Barium Ferrite Research Articles

Bi-doped barium ferrite decorated polythiophene nanocomposite: influence of Bi-doping on structure, morphology, thermal and EMI shielding behavior for X-band

The electronic and communication devices such as mobile, laptop, and radio ease our day-to-day life. However, these devices emit harmful radiation, which affects human health and the environment. Therefore, to prevent such radiation-based pollution and provide a safer working environment, viable and promising EMI shielding materials have been investigated. Keeping this in mind, the present work reports the relatively low-temperature synthesis of bismuth-doped barium ferrite (BaBixFe12−xO19, Bi-BFO) nanoparticles and their nanocomposite via sol–gel and in situ emulsion polymerization approaches for their application in EMI shielding material. The influence of Bi-doping on phase purity, morphology, structure, and thermal behavior has been explored. The EMI shielding properties of these materials have been investigated in the X-band (8.2–12.4 GHz) region. The composite (Bi-BFO:PT = 2:1 Bi-BFO/PTh-21) with 1 mm thickness exhibited maximum shielding effectiveness (SE) of − 47.12 dB in the X-band region. The high shielding activity is mainly due to the efficient complementarities between the magnetic and dielectric loss. The doping of Bi in barium ferrite results in the increase in electrical polarization that led to the high dielectric loss, causing higher absorption of electromagnetic (EM) waves. These studies suggest that the nanocomposite may find its scope as an excellent microwave absorber for a wide frequency region.

Requisite of Surfactant (CTAB, n-Heptane, and Tri-sodium Citrate) Levels on Enhancement of Magnetic Property and Morphology Changes of Barium Ferrite (BaFe2O4) Nanoparticles

The barium ferrite (BaFe2O4) nanoparticles were synthesized through auto-combustion method using surfactants (CTAB, n-heptane, tri-sodium citrate) with three different mole ratios such as 0.04 M, 0.06 M, and 0.08 M. The variation of mole concentration of surfactants affects the particle size, morphology, and magnetic properties of barium ferrite nanoparticles. This work has optimized the mole concentration of respective surfactants and identifies the best performance of surfactant in barium ferrite nanoparticles. After calcination, the formation of barium ferrite (BaFe2O4) was observed by XRD. The prominent orientation of (212) was to perceive for all concentration of surfactants. Specific vibration on 770 cm−1 indicated the formation of barium ferrite (BaFe2O4) in FTIR analysis. In metallic vibration occurred small shift from 469.23 to 464.10 cm−1 due to change in particle size. Spherical-, platelet-, and rod-shaped particles were founded which was clearly visualized from FESEM and TEM images. The impact of best performance of surfactant in morphological change was identified as n-heptane. The VSM results revealed the highest saturation magnetization (Ms) as 32.52 emu/g with 4228 Oe coercivity (Hc). These results showed the ferromagnetic behaviour and different surfactants were supported for this strong behaviour of barium ferrite nanoparticles. Dielectric constant also changed from 45.11 to 88.52 for different surfactants in barium ferrite nanoparticles, which was observed by dielectric analysis.

The magnetic property alterations due to transition from barium ferrite (BaFe2O4) nano rods to barium carbonate (BaCO3) quantum dots

Barium carbonate (BaCO3) quantum dots and barium ferrite (BaFe2O4) nano rods were synthesized by combustion method. The structural, morphological and magnetic properties were characterized by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), field emission scanning microscopy (FESEM), Transmission Electron Microscopy (TEM), Energy-dispersive X-ray spectroscopy analysis (EDAX) and vibrating sample magnetometer (VSM). The crystallinity with orthorhombic structure of BaCO3 and BaFe2O4 nanoparticles were confirmed by XRD pattern. The FTIR spectra also indicate the formation of both BaCO3 and BaFe2O4 from specific metallic vibration. The morphological analysis confirms the formation of BaCO3 quantum dot and barium ferrite nano rods which is clearly visualized from the FESEM and TEM images. The annealing process caused this vivid transition in morphologies. The BaCO3 quantum dot produced an important change in magnetic property over BaFe2O4 nanorods which are evidenced from saturation magnetization (Ms) and coercivity (Hc).

Synthesis of broad microwave absorption bandwidth Zr4+-Ni2+ ions gradient-substituted barium ferrite

In this study, to effectively broaden the absorption bandwidth of M-type barium ferrite (BaM) in frequency range 2–18 GHz, Zr4+-Ni2+ ions gradient-substituted BaM samples were synthesized via secondary heating the mixtures of homogeneous-substituted Ba(ZrNi)0.6Fe10.8O19 and Ba(ZrNi)0.7Fe10.6O19. Effects of primary and secondary heat treatment on electromagnetic (EM) parameters of gradient-substituted BaM were investigated in detail. Permittivity values of samples are mainly controlled by primary heat treatment, enhancing with increasing temperature, whereas magnetic loss range is enlarged by improving primary and secondary heat treatment. As a result, the frequency range with μ" value > 0.3 reaches to 6.84 GHz for the sample “1400–1200 °C”. Enhanced dielectric and magnetic losses contribute high attenuation constant over wide frequency range, finally resulting in broad absorption bandwidth of 6.24 GHz at matching thickness of 2.8 mm. The bandwidth improved by 21% and 44% compared to that of original Ba(ZrNi)0.6Fe10.8O19 and Ba(ZrNi)0.7Fe10.6O19, respectively. This study sheds new light on the preparation of broadband absorbing materials.

A preliminary study of oxides of Fe doped with Ba, Co, Cu and synthetized by the citrate sol–gel combustion route

In the present work we report the synthesis of mixed ferrites doped with Co2+, Cu2+ and Ba2+ cations, using citrate sol–gel combustion route in air atmosphere, at 950 °C for 3 hours, produced substituted M-type barium ferrites powders particles with crystallite sizes varying between 145 and 155 nm. The percentages of yield obtained were on average 42%. The synthesized ferrites were characterized by techniques such as powder X-ray diffraction, evidencing the formation of M-type barium hexaferrite and copper and cobalt substituted M-type barium ferrite with hematite in smaller proportion. The possible growth of M-type barium ferrite with copper and cobalt may be due to a larger size of the cobalt atom with respect to copper and that a higher proportion of cobalt salt was used in the synthesis route. Increase in the metal ion substituted content leads to a decrease in the lattice strain and may be responsible for an increase in the crystallite size because greater tensile strain leads to elongation of the particles. The particle size of the synthesized ferrites differs significantly when they are doped, with Ferrite doped with copper having the smallest particle size compared to Ferrite doped with cobalt. We also performed spectroscopic analyses, RAMAN that showed, the substitution of cooper or cobalt in the M-type barium ferrite powders particle leads to a minor intensity of resonance band when compared with the parent compound and the differences between Fe3+, Cu2+ and Co2+ ions in a tetrahedral coordination is their ionic radii. The increase in the ionic radii causes a local distortion and vibrational bands of distorted polyhedra in substituted M-type barium ferrites. The chemical composition of this sample was determined as Ba1.0Fe11.83O19.22, Ba1.0Co1.02Fe11.01O18.35 and Ba1.02Cu0.56Fe11.35O18.26 using an AAS device. Both are very close to the theoretical formula. The influence of the synthesized ferrite samples was explored in the ozonation of a dye of unknown chemical structure. The effect was evidenced by visible ultraviolet spectroscopy technique. The results obtained show that the ink could be decolorized by applying oxidation by ozonation, however, when substituted M-type barium ferrite is added, the discoloration increases when this is doped with copper and cobalt, being higher using this last ferrite. The degradation process by ozonation presented in this work, carried out in the presence of copper and cobalt substituted M-type barium ferrites, would constitute an example of technology for the environment.

Influence of La, Mn and Zn Substitution on the Structure, Magnetic and Absorption Properties of M-Type Barium Ferrites

A series of M-type barium ferrites with chemicals composition BaFe12O19 and Ba0.7La0.3Fe(12-2x)(MnZn)xO19 (with x = 0.0, 0.2, 0.5) were synthesized using a chemical coprecipitation based technique. The sample was then called as BFO and BLF, BLFMZ-02 and BLFMZ-05, respectively. The structural parameters were measured by applying the full pattern fitting of Rietveld method using Fullprof program. The crystallite size was calculated using Scherrer formula and Williamson-Hall analysis method, and also confirmed by scanning electron microscope (SEM) and transmission electron microscope (TEM). The morphology of particle is composed of fine-grained aggregates with particle size distributions in the range of 70nm - 160nm. The lattice parameter (a = b and c), cell volume (Vcell) and density (ρ) of the samples were found to be changed with La, Mn and Zn substitution due to the dissimilar cationic radii of Ba2+ (1.49Å), La3+ (1.22Å), Fe3+ (0.64Å), Mn3+ (0.89Å) and Zn2+ (0.76Å) ions. The results of sample measurements with Vibrating Sample Magetometer (VSM) indicate that the magnetic behaviours showed that the saturation magnetization (Ms) increased gradually with the substitution of La3+, Mn3+ and Zn3+ ions, whereas the coercivity (Hc) was increase with addition of La3+ ions and then decrease significantly with the addition of Mn3+ and Zn2+ ions. The vector network analyzer (VNA) revealed that microwave absorption measured within 7 – 15 GHz frequency range indicated optimum reflection loss (RL) of-21.50dB at 10.5GHz for BLMZ-02 sample.

Correlation between the Chemical Composition, Crystal Structure, and Magnetic Properties of Hexagonal Barium Ferrite with Zn2+ Heterovalent Substitution

This paper presents a detailed study of the magnetic and crystal structures of BaFe12 –xZnxO19 (0.25 ≤ x ≤ 1.5) Zn-substituted barium hexaferrite by Mossbauer spectroscopy, vibrating sample magnetometry, and X-ray diffraction. Partial heterovalent substitution of Zn2+ ions for Fe3+ ions demonstrates limited heterovalent isomorphism according to the scheme 2Fe3+ → Zn2+ + Fe4+, which satisfies the electroneutrality constraint. Mossbauer spectroscopy results indicate the presence of Fe4+ in the BaFe12 –xZnxO19 materials. The heterovalent isomorphous substitution limit has been determined to be x = 1.0. The formation of a zinc spinel has been shown to begin at x = 0.50 and its content increases with increasing zinc content. Data are presented on the predominant character of the substituent ion (Zn2+) distribution in the structure of barium hexaferrite. A correlation has been found between the chemical composition, phase separation, anisotropy of properties, and the temperature of the magnetic phase transition of BaFe12 –xZnxO19 (0.25 ≤ x ≤ 1.5).

BARIUM AND STRONTIUM FERRITS SYNTHESIZED IN THE SUN FURNACE

Magnetic materials synthesized from a melt in a solar furnace were studied. It is shown that melts consist of crystallites of a metastable structure and an amorphous phase. This state contributes to a directed change in structurally sensitive properties (electrical, magnetic, and optical). It has been revealed that the magnetization values of barium and strontium ferrites synthesized from a melt in a stream of concentrated solar radiation increase 1.8 times in comparison with materials synthesized from solid-phase reactions. KEYWORDS- ferrites, magnetic material, solar furnace, structural defects, magnetization.

Effects of Mn–Zr substitution on the magnetic properties of Ba-ferrites fabricated by sol–gel auto-combustion

Polycrystalline samples of BaMnxZrxFe11.5−2×O18.25 having different doping contents of Mn–Zr were fabricated and their magnetic properties investigated accordingly. The results show that the average crystalline size of this specimen is about 150 nm. As the doping content, x, of Mn–Zr increases from 0.1 to 1, the coercive force, Hc, continuously decreases from 368 kA/m to 120 kA/m, while the saturation magnetization, Ms, initially increases, and then subsequently decreased. The maximum Ms obtained in BaMnxZrxFe11.5−2×O18.25 with x = 0.3 is 63.03 Am2/kg. Moreover, residual magnetization, Mr, increases initially and then consistently decreased as the doping content, x, increases. The maximum Mr obtained when x is 0.2 is 30.85 Am2/kg. This study suggests that the magnetic properties of Barium ferrites can be adjusted to suit various application requirements by doping with different Mn and Zr contents at Fe sites.

Crystal structure, morphology and magnetic properties of hexagonal M-type barium ferrite film based on the substrate temperature

In this paper, a hexagonal M-type barium ferrite (BaM) film with a high remanence ratio was deposited on a sapphire substrate by the pulsed laser deposition (PLD) method. The characterization results showed that the film growth at a high substrate temperature (950 °C) has a high out-of-plane orientation, good crystallinity, and smooth surface. Additionally, the hysteresis loops indicated that the film deposited at a high substrate temperature has a high remanence ratio of 0.53, which is higher than that of the other reported BaM films prepared by the PLD method.

Synthesis of barium ferrite, using barite mineral ore and a metallurgical waste

Samples of barite mineral ore, were ground to a mesh of 250, and then were subjected to a leaching stage with hydrochloric acid at different times, then; the leached barite mineral ore was subjected to a carbonation stage controlling different parameters such as pH, temperature, time and speed of agitation. Finally, it was subjected to a sintering stage with the Fe2O3 precursor obtained from the waste powder of the steelmaking company’s rolling process, in a temperature range of 1000 and 1200 ° C, for 12 and 24 times. The materials obtained are characterized by infrared spectroscopy (IR Spectroscopy), X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM).

3D Printing of ABS Barium Ferrite Composites.

In this work, a process for the realization of new polymer matrix composites with nanosized barium ferrite (BaFe12O19) as ferrimagnetic filler, acryl butadiene styrene (ABS) as polymer matrix and an extrusion-based method, namely fused filament fabrication (FFF), as 3D printing method will be described comprehensively. The whole process consists of the individual steps material compounding, rheological testing, filament extrusion, 3D-printing via FFF and finally a widespread specimen characterization regarding to appearance, mechanical properties like tensile and bending behavior as well as the aspired magnetic properties. Increasing ferrite amounts up to 40 vol.% (equal 76 wt.%) cause a reduction of the ultimate stress and an increase of the magnetic polarization as well as of the energy product (BH)max in comparison to the pure polymer matrix. In addition, an extensive discussion of typical printing defects and their consequences on the device properties will be undertaken.

Neodymium ions activated barium ferrite composites for microwave X-band absorber applications: Synthesis and characterizations

Abstract Some composites of barium ferrites activated with the neodymium ions (Nd3+) of composition (20)BaO:(80-x)γ-Fe2O3:(x)Nd2O3 (x = 0, 1 and 2 mol%) were synthesized using the modified mechanical alloying for the first time. The influence of varying Nd3+ concentrations on the morphologies, microstructures, and magnetic characteristics of these composites were evaluated. In addition, the microwave (MW) reflection loss, complex relative permittivity, and permeability of the studied composites in the frequency range of 8.2–12.4 GHz were analysed using the Nicholson-Ross-Weir (NRW) method. The inclusion of Nd3+ in the proposed composites was discerned to influence the permittivity, permeability and reflection loss significantly in the MW X-band region.

Magnetic and microwave absorption properties of Mn4+ doped barium-natural ferrites prepared by the modified solid-state reaction method

Microwave wide-spread results in electromagnetic interference, environmental pollution, and hazards for health, thus microwave absorber is immediately needed. Mn4+doped barium natural ferrites were synthesized using the modified solid-state reaction method, which is a combination of the sol-gel method and the solid-state reaction. Commercial Ba(NO3)2, MnO2 and natural Fe3O4 were used as raw materials. Structural, magnetic properties and microwave absorption of the barium ferrites were characterized using XRD, VSM, and VNA, respectively. The results reveal that phase of BaFe2.37Mn9.63O19 dominates the diffraction peaks with the average size of crystallite 23.74 nm after adding Mn4+ ions in the barium ferrites. Ms value of the barium ferrite decreases with increasing concentrations of Mn4+ due to the surface effect of the nanoparticle. The MBF3 exhibited excellent performance that absorbs all given microwave frequencies with RL below -10 dB and bandwidth of 4 GHz compared to the other samples.

Synthesis of Carbon Nanotubes on Cerium-Substituted Barium Ferrite Substrate by Chemical Vapor Deposition for Preparation of a Microwave Absorbing Nanocomposite

In this research, at first, Ce-substituted barium ferrite, BaCe0.2Fe11.8O19 was prepared via the sol-gel method as a substrate and then Carbon NanoTubes (CNTs) was synthesized on the surface of the substrate by Chemical Vapor Deposition (CVD) technique. The structure, morphology, and electromagnetic performance of the synthesized nanocomposites were characterized by XRD, FE-SEM, and Vibrating Sample Magnetometer (VSM), respectively. The results indicated that the BaCe0.2Fe11.8O19 particles were coated by CNTs, and the nanocomposite has magnetic properties. Therefore, the electromagnetic properties including complex permittivity (er), the permeability (µr), and microwave absorption properties were investigated using a vector network analyzer. It was found that in the nanocomposite, because of the presence of CNTs, the Reflection Loss (RL) widely increased. The maximum reflection loss in the frequency range of 8-12 GHz for 2.5 mm thickness was -49.61 dB at 9.0 GHz. The results suggest that prepared nanocomposite can be suitable in the microwave absorbing coatings.

Electromagnetic Properties of Hexaferrite Polymer Composite Materials

In this paper the results of studies of the electromagnetic characteristics of composite radio materials based on Z-, W-, M-type barium ferrites and epoxy resin are presented. The frequency dependences of the reflection, transmission, and absorption coefficients are shown. The obtained results of the electromagnetic response are in good agreement with the published data on the frequencies of natural ferromagnetic resonance for the types of ferrites considered. Based on the obtained data, the spectra of complex dielectric and magnetic permeabilities were calculated. It has been suggested that the above changes in the complex magnetic permeability are associated with the presence of domain wall resonance in the region of 1 GHz and natural ferromagnetic resonance at higher frequencies.

Enhancement of Saturation Magnetization and Remanence of BaFe12O19 Materials Prepared by NaCl–KCl and Hexamine as Flux

Hexagonal platelet barium ferrite was produced through a two-step molten salt synthesis calcined at 850 °C for 5 h with NaCl–KCl as flux, followed by calcination at 400 °C for 5 h with hexamine. Influence of NaCl–KCl and hexamine on the structural, phase composition, surface morphology, and magnetic properties of BaFe12O19 was studied by X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric/differential analysis, scanning electron microscopy, and a superconducting quantum interference device. The particles exhibited M -type barium hexaferrite nanoparticles with a product yield of 97.8% with a mean crystallite size of 81 nm for NaCl–KCl and 50 nm for hexamine. The infrared spectrum showed tetrahedral and octahedral positions in the absorption bands of hexagonal ferrite. As the atomic ratio of Ba:Fe:O is found to be 1:12.3:17.6, which is close to the stoichiometric ratio of BaFe12O19, it confirms the hexagonal structure of the sample. The plates are found to agglomerate, and variation in particle size was observed using scanning electron microscopy. The samples revealed better magnetic properties with a high saturation magnetization of 165.3 emu/g, higher remanence of 58 emu/g, coercivity of 929 Oe, and a squareness ratio of 0.35. This investigation was performed to examine the microstructure and the effect of crystallinity of the submicrometer BaFe12O19 powders on magnetic properties. This study also provides a promising method and total processing parameters to synthesize hard ferrite powders with improved hard magnetic properties and fine crystallite size.

Barium Ferrite Magnetic Nanoparticles Labeled with 223Ra: A New Potential Radiobioconjugate for Targeted Alpha Therapy and Magnetic Hyperthermia

Among all alpha particle emitters, only a few nuclides are of considerable interest for targeted radionuclide therapy because of their properties, such as half-live, high cytotoxicity and short path length. One of the most important issues, which affects wider use of targeted α therapy in nuclear medicine, is the availability and the price of the radionuclides. 223Ra, as radium chloride, is the first commercially and widely used α-radiopharmaceutic. It is easily obtained from the 227Ac/223Ra generator. However, 223Ra is used mostly for treatment of bone metastases derived from primary prostate cancer, because 223Ra, as a member of alkaline earth metals, forms very weak complexes. There is a lack of chelators which can effectively bind 223Ra for the purposes of receptor targeted therapy. In our studies we propose to use barium ferrite (BaFe12O19) nanoparticles as multifunctional carriers for 223Ra radionuclide for targeted α therapy and magnetic hyperthermia. Barium hexaferrite nanoparticles labeled with 223Ra were synthesized by a modified autoclave method described by Drofenik et al [1]. The reaction mixture of FeCl3, BaCl2 and 223RaCl2 was alkalized with NaOH solution. Next, the reaction mixture was stirred in autoclave at 210 Celsius degrees for 5 h. Obtained radioactive, magnetic [223Ra]BaFe12O19 nanoparticles were washed with distilled water and hydrochloric acid (0.001 mol/L HCl). Yield of labeling was about 70% (for 100kBq 223Ra). Stability of the obtained radioactive nanoparticles was tested in various biological solutions: 0.01M PBS,0.9% NaCl and in human blood serum. It is confirmed that 223Ra was highly retained inside nanoparticles in every tested solution. Only about 20% of 211Pb (decay product of 223Ra) was released to the solution. Obtained magnetic BaFe12O19 nanoparticles were characterized by transmission emission microscopy and dynamic light scattering. The diameter of synthesized nanoparticles was ∼20 nm and the determined magnetization of nanoparticles in room temperature was about 42 emu/g. In order to synthesize a radiobioconjugate having affinity to HER2 receptors, the monoclonal antibody trastuzumab was conjugated to the obtained barium ferrite nanoparticles. Firstly, the surface of barium ferrite nanoparticles was modified with 3-phosphonopropionic acid (CEPA) linker using a method described by Mohapatra et al [2], and then, the monoclonal antibodies were coupled to the barium ferrite nanoparticles using the carbodiimide chemistry. Synthesized bioconjugate was characterized by thermogravimetric analysis, dynamic light scattering and were tested for stability in biological fluids. The obtained [223Ra]BaFe12O19CEPA-trastuzumab radiobioconjugate almost quantitatively retains 223Ra and majority of the daughter products. Radiobioconjugate has high receptor affinity towards HER2 receptors expressing on ovarian cancer cells and exhibits high cytotoxic effect in vitro. This work was supported by National Science Centre of Poland (Grant NCN Preludium 2015/17/N/ST4/03943). [1]M.Drofenik et al Mat.Chem.Phys. 2011; 127: 415–419.[2]S.Mohapatra et al Nanotechnology 2007; 18: 385102–11.

Microwave absorbing characteristics in multilayer absorbers based on barium ferrite and teflon

In order to investigate a new microwave absorbing characteristics of multilayer absorbers. Barium ferrite BaFe12O19 was synthesized by a standard ceramic method. Teflon was obtained from the china product and is available in the market. Multilayer absorbers based on 2 mm of barium ferrite layer thickness and 0.5 mm of teflon layer thickness with 2, 4, 6 and 10 layers were characterized by using vector network analyzer (VNA) Rohde-Schwarz ZVA 67 for 7.5 – 11.5 GHz frequencies. Reflection loss (RL) of multilayer absorbers were calculated and simulated using the transmit line theory. The microwave absorption abilities were enhanced for multilayer structure due to the combination of barium ferrite and teflon layers. The optimal absorption ability was achieved with − 20 dB (i.e. 99.9 % absorption) of reflection loss.

Peculiarities of the Crystal Structure and Texture of Isotropic and Anisotropic Polycrystalline Hexagonal Ferrites BaFe12O19 Synthesized by Radiation-Thermal Sintering

In this work the crystal structure and texture of isotropic and anisotropic polycrystalline hexagonal ferrites BaFe12O19 obtained by the method of radiation-thermal sintering (RTS) is studied using X-ray diffraction and X-ray phase analysis. Crude blanks of both isotropic and anisotropic hexaferrites are obtained by the standard method of ceramic technology from the same raw material (Fe2O3 and BaCO3 of the analytical grade brand) and on the same equipment with the only difference being that the anisotropic blanks were pressed in the magnetic field H = 10 kOe. For sintering raw billets, a linear electron accelerator ILU-6 (electron energy Ee = 2.5 MeV) is used (Budker Institute of Nuclear Physics, Siberian Branch, Russian Academy of Sciences). The samples are sintered in air for one hour at 1200, 1250, 1300, and 1350°C. It is shown for the first time that high-quality single-phase isotropic and anisotropic hexaferrites BaFe12O19 can be obtained from raw blanks of a ferritized charge using the RTS technology. The properties of the crystal structure and texture of the obtained objects of the research are described. It is established for the first time that the dependence of the pref.orient.o1 predominant orientation of the crystal texture parameter on the degree of the magnetic texture f in polycrystalline hexagonal barium ferrites of type M is described by the expression pref.orient.o1 = –0.005f + 0.6886.