Structural characteristics, electrical conduction and dielectric properties of gadolinium substituted cobalt ferrite

Nanocrystalline cobalt ferrite powder has been synthesised by citrate precursor and co-precipitation methods. Structural characterization of the samples has been carried out using powder X-ray diffraction, Fourier transform infrared spectroscopy (FT-IR) and field emission scanning electron microscope (FE-SEM). Distribution of cations among the two interstitial sites (tetrahedral and octahedral sites) has been estimated by analysing the powder X-ray diffraction patterns by employing Rietveld refinement technique, and the results reveal the existence of samples as a mixed type spinel with cubic structure. It is observed that the distribution of cations and structural parameters are strongly dependent on synthesis method and annealing temperature. The vibrational modes of the octahedral and tetrahedral metal complex in the sample have been examined using FT-IR in the wave number range of 390 to 750 cm −1 , and it shows an absorption band within this range, which confirms the spinel structure of the sample. The existence of constituents in the sample, i.e., Co, Fe and O has been authenticated using energy dispersive spectrum with the help of a FE-SEM.

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Rietveld analysis of XRD patterns of different sizes of nanocrystalline cobalt ferrite

Influential diamagnetic magnesium (Mg2+) ion substitution in nano-spinel zinc ferrite (ZnFe2O4): Thermal, structural, spectral, optical and physisorption analysis

Nickel Spinel Ferrites: A review

Microwave absorbing properties of ferrites and their composites: A review

Nickel ferrite nanoparticles of very small size were prepared by sol-gel combustion and co-precipitation techniques. At the same annealing temperature sol-gel derived particles had bigger crystallite size. In both methods, crystallite size of the particles increased with annealing temperature. Sol-gel derived nickel ferrite particles were found to be of almost spherical shape and moderate particle size with a narrow size distribution; while co-precipitation derived particles had irregular shape and very small particle size with a wide size distribution. Nickel ferrite particles produced by sol-gel method exhibited more purity. Sol-gel synthesized nanoparticles were found to be of high saturation magnetization and hysteresis. Co-precipitation derived nickel ferrite particles, annealed at 400°C exhibited superparamagnetic nature with small saturation magnetization. Saturation magnetization increased with annealing temperature in both the methods. At the annealing temperature of 600°C, co-precipitation derived particles also became ferrimagnetic.

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Influence of preparation method on structural and magnetic properties of nickel ferrite nanoparticles

Dielectric behavior and AC conductivity of Tb3+ doped Ni0.4Zn0.6Fe2O4 nanoparticles

Effect of Tb3+ substitution on structural, electrical and magnetic properties of sol–gel synthesized nanocrystalline nickel ferrite

Effect of samarium substitution on structural and magnetic properties of magnesium ferrite nanoparticles

A series of nickel–cadmium ferrite, Ni0.9Cd0.1GdxFe2−xO4 (x=0, 0.1, 0.2 and 0.3), was prepared through the sol–gel technique. Samples were characterized using x-ray diffraction (XRD), Fourier transform infrared spectroscopy, a wavelength dispersive x-ray fluorescence spectrometer, a transmission electron microscope and a vibrating sample magnetometer. XRD analysis confirmed the formation of single-phase spinel structure in all the samples. The effect of Gd3+ doping on the crystalline phase, crystallite size and magnetic properties was investigated in detail. Gadolinium doping improved the crystallinity and induced compressive strain in Ni–Cd mixed ferrite. The lattice parameter was observed to increase for minor Gd3+ doping (up to x=0.1); however, further doping resulted in a reduction of the lattice constant. The saturation magnetization decreased and coercivity increased with an increase in gadolinium content.

Binu P. Jacob

Papers

Influence of preparation method on structural and magnetic properties of nickel ferrite nanoparticles

Dielectric behavior and AC conductivity of Tb3+ doped Ni0.4Zn0.6Fe2O4 nanoparticles

Effect of Tb3+ substitution on structural, electrical and magnetic properties of sol–gel synthesized nanocrystalline nickel ferrite

Effect of samarium substitution on structural and magnetic properties of magnesium ferrite nanoparticles

Effect of Gd3+ doping on the structural and magnetic properties of nanocrystalline Ni?Cd mixed ferrite