Search

Magnesium ferrites doped with lanthanum (MgLaF) and cerium (MgCeF) were synthesized according to the combustion method. These ferrite-based nanoparticles showed improved adsorption properties for uranium ions. The maximum capacity of 138.95 and 152.39 mg/g were achieved at pH 5 after 30 min of contact with the MgLaF and MgCeF nanoparticles. The outcomes demonstrated that the nanoparticles have a high adsorption affinity for uranium ions (θ ≥ 0.9396). This adsorption affinity was not significantly affected by the presence of other ions, where the amount of uranium adsorbed from granite leach liquor on MgLaF and MgCeF reached 122.7 and 134.8 mg/g. [ABSTRACT FROM AUTHOR]

Incorporating suitable wave-absorbing agents into cement and performing appropriate electromagnetic modification is an effective way to realize electromagnetic wave-absorbing. In this paper, cement-based composites were prepared with slag, graphite and ferrite as wave-absorbing agents, and mechanical property test, microstructure test and reflectance test were carried out to investigate the effects of different dopants and sample thickness on the wave-absorbing properties and mechanical properties of cement-based composites. The results show that the cement-based composites have the best wave-absorbing performance when the doping of slag is 30% (mass fraction) and graphite is 5% (mass fraction), and there exists the best matching layer thickness. The reflection loss is -40.84 dB at 2.65 GHz when the thickness is 36 mm. When the cement-based composite is composed of 30% slag, 10% (mass fraction) ferrite, and the matching layer thickness is 36 mm, the cement-based composites have the lowest reflectivity of -26.63 dB at 2.53 GHz. Both slag and ferrite reduce the strength of cement-based composites, and graphite (no more than 5%) is able to fill in mortar pores at the early stage of cement hydration, which enhances early mechanical properties. [ABSTRACT FROM AUTHOR]

Ferrite samples with enhanced magneto-dielectric properties are more essential in electromagnetic applications. Therefore, a parent composition of Fe 3 O 4 has been modified by substituting 3 d transition metal elements (Co, Ni, Mn) at a single Fe atom using the co-precipitation synthesis method. The structural properties of the synthesized Fe 3 O 4 , NiFe 2 O 4 , CoFe 2 O 4 , and MnFe 2 O 4 samples have been evaluated from the X-ray diffraction patterns. The surface morphology and microstructures of the studied samples were studied by field emission scanning electron microscopy and the average grain size of all the studied samples varied from 60.11 to 106.03 nm. The magneto-dielectric properties were analyzed by frequency dependent permeability (μ) and permittivity (ε) measurements for the range of 100 Hz to 100 MHz. The conduction process for the synthesized ferrites has been noticed from the ac conductivity (σ ac). The localized relaxation mechanism for the studied ferrites has been observed from the variation of imaginary portion of the electric modulus (M") and the impedance (Z"). Moreover, the mismatch (Z/η ο) between the impedance of the antenna substrates (Z) made of the studied samples and air (η ο) has been evaluated from the permeability and permittivity. Finally, NiFe 2 O 4 has been derived as a suitable ferrite for miniaturizing devices over a frequency range of 10 kHz-6.5 MHz. [ABSTRACT FROM AUTHOR]

We studied magnetic phase transitions near the Curie temperature in the ferrite material with the composition using thermomagnetometric analysis and methods for recording the temperature dependences of initial magnetic permeability and specific electrical resistivity . The study provides a description of the equipment used and the key features of the experimental methods under consideration. During thermomagnetometric analysis in the cooling phase, it has been found that the temperature at which the material completes its transition to the ferrimagnetic state corresponds to the inflection point on the curve and the break point on the dependence graph. The established interaction between the parameters of transition processes may be useful for more accurate determination of the Curie temperature in ferrites. [ABSTRACT FROM AUTHOR]

In this study, a novel NiCuZn (Ni 0.24 Cu 0.21 Zn 0.55 Bi x Fe 2- x O 4 (x = 0,0.025, 0.050, 0.075)) ferrite composition (Ni/Zn molar ratio is 24/55) was successfully prepared by the addition of Bi3+ ion for substitution. It is demonstrated that Bi 2 O 3 served as an effective doping agent to reduce the sintering temperature to 900 °C and enhanced the high-frequency magneto-dielectric properties. Notably, the maximum permeability is ∼118 (@ 13.56 MHz) when x = 0.050 with a cut-off frequency of 47 MHz, which is nearly four times higher than that of the unsubstituted sample. In addition, an NFC antenna employing optimized ferrite as an electromagnetic shield sheet was designed and simulated. The results indicated that the chaotic and weakened magnetic field was recovered, and the biased resonant frequency was restored from 31.87 MHz to 13.68 MHz. These findings hold significant scientific importance and practical value in achieving superior electromagnetic shielding performance and miniaturization in NFC system. [Display omitted] [ABSTRACT FROM AUTHOR]

This report is on magneto-electric (ME) interactions in bulk composites with coaxial fibers of nickel–zinc ferrite and PZT. The core–shell fibers of PZT and Ni1−xZnxFe2O4 (NZFO) with x = 0–0.5 were made by electrospinning. Both kinds of fibers, either with ferrite or PZT core and with diameters in the range of 1–3 μm were made. Electron and scanning probe microscopy images indicated well-formed fibers with uniform core and shell structures and defect-free interface. X-ray diffraction data for the fibers annealed at 700–900 °C did not show any impurity phases. Magnetization, magnetostriction, ferromagnetic resonance, and polarization P versus electric field E measurements confirmed the ferroic nature of the fibers. For ME measurements, the fibers were pressed into disks and rectangular platelets and then annealed at 900–1000 °C for densification. The strengths of strain-mediated ME coupling were measured by the H-induced changes in remnant polarization Pr and by low-frequency ME voltage coefficient (MEVC). The fractional change in Pr under H increased in magnitude, from +3% for disks of NFO–PZT to −82% for NZFO (x = 0.3)-PZT, and a further increase in x resulted in a decrease to a value of −3% for x = 0.5. The low-frequency MEVC measured in disks of the core–shell fibers ranged from 6 mV/cm Oe to 37 mV/cm Oe. The fractional changes in Pr and the MEVC values were an order of magnitude higher than for bulk samples containing mixed fibers with a random distribution of NZFO and PZT. The bulk composites with coaxial fibers have the potential for use as magnetic field sensors and in energy-harvesting applications. [ABSTRACT FROM AUTHOR]

Novel hydroelectric cells exploit porosity and structural defects to dissociate deionized water for hydroelectricity generation. In the present study, these essential attributes have been engineered using Zr4+ doping in MgFe 2 O 4 using the facile sol-gel method. Comprehensive structural analysis performed using modern analytical techniques such as X-ray Diffraction (XRD) and Raman Spectroscopy ascertained the pure spinel cubic phase of the synthesized nanoparticles. Morphologically, the material was probed using Field-Emission Scanning Electron Microscopy (FESEM) analysis, identifying highly porous and agglomerated spherical grains. The mesoporous structure of the samples was further determined using Brunauer-Emmett-Teller (BET) surface examination. An inclusive evaluation employing Photoluminescence (PL) examination in the UV spectral region revealed the existence of oxygen-deficient sites and intrinsic defects inside the doped magnesium ferrites. These results were further validated using X-ray Photoelectron Spectroscopy (XPS). Significant lattice strain (≈2.5 × 10−3) and the presence of oxygen vacancies, defects, and mesoporosity influence water dissociation at the ferrite surface. These attributes were utilized to facilitate the generation of hydroelectric current. The maximum short circuit current values recorded for MgZr 0.05 Fe 1.95 O 4 (ZMF-1) and MgZr 0.10 Fe 1.90 O 4 (ZMF-2) were observed to be 6.3 and 11.6 mA, respectively, with corresponding output voltages of 0.77 V and 0.89 V. The incorporation of Zirconium (Zr) dopant not only enhances the hydroelectric current but also contributes to sustained current generation over extended periods. [Display omitted] [ABSTRACT FROM AUTHOR]

Walnut shell has been used in various experimental studies for different dyes removal, but it is exciting to study the adsorption behaviour of bio‐waste (walnut shell) in combination with spinel zinc ferrite which resulted in the formation of a novel material having magnetic properties and help in easy separation after the wastewater treatment. Novel magnetic walnut shell zinc ferrite (WSZF) composite has been synthesized and used to remove Malachite Green and Methylene Blue from aqueous solution in single and binary dye systems. Different techniques have been used to characterize the composite such as Fourier Transform Infrared Spectroscopy, X‐Ray Diffraction, Field Emission Scanning Electron Microscopy, Energy Dispersive Spectroscopy, Thermogravimetric Analysis and pHzpc. Adsorption of dyes were studied to see the effect of time, pH, adsorbent dose, dye concentration and temperature. The Lagergren pseudo second order model fitted well among various kinetic models employed. Langmuir adsorption isotherm best fitted with maximum adsorption capacities of 86.20 and 169.5 mg/g in single dye and 23.92 and 18 mg/g respectively in binary dye system for Malachite Green and Methylene Blue. Process was spontaneous and ΔH° were found positive, confirmed endothermic process of adsorption. The composite's regeneration capacity was studied for five cycles and at the end of five cycle the efficiency of the material was found to be around 80 % for both single as well as binary dye systems. It is concluded that the chosen WSZF will be the optimum solution for cationic dyes removal. [ABSTRACT FROM AUTHOR]

This research investigates the dielectric and magnetodielectric properties of spinel-type Cr3+-substituted cobalt ferrites with the general formula Co1−xCrxFe2O4 (x = 0.000, 0.125, 0.250, 0.375, 0.500) over a wide range of temperatures and frequencies. The samples are synthesized by solid-state reaction via ball milling for 12 h and sintering at 1200°C. The grain size estimated from scanning electron microscopic images shows a decreasing value with increased Cr3+ content. The compactness of grain size reduces the dielectric behavior as analyzed from the frequency-dependent complex permittivity. The temperature-dependent real permittivity reveals that the x = 0.125, 0.250, and 0.375 samples behave as relaxor ferroelectric compounds, whereas the x = 0 and 0.5 samples behave as diffuse ferroelectrics. Detailed analysis of the electric modulus from the complex permittivity reveals the grain boundary and grain contribution, respectively. Around the relaxation frequency, a notable magnetodielectric response (maximum 6.5%, in the presence of 1 T applied magnetic field at room temperature) is found for all samples. [ABSTRACT FROM AUTHOR]

Manganese zinc (MnZn) ferrite is one of the most used ferrite materials, while the investigations on sintering behaviors and magnetic properties of MnZn ferrite with ultrahigh metal oxide components are important supplements to the preparation knowledge of MnZn ferrite. In the formula triangle of the Fe 2 O 3 –ZnO–MnO 2 system, four representative formulas including 50%Fe–25%Zn–25%Mn, 80%Fe–10%Zn–10%Mn, 10%Fe–80%Zn–10%Mn, and 10%Fe–10%Zn–80%Mn were selective in this work to stand for medium-Fe, high-Fe, high-Zn, and high-Mn systems. The thermogravimetric aspects, phase compositions, microstructure features, magnetic properties, electromagnetic parameters, and electromagnetic wave absorbing properties of four samples were compared via the TG-DSC, XRD, XPS, SEM-EDS, VSM, and VNA analyses. It's suggested that the phase compositions and microstructures were dramatically affected by the iron content. After sintering, the high-Fe and medium-Fe systems present single Zn x Mn y Fe 2 O 4 (0 < x, y < 1) phase and condense structure, while some free superfluous oxides are concomitant in the high-Mn and high-Zn systems. The pore structure and number are positively correlated with the MnO 2 content in the Mn–Zn–Fe oxide system owing to the decomposition deoxygenation reaction. The magnetism study indicates that all four samples present good soft magnetic properties and less coercive force, while the high-Fe system displays the highest magnetic saturation intensity of 102 emu/g and the lowest magnetic coercivity. Due to the uniform composition, dense structure, and sufficient iron ingredient, the as-prepared MnZn ferrite with the formula of 80%Fe–10%Zn–10%Mn (high-Fe system) sintered at 1300 °C for 6 h demonstrates strong electromagnetism performance with the minimum RL peak of −42.03 dB at a veneer thickness of 8 mm. It's suggested that sintered MnZn ferrite with high-iron content demonstrates superior electromagnetic wave absorption properties. This work provided a batching formula foundation for the preparation of high-performance MnZn ferrites with high metal oxide constituents from pure oxide reagents or mineral materials. [ABSTRACT FROM AUTHOR]

Previous investigations commonly employed solid-state sintering to fabricate Ni-based ferrite ceramics to improve magnetic performance. A few researchers used the hot-pressing method to prepare Ni-based ferrites, but their porosity remained relatively high values (>2%), resulting in high ferromagnetic resonance line widths (Δ H). To date, the influence of high-temperature and high-pressure forming processes on Δ H and spin wave line width (Δ H k) in Ni-based ferrite ceramics has been rarely reported using hot pressing. This study utilized a uniaxial hot-pressing method and systematically investigated the effect of porosity, grain size and grain uniformity on the magnetic properties of Ni-based ferrite ceramics. Porosity played a crucial role in determining Δ H at different sintering temperatures. As the sintering temperature increased, the reduced porosity resulted in a decrease in Δ H. Under varying sintering pressures, the grain uniformity primarily affected Δ H. Increasing pressures led to more uniform grains, causing a decrease in Δ H. The Δ H k was directly associated with the grain sizes. With the increase of sintering temperatures, the grain sizes increased, leading to a decrease in Δ H k. Conversely, as the pressure increased, the decreased grain sizes brought the increased Δ H k. Compared to other hot-pressing results on the Ni-based ferrite ceramics, the optimized high-temperature and high-pressure processing with annealing significantly reduced the porosity of Ni-based ferrite ceramics (0.11%). In comparison with the solid-state sintering without pressures, the optimized hot-pressed Ni-based ferrite ceramics exhibited a 7% increase in saturation magnetization, a 63% reduction in Δ H and a 6.5% increase in Δ H k. The striking reduction of Δ H suggests that microwave devices assembled from Ni-based ferrite ceramics could withstand high power levels while minimizing lower electromagnetic losses, predicting promising applications for Ni-based ferrite materials in high-power microwave ferrite devices. [ABSTRACT FROM AUTHOR]

CoFe2O4, ZnFe2O4, NiFe2O4, Co0.5Ni0.5Fe2O4, Ni0.5Zn0.5Fe2O4, and Co0.5Zn0.5Fe2O4 are among the multicomponent ferrite nanoparticles that are created using the reverse microemulsion technique and a mixed surfactant. These nanoparticles are thoroughly characterized using techniques such as vibrating sample magnetometer (VSM), energy dispersive X‐ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FT‐IR), and X‐ray diffraction (XRD). All the nanoparticles display a cubic spinel crystal structure, according to the X‐ray investigation. As the concentration of zinc increases, there is a noticeable rise in the lattice constant because the size of Zn+2 is more than Co+2. This study also investigates the relationship between the magnetic characteristics of nanocrystals and their matching size, composition, and features. [ABSTRACT FROM AUTHOR]

The Mn-Zn ferrite with a composition of Mn0.25Mg0.08Cu0.25Zn0.42Fe2O4 has been synthesized in this study using the chemical sol-gel technique at a pH of 7. The sample was prepared and subsequently annealed at a temperature of 700°C. The nanocrystalline ferrite samples were subjected to characterization using X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), Thermogravimetry (TG), and Differential thermal analysis (DTA). The findings of these observations are delineated and deliberated. The sample's phase composition was verified using X-ray diffraction examination. The crystalline size was determined using Scherrer's formula and was observed to be within the range of 20-75 nm. Two notable stretching bands were seen in the FTIR spectra within the range of 400-650 cm-1. The spinel structure of the produced nanoparticles was confirmed by these two bands. The magnetic characteristics of the powder were examined using a Vibrating Sample Magnetometer (VSM). The presence of M-H hysteresis loops suggests that the produced nanoparticles have superparamagnetic properties, as evidenced by their low coercive force, remanent magnetization, and saturation magnetization values. [ABSTRACT FROM AUTHOR]

In this study, inverse spinel cubic ferrites MFe2O4 (M = Fe2+, and Co2+) have been fabricated for the high-capacity adsorptive removal of Hg(II) ions. The PXRD analysis confirmed ferrites with the presence of residual NaCl. The surface area of Fe3O4 (Fe-F) and CoFe2O4 (Co-F) material was 69.1 and 45.2 m2 g−1, respectively. The Co-F and Fe-F showed the maximum Hg(II) adsorption capacity of 459 and 436 mg g−1 at pH 6. The kinetic and isotherms models suggested a spontaneous adsorption process involving chemical forces over the ferrite adsorbents. The Hg(II) adsorption process, probed by X-ray photoelectron spectroscopy (XPS), confirmed the interaction of Hg(II) ions with the surface hydroxyl groups via a complexation mechanism instead of proton exchange at pH 6 with the involvement of chloride ions. Thus, this study demonstrates a viable and cost-effective solution for the efficient remediation of Hg ions from wastewater using non-functionalized ferrite adsorbents. This study also systematically investigates the kinetics and isotherm mechanism of Hg(II) adsorption onto ferrites and reports one of the highest Hg(II) adsorption capacities among other ferrite-based adsorbents. [ABSTRACT FROM AUTHOR]

The aim of this paper is to study and to model the dielectric behavior of two ternary composites prepared from a mixture of barium titanate (BaTiO3) and one of the two materials (iron oxide (Fe304) or ferrite) in epoxy resin matrix which the volume fraction is fixed at 70%. The time domain spectroscopy (TDS) method is used to characterize the samples under test in the range from direct current (DC) to 12.5 GHz. The conductivity behavior study is performed at a low frequency of 250 MHz, throughout this work. The study has therefore been focused on the effect of adding iron oxide and ferrite to titanate included in an epoxy matrix. In this work, we present a new approach to model the permittivity behavior of a ternary composite by the introduction of the shape factor for different mixture laws in order to best fit the model to experimental data. Subsequently, a comparison is made with these modified laws to determine the most suitable one. To predict the dielectric permittivities of the ternary composites and their shape factor coefficients in a quantitative manner, we use a numerical optimization method for identification the parameters of the theoretical model. These composite materials find their interest in the miniaturization of electronic components used in microelectronic circuits and in the telecommunication applications. [ABSTRACT FROM AUTHOR]

In order to prepare broadband and high-efficiency flexible fabrics, ferrite (Fe3O4)/graphene (rGO) absorbing particles were prepared by thermal decomposition method, and Fe3O4/rGO nanoparticles were loaded onto cotton fabrics by double immersion and double rolling to obtain flexible fabrics with excellent absorbing properties. Scanning electron microscopy and infrared spectroscopy were used to characterize the microstructure and composition of flexible fabrics, and the electromagnetic parameters of fabrics were tested and analyzed. The results show that when the load-to-mass ratio of Fe3O4/rGO is 15:1, the absorption effect of flexible fabric is the best. When the thickness of the composite absorber is 4 mm, the minimum reflection loss at 11.3 GHz reaches -18.4 dB, and the effective absorption bandwidth ranges from 10.63~11.72 GHz. This paper provides a reference for the design and development of high-efficiency and broadband flexible absorbers. [ABSTRACT FROM AUTHOR]

A series of Cu-substituted NiZn ferrite nanoparticles (Ni0.5Zn0.5-xCuxFe2O4; 0 ≤ x ≤ 0.2) were synthesized by the polyol method and then characterized and investigated for their efficiency for the adsorptive removal of Alizarin Red S (ARS) dye as well as for their reusability. The effect of Cu2+ substitution for Zn2+ on the phase formation, crystal structure, microstructure and magnetic properties was investigated. The powders were pure phases with a cubic spinel structure and a slight departure of the unit cell parameter from the expected linearity variation as a function of Cu2 content. The particles are ultrasmall sized nanoparticles (~4–6 nm) with an almost spherical shape. The surface chemistry and the core local structure of the nanoparticles were ascertained from infrared. Magnetic study revealed a superparamagnetic behavior, and the variation observed for the main magnetic characteristics was interpreted on the basis on the changes in chemical composition, cation distribution and nanoparticles morphology. Adsorption–desorption of ARS onto the nanoparticles was investigated by varying various physicochemical parameters. The ferrite member with x = 0.15 exhibited the best removal capacity. At the optimum pH (pH2.0) the adsorption was fast during the first stage of adsorption process. Three kinetic models were tested. The adsorption data were best fitted with the pseudo-second-order model. The adsorption isotherms were measured and analyzed by Langmuir and Freundlich models. Based on Freundlich model, the maximum adsorption capacity was found to be high (~ 181 mg g−1). Besides, good reusability performance was observed after five adsorption–desorption-regeneration cycles. The mechanisms of both adsorption and desorption were proposed. [ABSTRACT FROM AUTHOR]

The pseudo-potential PAW method of the density functional theory is employed to study the localization of superstoichiometric oxygen in ferrite CaBaFe4O7 with the orthorhombic swedenborgite structure. The geometric characteristics of oxygen defects are determined by the crystal lattice relaxation procedure. It is shown that the formation of defects in calcium and barium coordination are energetically unfavorable. Oxygen intercalation into structural trigonal iron-oxygen and Kagomé layers is more favorable. In these layers, two edge-sharing Fe2O5 bipyramides are formed instead of FeO4 tetrahedra connected via one oxygen atom. The structural instability of ferrite CaBaFe4O7 is shown to be caused by the population of anti-bonding 2p O states during oxygen intercalation. The asymmetric location of the intercalated oxygen ion relative to the neighboring iron ions promotes the appearance of local electric polarization, which can induce ferroelectric effects in the presence of ferromagnetic order. [ABSTRACT FROM AUTHOR]

Electric currents of medium and high frequencies are used for inductive heating and welding of steel products. Furthermore, magnetic concentrators are used for the optimisation of transfer so that they direct the currents at a specific area of the heat-treated steel product. After years of study and detailed experimental research, we have found out that the material behaviour during inductive heat treatment also depends on the type of concentrator applied. The character of the electric current passing through the steel products changes through the application of different concentrators which directly alter the structure and quality of the final product. Ferritic and magnetodielectric concentrators from different producers have been used in the research with HF inductive welding of steel pipes. [ABSTRACT FROM AUTHOR]

In response to the demands for high frequency, miniaturization, and high integration in electronic devices, such as inductors and DC-DC convertors, nickel–zinc ferrite thin films exhibit significant application value and development potential. For regulating the magnetic properties and microstructure of spin-sprayed polycrystalline ferrite materials, a comprehensive understanding of the impact of oxidant concentration on film reaction is essential. This study finds that as the concentration of the NaNO2 oxidant increases, the grain size of the nickel–zinc ferrite thin film samples progressively enlarges. Due to the preferential occupation of iron ions at the B sites, the saturation magnetization correspondingly increases. However, when the oxidant concentration becomes excessive, the preferential (222) orientation growth of the film is disrupted, leading to the agglomeration and uneven growth of grains, transitioning from triangular plate-like to spherical in shape. This increase in grain size alters the magnetization mechanism of the thin film, predominantly favoring domain wall movement. Upon analyzing the microstructure and magnetic characteristics, it becomes evident that the concentration of oxidant is a key determinant in the spin-spray deposition process. [ABSTRACT FROM AUTHOR]

In this study, we investigate the magnetization behavior of coaxial nanowires fabricated through the sol-gel electrospinning method. Our analysis uncovers a significant reduction in coercivity for CoFe 2 O 4 nanowires when BaTiO 3 is used as the shell material, effectively transforming them from hard to soft magnetic. This intriguing behavior is attributed to the magnetization reversal effect at the interface between ferromagnetic and paramagnetic regions, and it is also observed in NiFe 2 O 4 and Fe 2 O 3 nanowires. Surprisingly, introducing a GdBa 2 Cu 3 O 7 shell induces a similar effect. Additionally, we employ magnetic impedance measurements on the coaxial nanowires, unveiling their potential for magnetic field sensing applications. [ABSTRACT FROM AUTHOR]

The austenite-ferrite transformation is the key metallurgical tool to tailor properties of low alloyed steels and remains an active area of research. Models have yet to be developed with truly predictive capabilities for phase transformations in multi-component commercial steels. This review provides a critical analysis of the various austenite-to-ferrite diffusional transformation model approaches that have been significantly broadened over the past decade by modelling at different length scales, i.e. classical macro-scale models have been augmented with simulations at the meso-scale and atomistic scale. Both semi-empirical and fundamental models are reviewed with an emphasis on polygonal ferrite formation in low and medium carbon steels. Formation of ferrite with more complex morphologies (i.e. irregular/bainitic/Widmanstätten ferrite) is also discussed. In particular, approaches to describe the interaction of alloying elements with the austenite-ferrite interface are critically analysed. The paper concludes with an outlook on the proposed austenite-ferrite transformation modelling work for the next decade. [ABSTRACT FROM AUTHOR]

Nickel ferrites (NIFs) come under the class of soft ferrites or transformer ferrites, which are highly demanding in the electronics industry and possess usual low conductivity and ferromagnetic properties, which results in decreased eddy current losses, good electrochemical stability, catalytic action, and abundance in nature. We discuss the synthesis, characterization, and impact of synthesized NIF fillers on the mechanical and solvent transport characteristics of rubber composites. Doped ferrite composites made of natural rubber and nitrile rubber were cured at various temperatures, and the solvent swelling properties of composites containing differently doped NIFs were examined in aromatic solvents like toluene. Properties of both rubber composites were examined, including their morphology, solvent uptake, diffusion coefficient, transport mechanism, and thermal stability. Natural rubber composites found to have better swelling properties than that of nitrile rubber composites. The solvent uptake was reduced with increase in filler loading also, the increase in sorption temperature increases the swelling rate in both systems. Theoretical calculations and modelling clearly state that the diffusion mechanism is due to the polymer swelling as well as polymer relaxation. [ABSTRACT FROM AUTHOR]

The effect of Mn on duplex stainless steel is of great importance in the development of lean duplex stainless steel. In this paper, we applied molecular dynamics simulations to quantitatively investigate the effect of Mn addition on the tensile behavior of ferritic/austenitic (bcc–fcc) iron duplexes as a model system for duplex stainless steels. We found that dislocations originate at grain boundaries and most of the initial dislocations in the grain boundaries are Shockley partial dislocations. The temperature and the number of dislocations conform to a normal distribution relationship. In addition, the tensile deformation mechanism of duplex stainless steel is dominated by both phase transformation and dislocation activity. Mn can improve the tensile properties of the material by delaying the arrival of plastic deformation, increasing the dislocation density to improve the strength of the model, and promoting the phase transformation mechanism of fcc → hcp → bcc. [ABSTRACT FROM AUTHOR]

Ferrites have excellent magnetic, electric, and optical properties that make them an indispensable choice of material for a plethora of applications, such as in various biomedical fields, magneto–optical displays, rechargeable lithium batteries, microwave devices, internet technology, transformer cores, humidity sensors, high-frequency media, magnetic recordings, solar energy devices, and magnetic fluids. Recently, magnetically recoverable nanocatalysts are one of the most prominent fields of research as they can act both as homogeneous and heterogenous catalysts. Nano-ferrites provide a large surface area for organic groups to anchor, increase the product and decrease reaction time, providing a cost-effective method of transformation. Various organic reactions were reported, such as the photocatalytic decomposition of a different dye, alkylation, dehydrogenation, oxidation, C–C coupling, etc., with nano-ferrites as a catalyst. Metal-doped ferrites with Co, Ni, Mn, Cu, and Zn, along with the metal ferrites doped with Mn, Cr, Cd, Ag, Au, Pt, Pd, or lanthanides and surface modified with silica and titania, are used as catalysts in various organic reactions. Metal ferrites (MFe2O4) act as a Lewis acid and increase the electrophilicity of specific groups of the reactants by accepting electrons in order to form covalent bonds. Ferrite nanocatalysts are easily recoverable by applying an external magnetic field for their reuse without significantly losing their catalytic activities. The use of different metal ferrites in different organic transformations reduces the catalyst overloading and, at the same time, reduces the use of harmful solvents and the production of poisonous byproducts, hence, serving as a green method of chemical synthesis. This review provides insight into the application of different ferrites as magnetically recoverable nanocatalysts in different organic reactions and transformations. [ABSTRACT FROM AUTHOR]

Fetal magnetocardiography (fMCG) has proven to be an important tool for the prenatal monitoring of electrical cardiac activity; however, the high cost of superconducting quantum instrumentation (SQUID) poses a limitation for the dissemination of fMCG as a routine clinical technique. Recently, optically pumped magnetometers (OPMs) operating within person-sized, cylindrical shields have made fMCG more practical, but environmental magnetic interference entering through the shield opening substantially degrades the quality of fMCG signals. The goal of this study was to further attenuate these interferences by placing the OPM array within a small ferrite shield. FMCG recordings were made with and without the ferrite shield in ten subjects inside a person-sized, three-layer mu-metal cylindrical shield. Although the fetal signal was slightly attenuated, the environmental interference was reduced substantially, and maternal interference was also diminished. This increased the signal-to-noise ratio significantly and improved the resolution of the smaller waveform components. The performance improvement was highest in the axial direction and compensated for a major weakness of open-ended, person-sized shields. The ferrite shield is especially beneficial for the deployment of triaxial OPM sensors, which require effective shielding in all directions. [ABSTRACT FROM AUTHOR]

Large single crystals of high-entropy oxides with the M-type hexaferrite structure, the chemical composition of which can be described by the formula BaFe12–x(Ti, Mn, In, Ga)xO19, are obtained for the first time by spontaneous crystallization from a solution. The actual compositions of the samples are determined: BaFe1.20Ti0.22Mn0.76In0.58Ga0.23O19, BaFe8.71Ti0.44Mn1.16In1.25Ga0.44O19, BaFe7.14Ti0.57Mn1.77In1.79 Ga0.73O19, BaFe5.6Ti0.64Mn2.48In2.52Ga0.76O19. These crystals have a special shape for hexaferrites and are characterized by a fairly uniform distribution of elements in their structure. A significant quantitative difference in the ability of various metal ions to transfer from a melt to a growing crystal is found. A change in the initial ion concentration in the solution has practically no effect on this ability. The influence of crystal compositions on their unit cell parameters is considered. Some increase in these parameters correlates with a decrease in the iron content in the samples. This is mainly due to an increase in the weighted average ionic radius of ions forming the crystals. The configuration mixing entropies within the sublattice formed by Fe, Ti, Mn, In, and Ga for the target compositions and the compositions of actually obtained crystals are calculated and compared. [ABSTRACT FROM AUTHOR]

Large single crystals of high-entropy oxides with the M-type hexaferrite structure, the chemical composition of which can be described by the formula BaFe12–x(Ti, Mn, In, Ga)xO19, are obtained for the first time by spontaneous crystallization from a solution. The actual compositions of the samples are determined: BaFe1.20Ti0.22Mn0.76In0.58Ga0.23O19, BaFe8.71Ti0.44Mn1.16In1.25Ga0.44O19, BaFe7.14Ti0.57Mn1.77In1.79 Ga0.73O19, BaFe5.6Ti0.64Mn2.48In2.52Ga0.76O19. These crystals have a special shape for hexaferrites and are characterized by a fairly uniform distribution of elements in their structure. A significant quantitative difference in the ability of various metal ions to transfer from a melt to a growing crystal is found. A change in the initial ion concentration in the solution has practically no effect on this ability. The influence of crystal compositions on their unit cell parameters is considered. Some increase in these parameters correlates with a decrease in the iron content in the samples. This is mainly due to an increase in the weighted average ionic radius of ions forming the crystals. The configuration mixing entropies within the sublattice formed by Fe, Ti, Mn, In, and Ga for the target compositions and the compositions of actually obtained crystals are calculated and compared. [ABSTRACT FROM AUTHOR]

Many sensitive atomic devices require magnetic shield to reduce external magnetic field interference. Mn–Zn ferrites are optimistic candidates for shielding because they provide a high shielding factor and a low magnetic noise. This study evaluated the magnetic noise of Mn–Zn ferrite magnetic shield based on its grain size. The morphologies of Mn–Zn ferrite samples were characterized to establish a correlation between their grain sizes and magnetic permeability, which can be used to calculate magnetic noises. The correlation was then used to evaluate the shielding performance of another Mn–Zn ferrite, where the magnetic noise of the magnetic shield made from the ferrite was calculated to be 2.53 f −1/2fT. The magnetic noise of the magnetic shield was also measured experimentally using a spin-exchange relaxation-free atomic magnetometer. The measured magnetic noise of ferrite shield was 2.61 f −1/2fT, while the white noise of the atomic magnetometer was 0.71 fT/Hz1/2 below 100 Hz. The consistency between the experimental results and predicted values suggests the viability of the proposed approach, providing a convenient, efficient, and precise method for developing ferrite ceramics materials for low-noise magnetic shields. [ABSTRACT FROM AUTHOR]

Experimental magnetic resonance spectra for nanometer ferrite brand 1SCh4 layer deposited on macroporous silicon substrate, obtained at T = 300 and 4.2 K in the frequency ranges of 5–15 and 60–75 GHz, respectively, were analyzed. In addition to the ferromagnetic resonance mode, additional peaks were found in the magnetoresonance spectra. An analysis using the known theoretical concepts of the modern spin dynamic theory, together with the results of micromagnetic simulation, showed the formation of spin-wave oscillation modes that arise due to the structurization of the ferrite layer by a substrate of macroporous silicon. [ABSTRACT FROM AUTHOR]

In this work a novel absorber that can operate simultaneously at the previous (P) and terahertz (THz) frequencies is proposed. This innovation features a single configuration composed of NiCuZnBi ferrite with periodic microstructure on the surface. In P band, the absorber achieves an absorption efficiency of more than 90 % (with a reflection loss of less than −10 dB) across the frequency range of 429.5 to 1000 MHz. This extremely low frequency absorption is solely attributed to the inherent magnetic loss of NiCuZnBi ferrite and is independent of the surface structure of the absorber. In the THz band, with this same absorber, a single layer of NiCuZnBi microstructure unit can achieve broad absorption range from 351.8 to 1200 GHz due to local energy loss caused by diffraction effects. More importantly, we have revealed the principle that increasing the number of NiCuZnBi microstructure unit layers is beneficial for broadening the THz absorption bandwidth. By designing stacked multi-layer structural units, we increased the absorption bandwidth of the device from 848.2 GHz for single-layer structures to 932.8 GHz for two-layer structures and 969.1 GHz for three-layer structures, respectively. The cross-band device design method proposed here makes it possible to develop electromagnetic absorbers that cover the P-band, THz band, and even more other frequency bands, thereby meeting the requirements of future applications such as multi-spectrum electromagnetic stealth and 6G communication. [ABSTRACT FROM AUTHOR]

Ferrite materials have the potential to become excellent absorbing materials due to their high magnetic loss and good impedance matching. However, the disadvantages of high density and lack of dielectric loss capability limit its application. Herein, we used the citric acid sol-gel method and the self-propagating combustion method to prepare neodymium-doped nickel-zinc ferrite (NZNF), then the target effect of Sn2+ and an improved electroless silver plating process was used to plate a layer composed of silver nanoparticles (Ag NPs) with strong dielectric loss on the NZNF, and a magnetic/dielectric composite material (NZNF@Ag) with a heterogeneous structure was prepared. The number and particle size of Ag NPs on the surface of NZNF can be precisely controlled, thereby greatly enhancing the dielectric loss capability with little impact on the magnetic loss. The huge difference in conductivity between conductors and semiconductors promotes the occurrence of polarization at the heterogeneous interface and significantly enhances the electromagnetic wave absorption ability of the composite material. In the 2–18 GHz frequency band, the best sample can obtain an effective bandwidth of 6.82 GHz when the matching thickness is 2.1 mm. Combining conductors with semiconductor materials to obtain significantly enhanced interfacial polarization provides a new idea for improving the performance of wave absorbing materials. [ABSTRACT FROM AUTHOR]

Ni0.53Cu0.12Zn0.35Fe2O4 ferrite powder is synthesized using the microwave‐assisted hydrothermal (M‐H) technique. The synthesized powder is characterized using X‐ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The morphology of the powder particles is examined using field effective scanning electron microscopy (FESEM). The powder is then sintered using microwave and conventional methods at 910°C/1.5 h and 910°C/4 h, respectively. The grain size, bulk density, d.c. resistivity, and saturation magnetization of both the sintered samples are measured and compared. The dielectric properties of both the sintered samples are measured at frequencies ranging from 1 MHz to 1.8 GHz. The research indicates that the sintering process has an impact on the magnetodielectric performance of ferrites. The change in properties resulting by the sintering method is briefly reviewed. [ABSTRACT FROM AUTHOR]

A simplified, fast, and effective production method has been developed for the synthesis of manganese ferrite (MnFe2O4) magnetic nanoparticles (MNPs). In addition to the wide applicability of MnFe2O4 MNPs, this work also reports their application in DNA isolation for the first time. An ultrasonic-cavitation-assisted combustion method was applied in the synthesis of MnFe2O4 MNPs at different furnace temperatures (573 K, 623 K, 673 K, and 773 K) to optimize the particles' properties. It was shown that MnFe2O4 nanoparticles synthesized at 573 K consist of a spinel phase only with adequate size and zeta potential distributions and superparamagnetic properties. It was also demonstrated that superparamagnetic manganese ferrite nanoparticles bind DNA in buffer with a high NaCl concentration (2.5 M), and the DNA desorbs from the MNPs by decreasing the NaCl concentration of the elution buffer. This resulted in a DNA yield comparable to that of commercial DNA extraction products. Both the DNA concentration measurements and electrophoresis confirmed that a high amount of isolated bacterial plasmid DNA (pDNA) with adequate purity can be extracted with MnFe2O4 (573 K) nanoparticles by applying the DNA extraction method proposed in this article. [ABSTRACT FROM AUTHOR]

The homojunction provides an effective way to extend the properties of stainless steel, but also leaves more weak points for small atoms to penetrate. In this study, the effects of hydrogen, carbon, and nitrogen atoms at the interface on the austenite/ferrite homojunction were investigated using first principles. This study found that low concentrations of carbon/nitrogen are favorable for the pairing of FCC with BCC compared to hydrogen, which can effectively improve the bonding energy and stability of homogeneous junctions. However, at high concentrations, the interfacial hydrogen can partially act as a mediator for interfacial bonding, which results in a slower decrease in bonding energy. On the contrary, nitrogen causes a sharp decrease in interfacial matching due to excessive strengthening of austenite, which reduces both the binding energy and the stability of the overall system. This study provides valid data and a unique perspective on the development of the austenite/ferrite homojunction. [ABSTRACT FROM AUTHOR]

Ferromagnetic materials such as the ferrites are used in the electronic and energy industries. Here, we concentrate on a complex Kraenkel-Manna-Merle system in a ferrite, under some coefficient constraints. An N-fold Darboux transformation of that system is presented via an existing Lax pair, where N is a positive integer. An N-fold generalized Darboux transformation, which admits one spectral parameter, is proposed through a limit procedure. One-, two- and three-soliton solutions of that system are determined via that N-fold Darboux transformation. The second-order and third-order degenerate soliton solutions of that system are derived via that N-fold generalized Darboux transformation. Those solitons are graphically represented for the magnetization and external magnetic field related to a ferrite. [ABSTRACT FROM AUTHOR]

In this paper, we describe the creation of a moderate band gap Nd-substituted Ni-Zn ferrite as a nano photo catalyst via a simple and cost-effective process of solution combustion. Nd substitution alters the crystallite size, shape, band gap, and magnetic characteristics of Ni-Zn ferrite significantly. Investigations using X-ray diffraction revealed that all samples display a pure phase. The average crystallite size was determined to be between 31.34 and 38.67 nm. On Nd doping, morphology investigations indicated that the shape of nanoparticles changed from approximately spherical to stacked grains. Band gap experiments confirmed the red shift in optical band gap on Nd doping. The synthesized catalysts Ni0.5Zn0.5Fe2O4 (Nd0), Ni0.5Zn0.45Nd0.05Fe2O4 (Nd1), and Ni0.5Zn0.5Nd0.05Fe1.95O4 (Nd2) have been effectively used for the degradation of methylene blue dye under the solar light irradiation. The sample with Nd substitution on Fe sites had the highest methylene blue degradation efficiency. Nd2 photo catalyst degrades the methylene blue dye with a degradation efficiency of 98% in 90 min of solar light irradiation. The photocatalytic activity is triggered by the existence of oxygen vacancies and a mixed valence state of Ni, Fe, and Nd, as confirmed by the XPS investigation. In addition, the investigations on scavenging reveal that the hydroxyl radical is a reactive component in the degradation process. The degradation route has been investigated in relation to the many potential reactions and discovered reactive substances. [ABSTRACT FROM AUTHOR]

This article presents a comprehensive investigation of the high-frequency magnetic flux distributions in manganese-zinc ferrite ring cores. New experimental characteristics are presented and used in the flux modeling. The flux distribution is predicted by a one-dimensional analytical model, a transmission-line model, and finite-element analysis. The models are used to investigate the high-frequency effects, such as skin depth and dimensional resonance. A complete experimental validation is presented. The nonuniform magnetic flux distributions are experimentally validated for two Mn-Zn materials: 3F36 and 3E10. The low permeability 3F36 material performance can be significantly degraded by dimensional resonance. However, the high permeability 3E10 material degrades due to the skin effect. The presented analytical methods show a very good correlation with the measurements. [ABSTRACT FROM AUTHOR]

Temperature- and humidity-sensing properties were evaluated of NixMg1-x spinel ferrites (0 ≤ x ≤ 1) synthesized by a sol-gel combustion method using citric acid as fuel and nitrate ions as oxidizing agents. After the exothermic reaction, amorphous powders were calcined at 700 °C followed by characterization with XRD, FTIR, XPS, EDS and Raman spectroscopy and FESEM microscopy. Synthesized powders were tested as humidity- and temperature-sensing materials in the form of thick films on interdigitated electrodes on alumina substrate in a climatic chamber. The physicochemical investigation of synthesized materials revealed a cubic spinel F d 3 ¯ m phase, nanosized but agglomerated particles with a partially to completely inverse spinel structure with increasing Ni content. Ni0.1Mg0.9Fe2O4 showed the highest material constant (B30,90) value of 3747 K and temperature sensitivity (α) of −4.08%/K compared to pure magnesium ferrite (B30,90 value of 3426 K and α of −3.73%/K) and the highest average sensitivity towards humidity of 922 kΩ/%RH in the relative humidity (RH) range of 40–90% at the working temperature of 25 °C. [ABSTRACT FROM AUTHOR]

The magnetization of cobalt ferrite nanocubes of similar size, but with varying Co/Fe ratio, is extensively characterized on atomistic and nanoscopic length scales. Combination of X‐ray diffraction, Mössbauer spectroscopy, magnetization measurements and polarized small‐angle neutron scattering (SANS) reveals that a lower amount of cobalt leads to an enhanced magnetization. At the same time, magnetic SANS confirms no or negligible near‐surface spin disorder in these highly crystalline, homogeneously magnetized nanoparticles, resulting in an exceptionally hard magnetic material with high coercivity. [ABSTRACT FROM AUTHOR]

Manganese–zinc (Mn-Zn) ferrites are the primary choice for high-frequency and high-power magnetic components. Optimum material selection is essential for high-performance magnetic component design. However, the manufacturers’ material specifications usually do not provide sufficient information to optimize the design. Complex permeability and permittivity, as well as specific power loss, are typically provided as one value, regardless of the core shape and size. Magnetic component design based on these incomplete specifications can result in a poorly optimized component. This article proposes methods to determine the properties of Mn-Zn ferrite at high frequencies, with tests up to 20 MHz. This article also presents experimental complex permeability and permittivity frequency characteristics for four ferrite materials: 3E10, 3F36, 3E65, and 3C95. The resulting fitted parameters for the equivalent-circuit model can be used in any design algorithm or simulation tool. The impacts of physical size, temperature and force on complex permeability and permittivity are also considered. [ABSTRACT FROM AUTHOR]

Copyright of Steel Pipe is the property of Steel Pipe Magazine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

With the extensive application of electrical and wireless equipment, several electromagnetic pollution‐related issues have emerged. Therefore, the manufacturing of absorbing materials has become important to electromagnetic pollution. Ferrite is a common absorbing material; its single absorbing mechanism and narrow absorbing frequency band resist the wider usage as an ideal absorbing material. Adding different materials to ferrite has become a popular way to enhance its microwave absorption properties. Herein, the recent research on ferrite multicomponent microwave absorbing composites is summarized. For ferrite binary composite absorbing materials, the research progress of ferrite and graphene, carbon nanotubes, carbon fiber and other carbon materials, ferrite and polypyrrole, polyaniline and other polymer materials, and ferrite and MXene composites is introduced. In addition, the advancement of ferrite ternary absorbent materials research is also discussed. The growing development trend of ferrite composite absorbing materials is finally summed up, and the prospects of fabricating the "thin, light, wide, and strong" ferrite absorbing materials are put forward. [ABSTRACT FROM AUTHOR]

Three-dimensional electromagnetic imaging can be used to monitor grain within metallic grain bins. Data acquisition requires multiple antennas surrounding the imaging space, which are used to transmit and receive the electromagnetic energy inside the bin. Due to their presence inside a metallic enclosure and due to very large mechanical forces these antennas are required to be low profile. In addition, since they are part of the imaging domain, they should be simple to model in the imaging software (i.e., using a point source). Existing half-loop magnetic field antennas meet these design criteria, but can be improved, particularly with better radiation efficiency. Herein, we present an enhanced antenna design: a ferrite-loaded shielded half-loop antenna designed to measure only the tangential component of the magnetic field against the metal enclosure wall, while rejecting the normal component of the electric field. Experimental results in two bins show that the enhanced design improves the signal level over existing probes by 6–18 dB inside a small-scale enclosure and around 20 dB inside a larger 28 m 3 (800 bushel) bin. Full 3D imaging results of a high-moisture target within a low-moisture grain background inside the test enclosure show that the enhanced antennas improve the quality of the reconstructed results in the smaller bin, particularly where the antenna performance improvements are prominent. [ABSTRACT FROM AUTHOR]

Power electronic transformers (PETs) have attracted extensive attention in the fields of renewable energy and energy storage, and ac/dc hybrid distribution systems. This article analyzes the vibration generation and conduction of the high-frequency transformer, which is a key component of the PET. An experimental study is presented on the vibration characteristics of a ferrite transformer under different switching frequencies and phase-shift modulation methods. What is more, based on the three vibration sources of the transformer, a quantitative mathematical description between the core vibration acceleration and the excitation voltage and current is obtained under different phase-shifting modulation modes. The errors between the numerical calculated values and the experimental data are basically within 10%, which verifies the validity of the research and prediction of PETs vibration characteristics under different modulation modes. [ABSTRACT FROM AUTHOR]

Nickel-copper ferrite nanoparticles NixCu1-x Fe2O4 with values x = 0.3, 0.5,0.7 fabricated by combustion method. X-ray diffraction (XRD) analyzes confirmed the formation of the ferrite structure. The average size of crystals was estimated to range from 39 to 44 nm. The particle morphology was detected and interpreted by the FSEM scanning microscope and the porosity characteristic of the ferrite structure based on the combustion method was observed. The FTIR analysis was performed to investigate the bonds in which the tensile vibrational mode of the tetrahedral site in the range of the wavelength of 500–600 cm−1.The magnetic properties of nanoparticles were investigated using VSM analysis and the effect of increasing of copper ion on MS saturation magnetization and HC coercivity force was investigated. With respect to the saturation magnetization values for the synthesized samples, it was observed that by increasing the Cu content from x =.3 to x =.5 the saturation magnetization decreased and then increasing with increasing Cu content such that at x =.5, we had the lowest saturation magnetism. Reduction of saturation magnetization Copper ions occupy ferric ions in tetrahedral sites and iron ions are transferred to octahedral sites. The results of UV–Vis indicate to complete absorption in the samples. The linearity of the edge of the absorption spectrum relates to a direct energy band gap and the effect of increasing copper ions on ferrite conductivity was investigated. [ABSTRACT FROM AUTHOR]

The Ni-Al ferrite nanoparticles are synthesized by the flash auto-combustion method, and PANI is synthesized by the situ-chemical oxidative polymerization method. NiAl-ferrite/PANI/ x (PANI) Nanocomposite Films (x = 0.6 and 0.8) were prepared using a solution casting process. The X-ray results of the NiAlxFe2-xO4/PANI composite manifest that the Ni-Al ferrite fully interacted with PANI molecules and the Ni-Al ferrite particles are embedded in the PANI chains from TEM and SEM images. The dielectric parameters ϵ′, ϵ″ and tan δ decreased with the increase in the frequency of the applied field. The modulus M″ spectra of the investigated samples show two relaxation peaks in two frequency regions. In Cole–Cole plot of M′ versus M″, a semicircular trend is observed, i.e. a non-Debye criterion. The presence of PANI in the NiAl0.6Fe1.4O4/PANI composite films reduces the magnetic properties of the composite samples leading to the decrease of saturation magnetization and remanence magnetization. [ABSTRACT FROM AUTHOR]

This study deals with the evaluation of the catalytic activity of quaternary nickel‐zinc‐cobalt ferrite (NiZnCoF) nanoparticles on the thermal decomposition of 3‐nitro‐2,4‐dihydro‐3H‐1,2,4‐triazol‐5‐one (NTO). Nanosize NiZnCoF has been successfully synthesized using the co‐precipitation method. The effect of 5% by mass NiZnCoF on the thermolysis of NTO and NTO with nanosize (nNTO) has been studied using simultaneous thermal analysis. In the presence of NiZnCoF additive, the decomposition of NTO and nNTO was increased by 8.55 and 7.68°C, indicating that the additive stabilizes NTO and nNTO. The DSC peak temperature also suggests the presence of NiZnCoF decreases the nNTO's exothermic curve by 5.62°C. The DSC peak curve of NTO in the presence of NiZnCoF was shifted from 276.35 to 272°C. The activation energy calculations suggested that the high activation energy of NTO can be reduced ∼82–87 kJ mol−1 by nanosizing NTO followed by the incorporation of NiZnCoF. [ABSTRACT FROM AUTHOR]

A low-profile and wideband unidirectional antenna with ferrite loading is presented for ultrahigh-frequency (UHF) applications. This design comprises a slotted bowtie antenna with parasitic elements placed 50 mm over a ground plane. A small amount of ferrite loaded on the center of the ground plane plays a crucial role in improving the performance of the low-profile antenna. The ferrite used here is a new type of magnetodielectric material with relatively high permeability and permittivity, as well as low magnetic and dielectric loss. The loaded ferrite introduces an additional phase change of the electromagnetic field reflected by the ground to improve the impedance matching, bandwidth, efficiency, and gain of the low-profile antenna. The evolution process and mechanism of the proposed antenna are elaborated. For validation, an optimized antenna prototype was fabricated and measured. The measured results are consistent well with their simulations, which shows the realized gain of 7.2–9 dBi over $\vert \text{S}_{11}\vert \le -10$ dB impedance bandwidth of 38% (480–705 MHz). The overall profile of this antenna is only $0.08\lambda _{0}$ , where $\lambda _{0}$ is the free-space wavelength at the lowest frequency of operation. [ABSTRACT FROM AUTHOR]