Cation distribution of Ni 0.5 Zn 0.5 Fe 2 O 4 nanoparticles (original) (raw)
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Structural analysis and cations distribution of nanocrystalline Ni1−Zn Fe1.7Ga0.3O4
Journal of Alloys and Compounds, 2015
Nanostructured Ni 1-x Zn x Fe 1.7 Ga 0.3 O 4 , with x=0.0, 0.1, 0.2, 0.3, 0.4 and 0.5 were prepared by citrate method and were investigated using x-ray diffraction and Mossbauer spectroscopy. The structure characterized using X-ray powder diffraction and Rietveld method showed that upon increasing Zn 2+ content, the lattice parameter gradually increases from a=8.3493 to 8.390 Ǻ and also the crystallite size increases from 4 to 8 nm for x=0.0 and x=0.5 respectively. Furthermore, the Mössbauer spectra, measured at 20 K showing spinel magnetic ordering in all the samples, whereas at room temperature, are superposition of collapsing broadened sextet and doublet because of the dependency of particle size. The Cation distribution was estimated from the analysis of the Mossbauer spectra as well as Bertaut method, and then confirmed by Rietveld analysis. The results showed that both Zn and Ga ions exclusively occupy the A-site while Ni and Fe ions are distributed over the A-and B-sites.
Synthesis of Nanocrystalline Ni 0.5 Zn 0.5 Fe 2 O 4 by Aerosol Route and Its Characterization
Hyperfine Interactions, 2004
Nano-size particles of Ni 0.5 Zn 0.5 Fe 2 O 4 ferrite were prepared through aerosol route. The solutions of iron, nickel and zinc nitrates were mixed in stoichiometric proportion, passed through a pneumatic nebulizer, to get very fine mist (aerosols), and a furnace at ∼600 • C in air atmosphere. Through various events in succession, metal atoms form ferrite in air. The average particle size was found to be 16±6 nm which increased to 80±8 nm after annealing at 1000 • C. The room-temperature magnetic moment of the sample as obtained and after annealing it at various temperatures indicate that the saturation magnetization increases from 1.80 to 72.8 emu/g, while remanent magnetization increases from 0.28 to 25.0 emu/g. Mössbauer spectrum of the sample at room temperature exhibited a doublet with δ(Fe) = 0.33 mm s −1 and E Q = 0.78 mm s −1 suggesting superparamagnetic nature. However, after annealing at 1000 • C this doublet got converted into two magnetic sextets with B = 52.4 T and 49.0 T suggesting increase in particle size on annealing. These observations are in conformity with Transmission Electron Microscope (TEM) and X-Ray Diffraction (XRD) results that the particle size increases after annealing the sample at higher temperatures.
Ni 0.5 M 0.5 Fe 2 O 4 (M = Co, Cu) ferrite nanoparticles were synthesized using citrate precursor method. The citrate precursor was annealed at temperatures 400 o C, 450 o C, 500 o C and 550 o C. The annealed powders were characterized using X-ray diffractometer (XRD) and vibrating sample magnetometer (VSM). Observed XRD data was further analyzed using Rietveld analysis which showed that particles annealed at temperatures upto 450 o C display cubic spinel structure while the particles formed at temperature higher than 450 o C display a tetragonal spinel structure. Sharp changes were observed in particle size, lattice constant, magnetization and retentivity in the range 450-500 o C temperature suggesting that nucleation/growth mechanism is different at temperatures above and below a critical temperature in this range.
The calcinations temperature is one of the important process parameter which influences the changes of magnetic properties in ferrites. This study provide better understanding of the influence of calcination temperatures on the magnetic properties of Nickel Zinc ferrite consequently enable to tailor the magnetic properties of Nickel Zinc ferrite for specific application. Magnetic nanoparticles of Nickel Zinc ferritewere synthesized by sol-gel technique. Their crystallite size and the influence of calcinations temperature on magnetic properties were investigated by using X-Ray Diffraction (XRD) and Vibrating Sample Magnetometer (VSM). XRD results showed that the crystallization of the Nickel Zinc ferriteincreased as the calcination temperature increased. The results showed that single phase of Nickel Zinc ferritesamples can be obtained at various calcination temperatures from 800 to 1100°C. All Nickel Zinc ferritesamples exhibited ferrimagnetic behavior. VSM results showed that the saturation magnetization and coercivity values strongly influenced by the calcination temperature.
Cation distribution in nanosized Ni–Zn ferrites
Journal of Applied Physics, 2004
Nanoparticles of Ni 1Ϫx Zn x Fe 2 O 4 (xϭ0.0, 0.25, 0.50, 0.75, and 1.0͒ in the size range of 6-12 nm have been synthesized by chemical precipitation followed by hydrothermal treatment. A strong correlation between the particle size and the zinc concentration has been identified. Mössbauer studies on these systems show that the cation distribution not only depends on the particle size but also on the preparation route. There are indications that in the present nanophase samples Fe occupies more tetrahedral sites as compared to the normal occupancy in the spinel ferrite structure. The occupancy returns to normal values after heat treatment at 1000°C. Low-temperature Mössbauer studies indicate a significant amount of deviation of cation distribution from their bulk preferences.
Nickel zinc ferrite nanoparticles Ni x Zn 1 À x Fe 2 O 4 (x =0.1, 0.3, 0.5) have been synthesized by a chemical co-precipitation method. The samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, electron paramagnetic resonance, dc magnetization and ac susceptibility measurements. The X-ray diffraction patterns confirm the synthesis of single crystalline Ni x Zn 1 À x Fe 2 O 4 nanoparticles. The lattice parameter decreases with increase in Ni content resulting in a reduction in lattice strain. Similarly crystallite size increases with the concentration of Ni. The magnetic measurements show the superparamagnetic nature of the samples for x= 0.1 and 0.3 whereas for x= 0.5 the material is ferromagnetic. The saturation magnetization is 23.95 emu/g and increases with increase in Ni content. The superparamagnetic nature of the samples is supported by the EPR and ac susceptibility measurement studies. The blocking temperature increases with Ni concentration. The increase in blocking temperature is explained by the redistribution of the cations on tetrahedral (A) and octahedral (B) sites.
Finite size effect on Ni doped nanocrystalline Ni x Zn 1− x Fe 2 O 4 (0.1≤ x≤ 0.5)
Nanocrystalline nickel ferrite with different concentration of Ni and Zn (Ni x Zn 1 − x Fe 2 O 4 where x = 0.1, 0.3, 0.5) were synthesized using chemical co-precipitation method. The effect of doping ion concentration on physical properties like crystalline phase, crystallite size, particle size, and saturation magnetization are investigated. The X-ray diffraction pattern confirms the synthesis of single crystalline Ni x Zn 1 − x Fe 2 O 4 nanoparticles. The lattice parameter decreases with increase Ni content resulting in reduction of lattice strain. HRTEM images revealed that the as-prepared nanoparticles were crystalline with particle size distribution in 10-30 nm range. The saturation magnetization show the superparamagnetic nature of sample for x = 0.1 and x = 0.3 whereas for x = 0.5, the material is ferromagnetic. The saturation magnetization value is 23.95 emu/gm for Ni 0.1 Zn 0.9 Fe 2 O 4 sample and it increases with increase in Ni content.
Chinese Journal of Chemical Physics, 2008
Ferrites having general formula Ni 1−x ZnxFe 2 O 4 with x=0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, and 0.7 were prepared by wet chemical co-precipitation method. The structural and magnetic properties were studied by means of X-ray diffraction, magnetization, and AC susceptibility measurements. The X-ray analysis confirmed the single-phase formation of the samples. The lattice parameter obtained from XRD data was found to increase with Zn content x. The cation distribution was studied by X-ray intensity ratio calculations. Magnetization results exhibit collinear ferrimagnetic structure for x≤0.4, and which changes to non-collinear for x >0.4. Curie temperature T C obtained from AC susceptibility data decreases with increasing x.