Increase In Magnetic Saturation Research Articles

Fabrication of rare earth dysprosium doped Ca-Cu (1:1) based Ca0.5Cu0.5Fe12–xDyxO19 ferrites for structural and magnetic investigations

Hexaferrites' magnetic and structural properties are highly sensitive to changes in sintering temperature and cationic replacements. We fabricated Ca0.5Cu0.5Fe12–xDyxO19 hexaferrites using the sol-gel technique. We examined the phase, microstructure and magnetic aspects of the samples with respect to varying doping of rare earth dysprosium. The results show the expansion in the lattice upon incorporation of dysprosium against iron. Morphological studies confirm the uniform distribution of particles with slightly longitudinal nanoflakes in one direction. Magnetic investigations show an increase in magnetic saturation (Ms) with increasing dysprosium incorporation till optimum level is achieved for 15% doping concentration, with negligible change for maximum doping level. Furthermore, coercivity (Hc) and magnetic moment (mB) in terms of Bohr’s magneton (μB) also show an increasing trend with dysprosium substitution levels. The maximum saturation magnetization of 33.355 emu/g is achieved with magnetic remanence of 18.290 emu/g, along with optimum magnetic moment of 6.249 μB. In addition to the traditional magnetic parameters, magnetic anisotropy parameters were explored for the deep insights into magnetic parameters. These outcomes suggest that improved magnetic properties of Ca0.5Cu0.5Fe12–xDyxO19 ferrites make it good substitute for storage devices, magnetic filters, and other magnetic applications.

Structural, Optical, Electrical, and Magnetic Characterization of PC/PEO Blend Incorporated with ZnFe2O4 Nanoparticles

In this study, zinc ferrite nanoparticles (ZnFe2O4 NPs) were incorporated into a polycarbonate/polyethylene oxide (PC/PEO) blend using the casting method. The resulting blends were subjected to comprehensive analysis using various techniques. X‐ray diffraction (XRD) analysis revealed that the presence of ZnFe2O4 nanoparticles had a significant impact on the crystal structure of the PC/PEO blend, leading to a reduction in crystallinity. Fourier‐transform infrared (FT‐IR) measurements further confirmed the uniform distribution and compatibility of PC and PEO as polymer components, as well as their compatibility with the blend containing ZnFe2O4 NPs. The optical properties of the PC/PEO blend, including band gap and Urbach energy, were quantified using the Kubelka–Munk method. The incorporation of ZnFe2O4 NPs resulted in the formation of sub‐band states between the valence and conduction bands, leading to a decrease in the band gap values. Field emission scanning electron microscopy (FESEM) analysis revealed a noticeable modification in the surface roughness, with the addition of ZnFe2O4 NPs resulting in a smoother surface texture. The electrical properties of the blends, including dielectric constant, dielectric loss, and AC conductivity, were measured. The addition of ZnFe2O4 NPs increased the dielectric constant (ε′) at lower frequencies, while it remained relatively stable at higher frequencies due to the localized charge carriers within the polymer blend. The higher values of ε’ observed at lower frequencies can be attributed to the movement of ions, which contributes to enhanced ionic conductivity. The magnetic properties of the blends were evaluated, demonstrating an increase in magnetic saturation upon the addition of ZnFe2O4 NPs. These findings provide valuable insights into the structural, optical, electrical, and magnetic characteristics of PC/PEO blends incorporated with ZnFe2O4 nanoparticles, thereby highlighting their potential for a wide range of technological applications.

Effect of Synthesizing Temperature on the Structure and Magnetic Properties of The Co-Ferrite

This study explores the preparation of Co-nano ferrites using the glycine-nitrate auto-combustion method at different synthesis temperatures. The crystal structure, magnetic properties, and morphological traits were investigated using X-rays in diffractometry, a vibrating sample magnetometer, and scanning electron microscopy. Based on the X-ray diffraction (XRD) data, it can be observed that the products produced possess a cubic spinel structure. As the temperature for synthesis is elevated from 100°C to 250°C, there is an observed increase in the size of the crystallites from 21nm to 25nm. Furthermore, an increase in the synthesizing temperature led to a reduction in the lattice constant, which decreased from 8.4155 Å to 8.3565 Å. Scanning electron microscopy (SEM) images, accompanied by histograms, revealed that the ferrite nanoparticles exhibited a tendency to aggregate, as indicated by a variance of around 100 and a standard deviation of 10. The VSM data indicate that an increase in synthesis temperature leads to a corresponding increase in magnetic saturation.

Influence of Dissolving Fe-Nb-B-Dy Alloys in Zirconium on Phase Structure, Microstructure and Magnetic Properties.

This paper refers to the structural and magnetic properties of [(Fe80Nb6B14)0.88Dy0.12]1−xZrx (x = 0; 0.01; 0.02; 0.05; 0.1; 0.2; 0.3; 0.5) alloys obtained by the vacuum mold suction casting method. The analysis of the phase contribution indicated a change in the compositions of the alloys. For x < 0.05, occurrence of the dominant Dy2Fe14B phase was observed, while a further increase in the Zr content led to the increasing contribution of the Fe–Zr compounds and, simultaneously, separation of crystalline Dy. The dilution of (Fe80Nb6B14)0.88Dy0.12 in Zr strongly influenced the magnetization processes of the examined alloys. Generally, with the increasing x parameter, we observed a decrease in coercivity; however, the unexpected increase in magnetic saturation and remanence for x = 0.2 and x = 0.3 was shown and discussed.

Effect of High-Energy Ball Milling on Molten Salt Synthesized Barium Hexaferrite Powder

M-type hexagonal ferrite powder was prepared by the molten salt flux method calcined at a relatively low temperature (850 °C) with a product yield of 99.87%. The synthesized sample was then milled for 3 h by high-energy ball milling in toluene suspension to obtain ultrafine nanoparticles. The structural, morphological, and magnetic properties of the particles were investigated to observe the effect of milling on the molten salt synthesized powder. The analyses reveal the presence of barium hexaferrite (BaFe12O19) as the main phase with less impurities. Average crystallite size, determined by X-ray diffraction (XRD), decreased from 81 ± 20 nm to 52 ± 5 nm after ball milling. The Fourier transform infrared (FTIR) spectra ensure the tetrahedral and octahedral positions in barium hexaferrite structure with an increase in the intensity of absorption bands after milling. The electron paramagnetic resonance (EPR) signal shows a broad line that demonstrates a decrease in the amplitude of the milled sample. Furthermore, remanence measured by vibrating sample magnetometer (VSM) increases from 8.5 to 25 emu/g. A 72% increase in coercivity and 84% increase in magnetic saturation is observed for the milled samples compared to that of pure BaFe12O19 (unmilled). The variations of the magnetic properties are thus attributed to the reduction in crystalline size and lattice parameters after milling.

Effect of magnetic ion substitution on the structure and temperature-dependent magnetic properties of strontium hexaferrite

ABSTRACT Rare earth substituted strontium hexaferrite powders were synthesised through a molten salt route at 900°C for 5 h. The influence of rare-earth magnetic ion substitution on microstructural features, morphology and temperature-dependent magnetic properties was investigated. The lattice parameter ratio of less than 3.98 proves that all the substituted samples primarily present the hexaferrite phase. Fourier transform infrared peaks also confirmed the presence of a metal-oxygen bond. A 66% increase in magnetic saturation, 38% increase in coercivity and a more than two-time increase in remanence for the samarium doped sample are seen as the highest magnetic measurements compared to pure SrFe12O19 at room temperature. There were also differences in the temperature-dependent magnetic properties of strontium ferrites. As temperature decreased from 300 K, saturation magnetisation and remanence value were found to increase. This will perhaps be a promising material for magnetic field sensor application.

Magnetic fluid seal critical pressure calculation based on numerical simulations

Magnetic fluid seals are among the most common ferrofluid applications. One interesting area is the use of numerical simulations to determine the critical pressure, which is a basic parameter determining the possible range of seal operating pressures. The purpose of this study is to present the method of critical pressure calculations in magnetic fluid seals based on magnetic field numerical simulations, which will provide better results than the methods used previously. It is a relatively simple method and can help to reduce the difference between simulations and experiments. Different seal stage shapes, such as symmetric trapezoidal, asymmetric trapezoidal, and rectangular, were taken into account. The research shows that an increase in the magnetic fluid volume applied at the seal stage and a magnetic saturation increase in the seal gap allow the manufacturing inaccuracy influence to be reduced, meaning that the difference between the simulation and experiment results is smaller. In addition, in this paper, the pressure transfer mechanism between liquid rings of the multistage seal is analyzed to show its influence on the critical pressure value calculated based on simulations.

Effect of Tb/Y substitution on structural and magnetic properties of Fe-Nb-B-Tb type of high-coercive alloys

In the present work, we are focused on the influence of Tb/Y substitution on structural and magnetic properties of (Fe80Nb6B14)0.88Tb0.12-xYx (x = 0.02, 0.04, 0.06, 0.08, 0.1 and 0.12) nanocrystalline bulk alloys. The samples were prepared in the form of rods using the vacuum suction technique. The base alloy (x = 0) is characterized by an ultra-high coercivity and the Tb/Y substitution leads to an increase in magnetic saturation from 38 emu/g to 112 emu/g and the decrease in coercivity from 5.88 T to 0.05 T. However, optima of magnetic remanence and |BH|max parameter were observed. It was shown that the changes in magnetic properties are related to a partial replacement of Tb by Y in the unit cell of the Tb/Y2Fe14B phase. In the paper, the optimization of hard magnetic properties as well as its relation to phase composition and microstructure are widely discussed.

Magneto-Electric Response and Functionality in Barium Ferrite/Barium Titanate/Epoxy Resin Nanocomposites

Hybrid nanocomposites with barium ferrite and barium titanate nanoparticles embedded within an epoxy resin matrix, were prepared and studied, varying the fillers content. The morphology of the fabricated specimens was examined by means of scanning electron microscopy and energy dispersive X-ray spectroscopy. Dielectric and magnetic properties of the nanocomposites were investigated via broadband dielectric spectroscopy and magnetization tests, respectively. Fine dispersions of nanofillers were detected via electron microscopy in all studied cases. Dielectric permittivity increases with diminishing frequency and increasing temperature and filler content. Recorded relaxation processes are attributed to interfacial polarization, between matrix and nanoparticles, glass to rubber transition of the polymer matrix (α-relaxation), and re-arrangement of polar-side groups of the main polymer chain (β-relaxation). Magnetization and magnetic saturation increase with the amount of barium ferrite nanoparticles.

The testing of action of chemical extracts on soils by magnetic methods (abstract)

The participation of soil iron in the formation of physics-chemical features in feed of plants and microorganisms is well known. Because of the active role of Fe in soil landscapes the Fe state is taken into account in investigations of the genesis of soils. In spite of a relatively high content of iron in soils up to 40%–45% (relative to Fe) its numerical forms are diagnosed in a complex way by Ronthgen diffractometry, differential thermal analysis, and microscopy. Thus, chemical extracts are widely used in soil science. Extracted Fe is considered to be of amorphous, strong or weak crystallized forms. These gradations are of wide use but they are not correct. This is established by some authors by means of magnetic measurements and Mössbauer spectroscopy [Jeanory et al., Sci. Solids 135 (1986)] before and after magnetic separation and chemical extracts [Fine and Singer, Soil Sci. Soc. Am. J. 53, 191 (1989)]. We used the measurements of magnetic susceptibility and saturation and nuclear gamma resonance for the usual soils and electron paramagnetic resonance for weak magnetic Fe containing minerals (before the extract). Our results are comparable with the above research and lead to the next conclusions: (1) ordered alternations of magnetic parameters and results of action of extracts are absent; (2) the Mehra–Jackson extract (sometimes the Tamm’s extract) often extracts the crystallized magneticordered and paramagnetic silicate and superparamagnetic forms of Fe; (3) magnetic susceptibility and magnetic saturation increase in some types of soils (brown earth, ferralsol, alluvial soil) at dissolution of the alumosilicate part of soils because of enrichment by chemically strong particles of magnetite; (4) the conclusions on extracts (as far as crystallized silicate amorphous forms) do not have generalized characteristics.