Citrate Auto-combustion Research Articles

Advanced imaging techniques for characterization of 0.5BaTiO3/0.5Ni0.5Zn0.5Fe2O4 multiferroic nanocomposite

New techniques are used to synthesis and characterize 0.5BaTiO3/0.5Ni0.5Zn0.5Fe2O4; (BTO/NZF) multiferroic nanocomposite. Improved citrate autocombustion preparation technique is used to synthesis ferromagnetic and ferroelectric phases of the investigated nanocomposite. Atomic force microscope (AFM) is one of the important tools for imaging, measuring, and manipulating matter at the nanoscale. AFM is used at different sample areas to confirm the data obtained from scanning electron microscope (SEM) and transmission electron microscope (TEM). Moreover AFM gives 3D visualization for the surface texture and roughness showing the morphology of the two distinguishes phases. The traditional characterizations techniques have been used such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) to identify the formation of the two individual phases separately and to study the chemical composition of the prepared nanocomposite respectively.

Synthesis, characterization and studies on magnetic and electrical properties of LaAlyFe1−yO3 nanomultiferroic

Multiferroic LaAlyFe1−yO3; 0.00⩽y⩽0.20 were successfully synthesized using citrate autocombustion method and their properties were systematically studied. All the samples were crystallized in a perovskite structure. The evaluation of the unit-cell parameters by X-ray diffraction technique revealed that the lattice constants and volume of the unit cell decreased along with increase of Al content, while the Fe–O octahedra became less distorted. The Goldschmidt tolerance factor for the perovskite increases from 0.905 for LaFeO3 to 0.914 for LaAl0.2Fe0.8O3 confirming that the crystal structure is orthorhombic. All the magnetic parameters such as μeff, χM, and magnetization (MRT) decrease as Al content increases, while Néel temperature indicates the highest value (834K) at y=0.1. The magnetic measurements revealed that it has a superparamagnetic behavior with coercive field Hc nearly zero. Dielectric and activation energy results agree well with the other measurements.

Magnetic properties of nanosized MgFe2O4 powders prepared by auto-combustion

Targets were prepared to be used for magnetron sputtering and laser ablation and their microstructural and magnetic properties were investigated. The base material was nanosized MgFe2O4 powder produced by citrate auto-combustion synthesis. The auto-combusted powders were annealed at temperatures in the range 600 - 1000°C in air to study the effect of temperature on thofe formation MgFe2O4. The saturation magnetization Ms was 24.30 emu/g at room temperature.

Magnetic Properties of Nanosized Ba2Mg2Fe12O22 Powders Obtained by Auto-combustion

We studied the magnetic properties of nanosized Ba2Mg2Fe12O22 powder obtained by citrate auto-combustion synthesis. The powder consists of agglomerates with mean crystallite size of 100 nm. The magnetic properties of the powder were investigated at 4.2 K and at room temperature. The values measured of the magnetization M at a magnetic field of 60 kOe are 22.78 emu/g and 30.47 emu/g at room temperature and 4.2 K, respectively. The magnetic phase transition at 183 K is related to the ferromagnetic-to-spiral spin order and is a precondition for this material’s exhibiting multiferroic properties.

Chemical compatibility of Sr-doped La 2CuO 4 cathode material with LSGM solid oxide electrolyte

The chemical reactivity of a novel cathode material for IT-SOFC, La 2 − x Sr xCuO 4 − δ , with the oxide-ion conductor La 0.83Sr 0.17Ga 0.83Mg 0.17O 3 − w is investigated using XRD and ESEM/EDX techniques. La 2 − x Sr xCuO 4 − δ samples (x = 0.1 and 0.2) are prepared by citrate auto-combustion synthesis. The behaviour of mixtures of La 2 − x Sr xCuO 4 − δ cathode material and La 0.83Sr 0.17Ga 0.83Mg 0.17O 3 − w (LSGM) electrolyte (1:1 weight ratio) annealed at 1000 °C for 24–48 h is studied. Peak broadening and shifting in the diffraction patterns are explained as diffusion of cations from one phase to the other; these findings are corroborated by the ESEM/EDX analysis. No diffraction peaks from reaction products are found. These results showed that the use of La 2 − x Sr xCuO 4 − δ (x = 0.1 and 0.2) cathode material in contact with LSGM electrolyte is not advantageous for SOFC application.

Chemical synthesis and structural characterization of the substitution compound LaFe 1− xCu xO 3 ( x = 0–0.40)

LaFe 1− x Cu x O 3 samples with x = 0, 0.05, 0.10, 0.20 and 0.40 were prepared by citrate auto-combustion synthesis; up to x = 0.20 lanthanum ferrites are free from impurity, while for x = 0.40 molar content of copper a small amount of La 2CuO 4 and traces of CuO are present. The crystal structures of LaFe 1− x Cu x O 3, with x = 0.05, 0.10 and 0.20 have been established through the Rietveld method applied to powder X-ray diffraction data. All compounds exhibit the orthorhombic symmetry (space group Pnma) and crystallize in the perovskite-like cell of LaFeO 3, with octahedral sites occupied by a mixture of Fe and Cu and lanthanum atoms 12-fold coordinated. For x = 0–0.20 the oxidation state of iron cations was determined by redox titration to be Fe 3+. The charge compensation required by the substitution of Fe 3+ by Cu 2+ is achieved by the elimination of oxygen atoms. The consistency of the crystal data with the charge compensation mechanism is discussed.

Highly aluminium doped barium and strontium ferrite nanoparticles prepared by citrate auto-combustion synthesis

Aluminium doped barium and strontium hexaferrite nanoparticles BaAl x Fe (12− x) O 19 and SrAl x Fe (12− x) O 19 were synthesised via a sol–gel route using citric acid to complex the ions followed by an auto-combustion reaction. This method shows promise for the synthesis of complex ferrite powders with small particle size. It was found that around half of the iron could be substituted for aluminium in the barium ferrite with structure retention, whereas strontium aluminium ferrites could be produced with any aluminium content including total substitution of the iron. All synthesised materials consisted of particles smaller than 1 μm, which is the size of a single magnetic domain, and various doping levels were achieved with the final elemental composition being within the bounds of experimental error. The materials show structural and morphological changes as they move from iron to aluminium ferrites. Such materials may be promising for imaging applications.