased from 700 to 900°C. The film’s thickness also affected by increasing of annealing temperature and become thin at 900 °C due to densification process occurred at high annealing temperature. The elemental compositions of the Tb1.5Y1.5Fe5O12 film were detected using an Energy Dispersive X-raySpectroscopy (EDX). Magnetic properties at room temperature were measured using a Vibrating Sample Magnetometer (VSM).The saturation magnetization Ms increased with the annealingtemperature and showed a high value of 104emu/cm3, but the coercivity Hc of the film was decreased due to the increment of the particle size. Normal 0 21 false false false MS X-NONE X-NONE MicrosoftInternetExplorer4 Terbium –substituted yttrium iron garnet (Tb1.5Y1.5Fe5O12) films nanoparticles were successfully prepared by a sol-gel method. The films were deposited on the quartz substrate using spin coating technique. To study effect of annealing temperature, the annealing process was executed at 700, 800 and 900°C in air for 2 hours. The X-ray diffraction (XRD) proved that the pure phase of garnet structure was detected for the film annealed at 900 °C. The lattice parameter increased with the increment of annealing temperature and the highest value of 12.35 Å was obtained at 900 °C. Field Emission Scanning Electron Microscope (FE-SEM) results showed that the particle size increased from 43nm to 56nm as annealing temperature increased from 700 to 900 °C. The film’s thickness also affected by increasing of annealing temperature and become thin at 900 °C due to densification process occurred at high annealing temperature. The elemental compositions of the Tb1.5Y1.5Fe5O12 film were detected using an Energy Dispersive X-ray Spectroscopy (EDX). Magnetic properties at room temperature were measured using a Vibrating Sample Magnetometer (VSM).The saturation magnetization Ms increased with the annealing temperature and showed a high value of 104emu/cm3, but the coercivity Hc of the film was decreased due to the increment of the particle size. st1\:*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}


2011 ◽  
Vol 110 (8) ◽  
pp. 083901 ◽  
Author(s):  
K. Nomura ◽  
J. Okabayashi ◽  
K. Okamura ◽  
Y. Yamada

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