Effect of Li substitution on the magnetic properties of LixMg0.40Ni0.60-2xFe2+xO4 ferrites (original) (raw)
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Structural and Magnetization Behaviors of Ni Substituted Li-Mg Ferrites
Magnetization behaviors of Ni-substituted Li x Mg 0.5 Ni 0.5-2x Fe 2+x O 4 ferrites, where x = 0.25, 0.20, 0.15, 0.10 and 0.00 synthesized by standard ceramic technology sintered at 1300°C in air for 5 hours has been presented in the present study. The bulk density and lattice constants of the samples found to be decreased with the increase in the Ni-content for the x values from 0.25 to 0.00. DC electrical resistivity has found to show highest magnitude at room temperature and decreases with further increase in temperature. Magnetization of the samples has been measured as a function of the field using hysteresis loop tracer at 30°C. It was observed that addition of nickel in polycrystalline Li-Mg ferrites plays an important role in modification of structural and magnetization characteristics.
Influence of Li substitution on structural and magnetic properties of LixNi0.2Mg0.8−2xFe2+xO4
Materials Chemistry and Physics, 2012
The structural and magnetic properties of polycrystalline Li x Ni 0.2 Mg 0.8−2x Fe 2+x O 4 (where x = 0.00, 0.10, 0.20, 0.30 and 0.40) synthesized by the conventional solid state reaction method is reported. The X-ray diffraction patterns reveal that these compositions are single phase having spinel structure. Lattice constants of the compositions are found to decrease with increasing Li content. The bulk density and average grain diameter are observed to increase with increasing Li content for a fixed sintering temperature and also increase with increasing sintering temperature for a fixed chemical composition. As sintering temperature goes higher, porosity decreases and real part of the initial permeability increases. Increase of initial permeability is more than double (66) compared to parent composition (31). The saturation magnetization at room temperature is found to increase with increasing Li content due to the modification of cations distributions. The observed features of lattice constant, density, microstructure, initial permeability and DC magnetization of the investigated compositions are explained.
Materials Letters, 2002
The structural and bulk magnetic properties of mixed spinel ferrite system Mg x Al 2x Li 0.5(1 À x) Fe 2.5(1 À x) O 4 (x = 0.0, 0.1, 0.2, 0.3, 0.4 and 0.5) have been investigated by means of X-ray diffraction, magnetization and a.c. susceptibility measurements. The cation distribution determined through X-ray data are supported by the magnetization and susceptibility measurements. The study has revealed the strong octahedral site preference of Li + and Al 3 + as compared to Mg 2 +. It is also found that the magnetic ordering in the system is of collinear type and the variation of magnetization can be explained on the basis of Neel's collinear spin model. The Neel temperatures calculated theoretically are in good agreement to those deduced experimentally.
Analysis of Magnetic Properties of Substituted Li Ferrites
IEEE Transactions on Magnetics, 2010
Substituted Li ferrites with chemical composition Li 0 5+0 5 0 5 Fe 2 5 1 5 0 5 Ti Zn O 4 , where = 020 and = 0 35 0 45 0 55 with additions of 0.005 Bi 2 O 3 and 0.05 MnO 2 were synthesized by ceramic method and from solutions of metallic salts and citric acid. The intrinsic and extrinsic magnetic properties were measured and are discussed from the point of view of the substituting element content as well as the grain size. The magnetic polarization, Curie temperature, saturation induction, susceptibility, and coercivity were measured and the Mössbauer spectra of certain samples have been analyzed. According to the requirements in specific applications, the properties of LiZnTi ferrite can be improved by means of proper substitution of selected ions and processing technology.
Journal of Magnetism and Magnetic Materials, 2017
A series of La-substituted Manganese-Zinc based ferrites of nominal composition Mg Zn La Fe 0.5 0.5 2x 2-O for x = 0.00-0.05 in steps of 0.01 was produced by conventional ceramic technique. From X-Ray diffraction 2x 4 patterns, all samples showed single cubic spinel structure as a main phase along with small traces of second phase (LaFeO). The Lattice constant shows a decreasing trend with the substitution of lanthanum. This may 3 be due to large difference in the ionic radii of Fe and La ions. La ions may not enter into the spinel lattice 3+ 3+ 3+ due to large ionic radius. During the sintering process, some of the La ions diffused in to the grain boundaries 3+ and can form an insulating ultra thin layer around the grains. This causes the shrinkage of the spinel lattice and hence lattice constant decreases. Dc resistivity and activation energies showed increasing trend with increasing La contents. The temperature dependent resistivity and activation energy decreases with increasing temperature. The structural, physical and electrical properties of La-substituted Manganese-Zinc based ferrites are discussed in the current paper.
Magnetic, Dielectric and Electrical Properties of Lithium-Magnesium Ferrites
A series of polycrystalline spinel type ferrites with composition Li x Mg 0.5 Ni 0.5-2x Fe 2+x O 4 , where x = 0.00 to 0.25 in steps of 0.05, have been prepared by standard double sintering method sintered at temperature 1200º C in air for 6 hours. In this work, investigations have been carried out by the measurements of X-ray diffraction (XRD), Curie temperature, permeability, loss tangent, Qfactor, dielectric constant and ac electrical resistivity of the samples. Some measurements have been done at room temperature while other measurements have been done as a function of temperature and as a function of frequency in the range from 1 kHz to 500 kHz. Curie temperature, the real part of initial permeability (µ i ʹ), the loss tangent (tanδ), and the Q-factor have been found to be decreased with the increase of Ni-content of Li x Mg 0.5 Ni 0.5-2x Fe 2+x O 4 ferrites. The frequency characteristic of dielectric constant and AC resistivity decreases with the increase in frequency and increases with the increase in Ni-content.
Structural and magnetic properties of Al substituted Li 0.8 Ni 0.1 Zn 0.5 Al x Fe 2-x O 4 ferrites (x=0.0-0.40 in steps of 0.10) prepared by solid state reaction technique have been investigated. Characterization and phase identification of the samples were performed by X-ray diffraction (XRD) technique. The formation of cubic spinel structure without any secondary phase was confirmed by X-ray diffraction analysis. Lattice constant of the compositions decreased with the addition of Al content obeying Vegard's law. The average crystallite size of the samples calculated using Debye-Scherrer equation varied in the range of 19 nm-73 nm. Also, theoretical and bulk density decreased with the substitution of Al content. Besides, porosity showed opposite trend. The real part of initial permeability of the samples decreased the increase in Al content due to replacement of Fe 3+ ions by Al 3+ ions which prefer B-(octahedral) to A-(tetrahedral) sites in the AB 2 O 4 spinel type ferrites. The higher resonance frequencies were observed with the increase in Al content. The doping of Al 3+ influences magnetic parameters due to modification of the cation distribution.
Comparative study of structural and magnetic properties of Cobalt, Lithium and Tin Ferrite
We have prepared nano particles of Cobalt Ferrite CoFe 2 O 4 , Lithium Ferrite LiFe 5 O 8 and Tin Ferrite SnFe 2 O 4 with the help of citrate precursor method. Selection of lithium ferrite was done in order to detect any difference in properties due to different size. Their structural and magnetic properties were studied with the help of X-Ray diffractometer and vibrating sample magnetometer. All the samples were annealed at high temperature (450 0 C – 650 0 C), to reduce the chances of obtaining superparamagnetism. On increasing the temperature sharp rise in particle size of Tin ferrite was seen but in lithium ferrite and Tin ferrite, this was not significant. In the context of magnetic properties, the saturation magnetization was observed to be nearly constant with temperature in case of tin and lithium ferrite. The coercivity of Tin and Lithium ferrite was nearly independent of temperature but in cobalt ferrite there was sharp decrease in coercivity with temperature. We expect that present work will help in synthesis of ferrites by a low cost route making analysis of properties easier.
Journal of Magnetism and Magnetic Materials, 2010
Nanoparticles of Li 0.1 (Ni 1 À x Zn x) 0.8 Fe 2.1 O 4 with x varying from 0.0 to 1.0 were prepared by chemical coprecipitation method. A part of these samples was sintered at 1200 1C for 2 h to obtain bulk samples via increase in particle sizes; the other part was left as-prepared. Structural and magnetic properties comparison studies were carried out between the as-prepared nanoparticle samples and their bulk counterparts. The X-ray diffraction and infrared spectroscopy were used to characterize the samples. The XRD pattern of the samples provides evidence of single phase formation of spinel structure with cubic symmetry. The lattice constant, and X-ray density were calculated from the XRD data. The density of the samples was measured and consequently the porosity was calculated too. In the present work, the effect of nano-structured particle size and Zn concentration on parameters such as bond length and vibration frequency are discussed with the help of the IR data. The B-H loops of all samples obtained by using vibrating sample magnetometer (VSM) are displayed. The reduction of saturation magnetization of the nano-structured samples in comparison with their bulk counterparts and the effect of Zn addition on saturation magnetization of all the samples are discussed.