Influence of Ba/Fe mole ratios on magnetic properties, crystallite size and shifting of X-ray diffraction peaks of nanocrystalline BaFe[sub 12]O[sub 19] powder, prepared by sol gel auto combu

Author(s):  
Dwita Suastiyanti ◽  
Arif Sudarmaji ◽  
Bambang Soegijono
2020 ◽  
Vol 43 (1) ◽  
pp. 26-42 ◽  
Author(s):  
Zahra Hajian Karahroudi ◽  
Kambiz Hedayati ◽  
Mojtaba Goodarzi

AbstractThis study presents a preparation of SrFe12O19– SrTiO3 nanocomposite synthesis via the green auto-combustion method. At first, SrFe12O19 nanoparticles were synthesized as a core and then, SrTiO3 nanoparticles were prepared as a shell for it to manufacture SrFe12O19–SrTiO3 nanocomposite. A novel sol-gel auto-combustion green synthesis method has been used with lemon juice as a capping agent. The prepared SrFe12O19–SrTiO3 nanocomposites were characterized by using several techniques to characterize their structural, morphological and magnetic properties. The crystal structures of the nanocomposite were investigated via X-ray diffraction (XRD). The morphology of SrFe12O19– SrTiO3 nanocomposite was studied by using a scanning electron microscope (SEM). The elemental composition of the materials was analyzed by an energy-dispersive X-ray (EDX). Magnetic properties and hysteresis loop of nanopowder were characterized via vibrating sample magnetometer (VSM) in the room temperature. Fourier transform infrared spectroscopy (FTIR) spectra of the samples showed the molecular bands of nanoparticles. Also, the photocatalytic behavior of nanocomposites has been checked by the degradation of azo dyes under irradiation of ultraviolet light.


2011 ◽  
Vol 268-270 ◽  
pp. 356-359 ◽  
Author(s):  
Wen Song Lin ◽  
C. H. Wen ◽  
Liang He

Mn, Fe doped ZnO powders (Zn0.95-xMnxFe0.05O2, x≤0.05) were synthesized by an ameliorated sol-gel method, using Zn(CH3COO)2, Mn(CH3COO)2and FeCl2as the raw materials, with the addition of vitamin C as a kind of chemical reducer. The resulting powder was subsequently compacted under pressure of 10 MPa at the temperature of 873K in vacuum. The crystal structure and magnetic properties of Zn0.95-xMnxFe0.05O2powder and bulk samples have been investigated by X-ray diffraction (XRD) and vibrating sample magnetometer (VSM). X-ray photoelectron spectroscopy (XPS) was used to study chemical valence of manganese, iron and zinc in the samples. The x-ray diffraction (XRD) results showed that Zn0.95-xMnxFe0.05O (x≤0.05) samples were single phase with the ZnO-like wurtzite structure. No secondary phase was found in the XRD spectrum. X-ray photoelectron spectroscopy (XPS) showed that Fe and Mn existed in Zn0.95-xMnxFe0.05O2samples in Fe2+and Mn2+states. The results of VSM experiment proved the room temperature ferromagnetic properties (RTFP) of Mn, Fe co-doped ZnO samples.


2006 ◽  
Vol 118 ◽  
pp. 53-58
Author(s):  
Elisabeth Meijer ◽  
Nicholas Armstrong ◽  
Wing Yiu Yeung

This study is to investigate the crystallite development in nanostructured aluminium using x-ray line broadening analysis. Nanostructured aluminium was produced by equal channel angular extrusion at room temperature to a total deformation strain of ~17. Samples of the extruded metal were then heat treated at temperatures up to 300oC. High order diffraction peaks were obtained using Mo radiation and the integral breadth was determined. It was found that as the annealing temperature increased, the integral breadth of the peak reflections decreased. By establishing the modified Williamson-Hall plots (integral breadth vs contract factor) after instrumental correction, it was determined that the crystallite size of the metal was maintained ~80 nm at 100oC. As the annealing temperature increased to 200oC, the crystallite size increased to ~118 nm. With increasing annealing temperature, the hardness of the metal decreased from ~60 HV to ~45 HV.


2002 ◽  
Vol 753 ◽  
Author(s):  
I. Baker ◽  
R. G. Quiller ◽  
M. Robson ◽  
D. Wu

ABSTRACTPowders of near-equiatomic Fe and Co were mechanically milled with additions of Zr, C, Ni, Cu and/or B for 60 hr using stainless steel balls in a Svegari attritor operated at 1300 r.p.m. under argon. The milled powders were examined before and after annealing at 600 °C. The morphologies and sizes of the powders were examined using a scanning electron microscope. The grain sizes were characterized from the widths of X-ray diffraction peaks obtained using a computer-controlled x-ray diffractometer and the lattice parameters were determined. The resulting magnetic properties were measured using a vibrating sample magnetometer.


1998 ◽  
Vol 13 (2) ◽  
pp. 451-456 ◽  
Author(s):  
C. Vázquez-Vázquez ◽  
P. Kögerler ◽  
M. A. López-Quintela ◽  
R. D. Sánchez ◽  
J. Rivas

The study of submicroscopic particles in already known systems has resulted in a renewed interest due to the large differences found in their properties when the particle size is reduced, and because of possible new technological applications. In this work we report the preparation of LaFeO3 particles by the sol-gel route, starting from a solution of the corresponding metallic nitrates and using urea as gelificant agent. Gels were decomposed at 200 °C and calcined 3 h at several temperatures, T, in the range 250–1000 °C. The samples were structurally characterized by x-ray diffraction (XRD) showing that the orthoferrite crystallizes at T as low as 315 °C. From the x-ray diffraction peak broadening, the particle size was determined. The size increases from 60 to 300 nm as the calcination T increases. Infrared spectroscopy was used to characterize gels and calcined samples. From these studies a mechanism for the gel formation is proposed. Study of the magnetic properties of LaFeO3 particles shows the presence of a ferromagnetic component which diminishes as the calcination temperature increases, vanishing at T = 1000 °C.


2012 ◽  
Vol 26 (26) ◽  
pp. 1250141 ◽  
Author(s):  
Y. B. HAN ◽  
J. SHA ◽  
L. N. SUN ◽  
Q. TANG ◽  
Q. LU ◽  
...  

Sm (Co or/and Zn) substituted nanocrystalline barium hexaferrites were synthesized by the sol–gel auto-combustion process, then X-ray diffraction (XRD) and vibrating sample magnetometer (VSM) were used to characterize and discuss the phase composition and the magnetic properties of the as-prepared barium hexaferrites. All results showed that the phase composition and magnetic properties were closely related to the doping elements and x. Owing to hyperfine field, canting spin, magnetic dilution and impurity phases, the saturation magnetization (Ms) of all samples increased firstly, and then decreased. Considering the crystallization, the magnetocrystalline anisotropy and the ions occupancy, the doping elements and x critically affected the coercivity (Hc). Compared the magnetic properties of all the samples, it is concluded that Zn 2+ and Co 2+ influenced each other and Zn 2+ occupied 4f2 sites prior to Co 2+, which led to the increase of Ms and the decrease of Hc.


2003 ◽  
Vol 36 (6) ◽  
pp. 1411-1416 ◽  
Author(s):  
Z. K. Heiba ◽  
Y. Akin ◽  
W. Sigmund ◽  
Y. S. Hascicek

Polycrystalline samples of (Eu1−xYbx)2O3(x= 0.0, 0.1, 0.2, 0.5, 0.8, 0.9 and 1.0) were synthesized by a sol–gel process. X-ray diffraction data were collected and the crystal structures were refined by the Rietveld method. All samples are found to have the same crystal system and formed solid solutions over the whole range ofx. The lattice parameters are found to vary linearly with the compositionx. The cationic distribution over the two non-equivalent sites 8band 24dof the space group Ia{\bar 3} is found to be random in the range 0.0 <x≤ 0.5 and preferential in the range 0.5 <x≤ 1.0. Replacing Eu3+and Yb3+by each other introduces slight changes in the atomic coordinates. Crystallite size and microstrain analysis are performed on single and multiple orders for each sample using profile fitting and the Warren–Averbach method. The obtained values of microstrain are correlated with the distribution of the rare earth (RE) ions over the two cationic sites of the structure. The average crystallite size ranges from 35 to 96 nm and the mean-square strain from 0.052 to 0.225 × 10−2.


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.


2010 ◽  
Vol 09 (03) ◽  
pp. 215-223 ◽  
Author(s):  
A. A. EL-MELIGI ◽  
A. M. AL-SAIE ◽  
H. AL-BUFLASA ◽  
M. BOUOUDINA

The crystalline semiconductor material (MnPS3) has interlayer d-spacing gap of 6.4 Å. The main advantage of this gap is the ability to accommodate organic and inorganic compounds. Pyridine was intercalated in the MnPS3 interlayer gap under specific conditions. Four phases (d-spacing = 12.48 Å, 10.8 Å, 9.7 Å and 7.3 Å) were observed and the corresponding lattice expansions were determined, 5.8 Å, 4.4 Å, 3.3 Å and 1 Å, respectively. X-ray diffraction patterns of the samples after the experiment were stopped to reveal the presence of three phases together. The phase transformation occurred for the aforementioned phases. The crystallite size of certain phases is within nanorange. The magnetic properties of the materials are affected by the phase transformation. Complete intercalation was confirmed by the XRD and infrared (IR) measurements.


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