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In this work, CFO/MWCNTs/PVDF and BFO/MWCNTs/PVDF composites are prepared and the comparative analysis of electrical properties and electromagnetic interference (EMI) shielding performance of both type of composites are investigated. The dielectric and conductivity characteristics are observed with varying ferrite concentration, frequency, and temperature. Ferroelectric properties are also obtained at 6 kV/cm field and EMI shielding behavior is observed in 8–12 GHz frequency range. Results exhibited that the studied properties of the composite enhances with increasing ferrite concentration that attributed to increased amount of magnetic nanoparticles. Cobalt ferrite (CFO) filled polyvinylidene fluoride (PVDF) composite is showing better properties as compared to barium ferrite (BFO) filled PVDF composites. The mechanism involve for this behavior is discussed herein. [ABSTRACT FROM AUTHOR]

The transition from external to internal oxidation of a binary Fe-10Cr alloy has been investigated in Fe/FeO Rhines pack (RP) and H2/H2O between 850 and 900 °C. Internal oxidation is facilitated by increasing temperature and presence of water vapor. A classical Wagnerian diffusion analysis predicts external oxidation for ferritic (BCC) Fe-10Cr and internal oxidation for austenitic (FCC) Fe-10Cr. The α-to-γ transformation is demonstrated to be the primary factor promoting internal oxidation in Fe–Cr around 900 °C. Water vapor is believed to promote internal oxidation due to a higher reactivity of H2O compared to O2 and higher preferential adsorption of the H2O molecule. [ABSTRACT FROM AUTHOR]

This study investigates Beam Line Absorbers (BLAs) for the Hefei Advanced Light Facility (HALF). A ferrite-based BLA prototype was developed, demonstrating high-power handling capacity up to 10 kW, ultra-high vacuum performance better than 6. 5 × 1 0 − 1 0   mbar, and high absorption efficiency in critical frequency ranges. Subsequently, more compact designs with reduced longitudinal length were explored, investigating ferrite-only, silicon carbide (SiC)-only, and hybrid configurations through RF simulations. Based on preferred absorption efficiency, ferrite-only and hybrid BLA structures were further analyzed under high-power conditions. Referencing test results, multiphysics simulations were conducted under 3 kW absorbed power. The hybrid design, comprising two rings of ferrite tiles and one ring of SiC tiles, improved the temperature distribution of the absorbing materials. Extrapolating to 11 kW absorbed power, this design reduced the maximum temperatures on absorbing tiles by up to 40 ° C compared to the ferrite-only design. The hybrid design offers a balanced solution that combines effective HOM damping with enhanced thermal performance, improving the long-term operational stability of BLAs. [ABSTRACT FROM AUTHOR]

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]

The dominant treatment process for removing heavy metals from industrial wastewater is chemical neutralisation precipitation using lime milk as a precipitation agent, resulting in a highly voluminous hydroxide sludge with a low heavy metal concentration. These sludges are predominantly landfilled, and the metals are lost to the circular economy. At the same time, metals are urgently needed as raw materials. A new approach is represented by the low-pressure, low-energy Specific Product-Oriented Precipitation process (SPOP). This approach, however, requires the adjustment of various reaction parameters for optimal operation. This study presents the impacts of the stirring rate during the reaction and the Fe concentration in the solution on the recovery of Cu from Cu-enriched electroplating wastewater. Three different recovery options are described: Option (1), the formation of CuO; Option (2), the generation of brochantite, a Cu-hydroxysulphate; and Option (3), the incorporation of Cu into ferrite. Tenorite (CuO) is precipitated at 40 °C reaction temperature at a low stirring rate of 100–200 rpm. At an accelerated stirring rate of 400–500 rpm, brochantite (Cu4(OH)6SO4) is formed. With high Fe concentrations and a molar ratio of Cu:Fe of 1:2, Cu-ferrite (CuFe2O4) is the precipitation product. In any case, the achieved recovery rates in the treated wastewater are better than 99.9%. [ABSTRACT FROM AUTHOR]

Zinc-substituted cobalt ferrites were obtained by a green method using a black grape extract as a reductant and fuel. XRD analysis confirmed the spinel structure of the synthesized ferrites. An increase in the lattice constant is explained by increased Zn content. SEM analysis confirmed changes in surface morphology, whereas FTIR spectra demonstrated the presence of organic species in the samples, which originated from grape extract. The content of Co(II) ions in octahedral sites as a function of the ratio between Fe(III) ions in A- and B-sites was calculated from Mössbauer data. pHPZC rose from 7.85 to 8.13 with an increase in zinc content, indicating a positive charge of the adsorbent surface at natural pH. The adsorption–catalytic properties of the spinel samples were investigated in terms of Congo Red (CR) dye removal. The mechanism of CR adsorption on the ferrite surface includes electrostatic and donor–acceptor interactions with the adsorbent surface. Furthermore, the sample with x(Zn) = 0.4 exhibited the highest degradation rate constant k = 0.102 min−1 in the peroxide oxidation of CR, whereas the sample with x(Zn) = 1.0 exhibited the highest adsorption capacity. The electron transfer between ferrite samples and hydrogen peroxide was evidenced using electrochemical tests. The green-synthesized Co-Zn ferrites demonstrate a big potential as adsorbents/catalysts for water treatment. [ABSTRACT FROM AUTHOR]

In the current work, MnxZn1−xLa0.1Fe1.9O4 ferrite nanoparticles were prepared using a solid-state reaction, with x values of 0, 0.1, 0.3, 0.5, 0.7, and 1. The structure, morphology, optical, magnetic, and dielectric characteristics of the prepared samples were characterized using X-ray Diffraction (XRD), Fourier Transformed Infrared Spectrometer (FTIR), Scanning Electron Microscopy (SEM), UV-Vis spectrophotometer, Vibrating Sample Magnetometer (VSM) and impedance analyzer. XRD and FTIR spectra assured the formation of the cubic spinel phase structure as well as tetrahedral and octahedral bonding in the synthesized samples. SEM analysis of the surface morphology revealed irregular and semi-spherical shapes. The prepared samples' elements were confirmed to be present based on their chemical composition by the EDX analysis. The Kubelka-Munk function was used to calculate the optical band-gap energy Eg based on the near-infrared (NIR) and visible (VIS) reflectance spectra, which are dependent on Mn dopant ion concentration. The VSM findings demonstrate that the characteristics of the samples transformed gradually from antiferromagnetic to ferromagnetic behavior with increasing Mn content. The dielectric results exhibit that the doping of Mn ions decreases the dielectric constant and dielectric loss and increases the resistivity. The physical properties of MnxZn1−xLa0.1Fe1.9O4 nanoparticles, such as their low power losses, coercivity, high resistivity, permittivity, and saturation magnetization, make them suitable for many applications, from biomedical to electronic devices. [ABSTRACT FROM AUTHOR]

Optical vortex induced forward transfer (OV-LIFT) allows the crystallization of magnetic nanoparticles enabling the fabrication of a 2-dimensional array of monocrystalline structures with a high spatial resolution. We herein investigate the optimum experimental conditions, such as the viscosity range of the donor and the energy range of the optical vortex pulse required for the crystallization of magnetic nanoparticles through a cavitation processes, including the flight dynamics of donor. [ABSTRACT FROM AUTHOR]

Ferrite has been extensively studied due to its wide range of applications. In present work, Li0.4-0.5xZn0.2Mn0.1Mgx-0.1Fe2.4-0.5xO4 (x = 0.1, 0.15, 0.2, 0.25, 0.3) were synthesized by sol-gel auto-combustion method. X-ray diffraction and infrared spectroscopy confirmed the formation of a cubic spinel structure. The lattice constant was found to increase with higher x values, while density, grain size and microstrain decreased correspondingly. The saturation magnetization and coercivity showed slight decreases after Mg doping, whereas the initial permeability slightly increased. The Curie temperature declined from 433 °C at x = 0.1 to 395 °C at x = 0.3. Mg doping also reduced the optimal matching thickness of microwave-absorbing materials to 3 mm. Mg-LiZnMn absorber is lighter in weight than LiZnMn. Notably, the sample with x = 0.15 exhibited excellent absorption characteristics from 8.2 GHz to 13.1 GHz, with a reflection loss (RL) of −32 dB. These findings suggest that an appropriate concentration of Mg doping can enhance the impedance matching of the materials, thereby improving their microwave absorption performance. Highlights: Mg doping can improve the initial permeability of LiZnMn ferrite. Mg doping can reduce the best matching thickness to 3 mm, proper concentration can improve microwave absorption ability of materials. Resonance peaks were observed in permittivity spectra of Mg-doped LiZnMn ferrites. [ABSTRACT FROM AUTHOR]

Herein, sol gel method was used to prepare titania coated manganese ferrite nanocomposite (TMFN) for wastewater treatment. The prepared TMFN nanocomposite was characterised using FTIR, SEM XRD, VSM, EDX, and BET techniques. The characterisation studies confirmed the formation of the nanocomposite and gave good information about its morphology. Batch adsorption method was applied to determine the optimal adsorption conditions towards Cu(II) and Pb(II) ions. The studied parameters were pH of the solution, contact time, adsorbent amount, initial concentration of ions and temperature. After finding out and applying the optimal adsorption conditions, maximum adsorption capacities of 550 and 460 mg/g were achieved for Cu(II) and Pb(II) ions, respectively. Isotherm and kinetic studies revealed that the current adsorption process is fitted well by Langmuir isotherm and pseudo-second order model. Thermodynamic investigations showed that the adsorption process is energetically favourable and takes place spontaneous with positive enthalpy change. Furthermore, the ability to regenerate and reuse the adsorbent confirmed its sustainability. The prepared nanocomposite could be reused many times with no significant loss in adsorption capacity. [ABSTRACT FROM AUTHOR]

The calcium ferrite nanoparticles were made by the sol–gel process. X-ray diffraction, a scanning electron microscope, and UV–vis spectroscopy were used to analyze the material. There is an orthorhombic phase in the space group Pnma. There were four techniques used to calculate the average crystallite size. Using ImageJ software, the particles were aggregated and their size was ascertained. Using energy-dispersive X-ray (EDX) analysis, the composition of the material was ascertained. 2.29 eV was determined to be the band gap. Vibrating test magnetometer (VSM) provided an explanation for the materials' magnetic property. A decreased band gap energy is responsible for the 90% degradation of malachite green dye at a concentration of 15 mg/L in 150 min, with a four-cycle reusability. HIGHLIGHTS: Calcium ferrite nanoparticles were successfully synthesized by sol–gel assisted combustion method using leaf extract of Brassica oleracea as fuel. To the best of the author's knowledge, no such case study that reports the synthesis of calcium ferrite nanoparticles by using leaf extract of Brassica oleracea is previously reported in academic literature. The method is cost-effective and convenient without the use of any chemical fuel agents. The synthesized prepared material efficiently removes malachite green dye, commonly used in industries for dyeing silk and nylon, from the solution. More than 90 % removal efficiency for MB. The material displayed excellent stability and reusability for dyes adsorption. Results were validated with pseudo-first-order kinetic model. [ABSTRACT FROM AUTHOR]

This review discusses the synthesis, characterization, catalytic applications, mechanisms, current advances, challenges, and environmental consequences of Graphene oxide-based ferrite nanocomposites. The synthesis described the strategies used to synthesize these nanocomposites. The structural characterization was discussed using XRD, FTIR, and Raman spectroscopy techniques and how it could learn about their chemical composition and bonding. Morphological characterization said the results obtained on the nanostructure of these nanocomposites. The catalytic application phase is concerned with their use in photocatalysis, electrocatalysis, and magnetic catalysis, as well as the synergistic impact and the extra suitable electron switch pathways. The assessment also highlighted emerging developments in synthesis, novel catalytic applications, and capacity applications. The challenges and destiny directions discussed the importance of particular synthesis, management, balance, enhancement, and scalability. Compared to the sustainability, economic viability, and ecological effect, the environmental and monetary issues section underlined the significance of environmentally pleasant manufacturing and massive-scale viability. [ABSTRACT FROM AUTHOR]

Cobalt-doped bismuth ferrite (Bi1-xCoxFeO3) nanoparticles (NPs) at x = 0.00, 0.03, 0.07 were synthesized using the sol–gel auto-combustion method and studied the influence of cobalt (Co) on structural, surface, chemical, optical, magnetic, and photocatalytic properties on Bi1-xCoxFeO3 nanoparticles. X-ray diffraction (XRD) studies revealed the rhombohedral structure of the synthesized nanoparticles with a mean crystallite size of 51 nm. Using Tauc’s relation, the optical band gap was calculated, and it decreased from 2.13 to 1.6 eV with increased Co concentration. The iron-oxygen (Fe–O) stretching vibrations were confirmed from Fourier transform infrared (FT-IR) spectra. Magnetic properties of the nanoparticles were studied using a vibrating sample magnetometer and found that Bi1-xCoxFeO3 nanoparticles are ferromagnetic at room temperature. The strength of magnetization increased with an increase of Co doping concentration. Photocatalytic properties of the Bi1-xCoxFeO3 nanoparticles were studied using a UV–Vis-NIR spectrophotometer, and it was found that Bi1-xCoxFeO3 nanoparticles can be used as a photocatalyst in the visible region of the spectrum. Methyl blue (MB) dye was used to study the dye degradation property of pure and Co-doped BiFeO3 nanoparticles, and the results were explained in detail. The Bi1-xCoxFeO3 nanoparticles at x = 0.07 exhibited the highest photocatalytic activity (97.9%). [ABSTRACT FROM AUTHOR]

With the booming development of electronic information science and 5G communication technology, electromagnetic radiation pollution poses a huge threat and damage to humanity. Developing novel and high-performance electromagnetic wave (EMW) absorbers is an effective method to solve the above issue and has attracted the attention of many researchers. As a typical magnetic material, ferrite plays an important role in the design of high-performance EMW absorbers, and related research focuses on diversified synthesis methods, strong absorption performance, and refined microstructure development. Herein, we focus on the synthesis of ferrites and their composites and introduce recent advances in the high-temperature solid-phase method, sol–gel method, chemical coprecipitation method, and solvent thermal method in the preparation of high-performance EMW absorbers. This review aims to help researchers understand the advantages and disadvantages of ferrite-based EMW absorbers fabricated through these methods. It also provides important guidance and reference for researchers to design high-performance EMW absorption materials based on ferrite. [ABSTRACT FROM AUTHOR]

The Cu2+ ion-substituted Ni-Zn ferrites were synthesised by the citrate gel auto-combustion method. The structural and micro-structural analyses of all samples were done using XRD and SEM, respectively. XRD studies confirmed that all samples belong to a cubic spinel structure. The cation distributions of all samples were estimated using relative X-ray intensity calculations. Room temperature, temperature variation, electrical resistivity, initial permeability and dielectric properties were carried out by an impedance analyser. The dielectric and permeability values decreased with increasing frequency. The addition of Cu2+ ions in the present system modifies the cation distribution which results in a gradual decrease of magnetisation values. The temperature dependence of initial permeability showed a sharp decrease with increasing temperature. This indicates the formation of a single phase of materials. The maximum permeability value obtained at x = 0.10 is directly related to the grain size. These temperature variation studies indicate that all these materials are well-suitable for MLCI applications. [ABSTRACT FROM AUTHOR]

This paper presents the preparation of Al‐doped mixed transition metal ferrite (AlxCo0.7Mn0.3Fe2−xO4 where x=0.1, 0.3, 0.5, 0.7 and 0.9) via a solution combustion method, followed by an application for the removal of dyes from aqueous solution. Various physicochemical techniques were employed to determine the morphological, structural, magnetic behaviour and adsorption characteristics of the synthesized ferrites by through Scanning Electron Microscope (SEM), X‐ray powder Diffraction (XRD), Fourier Transform Infra‐Red spectroscopy (FT‐IR), Vibrating Sample Magnetometer (VSM), and Brunauer‐Emmett‐Teller (BET) analysis. Furthermore, the as‐synthesized ferrite materials were utilized for adsorbing dyes (Methylene blue (MB), Crystal violet (CV), Methyl orange (MO), and Congo red (CR)) from aqueous solutions, with the results reported using UV‐visible spectroscopy. The findings indicate that Al‐doped mixed transition metal ferrites serve as potential adsorbents for dye removal. [ABSTRACT FROM AUTHOR]

Spinel ferrites demonstrate extensive applications in different areas, like electrodes for electrochemical devices, gas sensors, catalysts, and magnetic adsorbents for environmentally important processes. However, defects in the real spinel structure can change the many physical and chemical properties of spinel ferrites. Although the number of defects in a crystal spinel lattice is small, their influence on the vast majority of physical properties could be really decisive. This review provides an overview of the structural characteristics of spinel compounds (e.g., CoFe2O4, NiFe2O4, ZnFe2O4, Fe3O4, γ–Fe2O3, Co3O4, Mn3O4, NiCo2O4, ZnCo2O4, Co2MnO4, etc.) and examines the influence of defects on their properties. Attention was paid to the classification (0D, 1D, 2D, and 3D defects), nomenclature, and the formation of point and surface defects in ferrites. An in-depth description of the defects responsible for the physicochemical properties and the methodologies employed for their determination are presented. DFT as the most common simulation approach is described in relation to modeling the point defects in spinel compounds. The significant influence of defect distribution on the magnetic interactions between cations, enhancing magnetic properties, is highlighted. The main defect-engineering strategies (direct synthesis and post-treatment) are described. An antistructural notation of active centers in spinel cobalt ferrite is presented. It is shown that the introduction of cations with different charges (e.g., Cu(I), Mn(II), Ce(III), or Ce(IV)) into the cobalt ferrite spinel matrix results in the formation of various point defects. The ability to predict the type of defects and their impact on material properties is the basis of defect engineering, which is currently an extremely promising direction in modern materials science. [ABSTRACT FROM AUTHOR]

In this paper, BaFe12O19/Ni0.5Mn0.5Fe2O4@PANI core‐shell nanocomposites were synthesized with different ferrite/PANI ratios. The Ferrite nanoparticles were prepared by the auto‐combustion sol–gel method. Chemical oxidative polymerization of aniline in acidic solution along with adding ferrite nanoparticles to the composition was used for the synthesis of nanocomposites. The product then was studied by X‐ray diffractometer)XRD(, field emission scanning electron microscope (FE‐SEM), transmission electron microscope (TEM), and Fourier transform infrared spectroscopy (FTIR) analyses. The magnetic properties of samples were investigated with vibrating sample magnetometer (VSM). Also, nanocomposite samples were examined in terms of the ability to absorb microwaves. Using Vector Network Analyzer (VNA). the reflection loss (RL) of nanocomposites was measured at frequencies between 2 and 18 GHz. The minimum reflection loss (RLmin) was obtained at −36.98 dB at the frequency of 13.8 GHz with an effective absorption bandwidth of 4.87 GHz for the sample with the equal ratio of ferrite/PANI. Synthesized nanocomposite as an effective compound has very high reflection loss in a wide frequency range. Highlights: Thermal stability is improved by adding ferrite nanoparticles to polyaniline.The polymer shell reduces the magnetic properties of ferrite nanoparticles.There is a strong exchange coupling between hard and soft ferrite.Ferrite/polymer ratio of 1:1 has the lowest amount of reflection loss.In the X and Ku band, magnetic loss is mainly caused by eddy currents. [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]

Coconut coir-based porous carbon (CCPC) and magnetic iron (Fe) particle composite (CCPC/Fe) have been developed and characterized for potential applications in unmanned aerial vehicles (UAVs). Coconut coir was extracted from coconut husks and Fe compounds are impregnated to form CCPC/Fe. A comprehensive analysis was conducted, encompassing XRD analysis, revealing the presence of crystalline Fe particles and amorphous carbon, with broadened peaks and a crystalline size of 16.68 nm. Raman spectroscopy showed distinctive structural properties. UV-Vis spectroscopy exposed unique absorption peaks and SEM imaging confirmed the retention of porous structures and the successful integration of Fe particles. EDS analysis provided insights into the elemental composition, emphasizing the varying compositions of the sample. The VNA testing reflection loss value of -26 dB (2 mm thick sample) calculated from VNA testing indicated EM wave attenuation of > 99 %. These results underscores the potential of CCPC/Fe, making it an attractive candidate for advanced applications like EM wave attenuation in UAVs. The research contributes to materials science by offering a sustainable, cost-effective solution to enhance electromagnetic compatibility in UAVs, ensuring dependable and secure operation across diverse environments. [ABSTRACT FROM AUTHOR]

In this paper, a ferrite-filled rectangular waveguide as a balanced composite right/left-handed (CRLH) transmission line is considered. Based on the surface current density of dominant mode, a centerline longitudinal slot on the broad wall of this ferrite-filled rectangular waveguide can be radiate to the free space as a leaky-wave antenna (LWA). This proposed LWA has the both capability of the fixed-bias frequency scanning and fixed-frequency bias scanning from negative to positive angles. However, the gain of the centerline slotted ferrite-filled rectangular waveguide antenna is not acceptable. By adding another slot and changing the position of slots on the broad wall, the gain is improved to more than 9 dB in frequency range of 6.59–6.69 GHz. [ABSTRACT FROM AUTHOR]

In this research copper tagged magnetic surface imprinted polymer (IIP) has been developed using 1,10-phenanthroline immobilized magnesium ferrite–starch. Maximum removal of 95% was achieved at the optimum conditions i.e., 10 min contact time, pH of 6, and IIP amount of 20 mg. According to the kinetic study copper adsorption followed pseudo-second-order model moreover, based on the isotherm study Freundlich model better described the adsorption process as the maximum adsorption capacity of 33.7 mg g−1 was achieved. Adsorbed copper ions were eluted from the adsorbent surface with an HCl solution (0.5 mol L−1) and the IIP exhibited appropriate reusability (removal of more than 92%) after four cycles of sorption and elution. The limit of detection, linear dynamic range and RSD were 0.5 and 3.0–100 µg L−1 and 3%, respectively. The copper-tagged IIP showed a selectivity factor of 8.8, 4.6, 3.3, 3.2 and 5.4 concerning Zn, Ni, Co, Mn and Cd, respectively. The developed IIP-based adsorption system was employed for copper adsorption/preconcentration from water and food samples with an efficiency more than of 95%. Results confirmed that the IIP system is an appropriate route to reduce the side effects of heavy metals in aqueous media. [ABSTRACT FROM AUTHOR]

Microwave applicators reported for intracavitary hyperthermia (HT) operate at single frequency and deliver fixed treatment coverage at the tumor target. In this work, we report multifrequency operation of a water-cooled monopole antenna with a sliding broadband ferrite choke for delivering intracavitary HT to the cervix with variable spatial coverage. Spatially varying treatment coverage is achieved by varying the choke position with respect to the monopole using a mechanical sliding arrangement and exciting the antenna at the modified resonant frequency. Multifrequency operation of the antenna prototype is demonstrated over 700–1000 MHz using a straight intrauterine cervix applicator. Numerical simulations confirm the ability to deliver targeted HT with axial extent varying between 35.4 and 62.0 mm by controlling the sliding choke and coupling water temperature. Applicator prototype measurements in tissue mimicking phantoms confirm multifrequency operation of the antenna and its ability to induce axially varying intracavitary HT coverage to match the tumor size using a single applicator. Plain-language summary: Microwave devices used for targeted internal hyperthermia treatment typically operate at fixed frequency and provide fixed treatment coverage to the tumor. In this study, we introduce a new approach using a water-cooled monopole antenna with a sliding broadband ferrite choke to treat cervical cancer with varying tumor volumes. The proposed antenna can be operated at multiple frequencies to adjust the treatment volume. By sliding the choke along the antenna, the antenna can be tuned to different frequencies and deliver spatially varying treatment coverage to suit the clinical target volume. Laboratory assessment shows that this antenna can be operated over 700 to 1000 MHz to deliver treatment coverage with axial extent varying over 35.4 to 62.0 mm, depending on the choke position and water temperature. Experiments on tissue mimicking phantoms confirm that this method enables precise control of hyperthermia treatment coverage to match the tumor size using a single device. [ABSTRACT FROM AUTHOR]

This research article was investigates the Prussian blue dye removal from aqueous solution using immobilized nano ferrite (Zn-Co-Fe) in alginate biopolymer. The preparation of alginate beads was done by metal encapsulation method using CaSO4 as crosslinking agent. The Prussian blue dye removal efficiency was ascertained with various isotherm equations such as Langmuir and Freundlich. Isotherm equations are not providing physical, chemical and feasibility aspects. So, these were investigated with pseudo-first order, pseudo-second order kinetic equations. The mode of diffusion evaluated with intraparticle diffusion and thermodynamic feasibility was tested with the equations of enthalpy, Gibbs free energy, and entropy. The experimentally driven results were implies the Prussian blue removal process was feasible in all aspects. Moreover, the predicted diffusion parameters revealed that the interaction between Prussian blue and nanocomposite beads was predominant. The surface morphology, examined using a Scanning Electron Microscope, showed that the Prussian blue strongly covered on outer surface of the beads. The FTIR proves the Prussian blue dye was strappingly loaded on the surface of nanocomposite beads. The TGA curve revealed the synthesized beads has an exceptional temperature resistance. [ABSTRACT FROM AUTHOR]

Search for water-stable, low-cost materials for sustainable water treatment is on the rise. Recently, phyto-magnetic hybrid materials have been demonstrated as the promising ones, showcasing outstanding water treatment capability, albeit challenging to prepare. Herein, we report the synthesis of peanut shell-embedded magnetic ferrites (MPS) for the scintillating elimination of crystal violet (CV) dye from a series of simulated, spiked, and wastewater. FTIR, FESEM-EDX, VSM, PXRD, and pHZPC elucidate the material characteristics, and CV uptake was mapped concerning various physicochemical parameters like equilibration time (0–90 min), pH (3–11), temperature (298–328 K), ionic strength, and competitive inhibition thwarting from coexistent ions. FTIR suggests the presence of polyphenolic moiety (3428 cm−1) and carbonyl groups (1716 cm−1). FESEM reveals a porous structure with uneven fractures which upon CV uptake converts to a smoother one. Vibrating sample magnetism suggests a typical hysteresis for a soft magnetic material with a saturation magnetization value of 28.464 emu/g and coercivity of 35.240 Oe. The maximum intake capacity is 97.903 mg/g at 298 K, whereas the process follows pseudo-second-order kinetics (R2 = 0.999) and the Langmuir isotherm model (R2 = 0.996). Spontaneity and feasibility of the uptake process were identified from the negative free energy (ΔG = –2.073 kJ/mol), (ΔH = 9.078 kJ/mol), and (ΔS = 0.034 kJ/mol/K). MPS could be revived well using 1:1 MeOH/H2O in up to 91% and elegantly reused for six cycles without significant loss in activity. [ABSTRACT FROM AUTHOR]

The polycrystalline ferrite samples of NixCo1−xFe2O4 (x = 0.1, 0.3, 0.5, 0.7, and 0.9) are synthesized through the well‐known sol–gel method. The X‐ray diffraction (XRD) pattern confirms the cubic single‐phase spinel structure. Rietveld refinement indicates the absence of any other impurity phases in the samples. Additionally, XRD analysis reveals variations in lattice parameters corresponding to the doping. The Debye Scherer formula has been used to calculate the crystallite size of the samples, the crystallite size of the samples existing in the nanoregime. The results from field emission scanning electron microscopy confirm the morphological structure of the prepared samples. Additionally, the energy‐dispersive X‐ray spectra confirm the elemental composition and purity of the synthesized samples, validating the appropriateness of doping in the polycrystalline samples. The Raman spectra give the information about the vibrational modes in the sample. The Fourier transform infrared rays spectrum shows that the samples have a broad range of chemical interactions. The photoluminescence spectroscopy (PL) suggests strong luminescence in the visible range. PL spectroscopy provides that PL intensity decreases with increasing excitation wavelength due to nanosize of the particle. [ABSTRACT FROM AUTHOR]

The study shows that the addition of gadolinium ions has a significant impact on the structure, morphology, and adsorption properties of Ni-Co spinel ferrite that was synthesized by the sol–gel auto-combustion method. The research also indicates that the higher the Gd content, the greater the increase in the lattice parameter, which suggests that Gd3+ ions uniformly replaced the octahedral Fe3+ ions. The morphology and chemical composition of Gd-doped Ni-Co ferrites have been studied using SEM and EDS. Gd adding to the NiCoFe matrix increases the BET surface area by 50% (from 48 to 72 m2/g) and promotes the formation of mesopores with an average radius from 3.9 to 4.9 nm. The pHPZC values of Gd-doped ferrites are in the range of 7.22–7.39, which means that the ferrite surface will acquire a positive charge at natural pH, so this will promote the adsorption of Congo red anionic dye through electrostatic interaction forces. Langmuir, Freundlich, and Dubinin-Radushkevich models were used to explain the mechanism of CR adsorption on the Ni0.5Co0.5GdxFe2-xO4 adsorbent surface. The ionic-covalent parameter has been estimated to describe the surface acid–base properties. Overall, this study highlights the potential of Gd3+ doping as a promising approach for enhancing the adsorption properties of nickel–cobalt ferrites. [ABSTRACT FROM AUTHOR]

A series of M/NiCo-Ferrite (M: Pt, Pd, Ru, and Rh) nanoparticles were successfully synthesized, through a facile sol–gel auto-combustion followed by impregnation-reduction approach, as a catalyst for hydrogen generation from hydrolysis of NaBH4. All synthesized samples were characterized by XRD, N2 adsorption–desorption method, ICP-OES, FE-SEM, and EDX analysis. Compared to the other samples, it was observed that the Rh/NiCo-Ferrite sample exhibited higher particle distribution and surface area. To evaluate the hydrogen generation rate, the hydrolysis was carried out at a temperature of 35 °C, with an aqueous solution containing 5 wt.% NaBH4 and 3 wt.% NaOH. The experimental findings indicate that the Rh/NiCo-Ferrite sample exhibited a superior rate of hydrogen generation, with an average value of 11,667 mL/min.gcat, compared to the other samples studied. Enhanced catalytic properties may be responsible for its high activity. In addition, the activation energy of hydrolysis of sodium borohydride over the Rh/NiCo-Ferrite sample was 54.5 kJ/mol which is lower than the activation energy of many Ferrite-based catalysts. Moreover, the re-usability test of the Rh/NiCo-Ferrite sample denoted a decline in the catalytic activity after 4 recycling experiments due to the alterations in morphology and the reduction in the quantity of active phase. [ABSTRACT FROM AUTHOR]

In this work, the structural properties of CoFe2-xMoxO4 (0.0 ≤ x ≤ 0.4) ferrites were investigated. Polycrystalline samples were prepared by chemical method and characterized by the X-ray diffraction and scanning electron microscopy. X-ray diffraction patterns show that all samples have a cubic spinel structure, and the lattice parameter a decreases monotonically with increase in Mo concentration. Scanning electron micrographs indicate that most of the particles are in the range of 400–850-nm size. The saturation magnetization, Ms, values of Mo-doped samples are larger than the parent compound with a maximum value of 106 emu/g for x = 0.2 sample. In general, in the absorption spectrum, a decrease in absorbance is observed with increasing wavelength. This phenomenon occurs because only photons with energy greater than the material's energy gap at the absorption edge are able to interact with the material, leading to the formation of electron pairs. It can be seen that the absorbance increases slightly with increasing Mo ratio. The thickness of the film is 500 nm. [ABSTRACT FROM AUTHOR]

In this study, an analysis of current welding technologies for new highstrength low-alloyed AHSS sheet steels is presented. Over the course of it, a series of welded joints of sheet metal with a thickness of 1.2 mm made of CR1000Y1370T-CH steel (composition: 0.23% C, 2% Si, 3% Mn, 0.015-2% Al, 1% Cr + Mo, 0.15% Ti + Nb, 0.2% Cu) by Voelstalpine (Austria) is investigated. The joints are produced using laser, spot, and argon-arc spot welding under specified conditions. High-quality weld joints are obtained through laser welding with the formation of a dispersed ferrite-bainite structure with an acceptable hardness level (up to 4000 MPa) without martensitic-type structures and zinc evaporation from the sheet coating along the entire length of the welded joint. As discovered, due to delamination and remnants of zinc coating, it is not possible to achieve a high quality of weld joints while using spot welding, as well as argon-arc spot welding. The selected welding conditions for these technologies are found to be ineffective and require further refinement. [ABSTRACT FROM AUTHOR]

In the present report, the structure–property correlation of 0.9BaZr0.2Ti0.8O3-0.1NiFe2O4 (0.9BZT-0.1NFO) composite is studied. The X-ray Diffraction, Raman spectroscopy and Field Effect Scanning Electron Microscopy (FESEM) reveal the existence of ferroelectric and magnetic phases without any impurity and interdiffusion. The dielectric, ferroelectric and conductivity mechanisms of the sample are studied in a wide range of temperature (RT-500°C) and frequency (100 Hz–1 MHz), respectively. The dielectric constant is larger than 2000 in low frequency (<1 kHz), while it decreases to 500 when the frequency is larger than 4 kHz. Both small polaron and correlated barrier hopping contribute to the conduction mechanism. The multiferroism at room temperature is confirmed by P-E and M-H loop study. The composite obeys the Law of Approach to Saturation at a higher field. The saturation magnetization found from fitting is in good agreement with the experimental value. [ABSTRACT FROM AUTHOR]

This work includes the synthesis of MWCNTs–CoNiFerrite composites in two methods, direct method and indirect method; however, in both cases, ultrasound was used as an environmentally friendly method. These composites were characterized using XRD, SEM, and TEM to verify the compositional effects of both methods, which would have effects on hydrogen storage capacity. The XRD measurements showed that, in both cases, cobalt–nickel ferrite was formed on the carbon nanotubes. Furthermore, the SEM and TEM measurements proved that the composition of the resulting materials was different in shape and size. The prepared composites were used as new materials for hydrogen storage in the solid state, using two different temperatures, 298 and 77 K, at a pressure ranging from 0 to 900 mmHg. The results showed that the H2 storage results reached 1.65 and 1.12 wt% at 77 K for both direct and indirect synthesized MWCNTs–CoNiFe2O4, respectively, which indicates the importance of the preparation method in the ability to store gases. Highlights: MWCNTs–CoNiFerrite composites were produced by direct and indirect ultrasonic methods. The composites were used for hydrogen storage at 298 and 77 K, and at a pressure ranging from 0 to 900 mmHg. The results showed that at 77 K, the storage results reached 1.65 and 1.12 wt% for both MWCNTs–CoNiFe2O4 by the direct and indirect methods, respectively. [ABSTRACT FROM AUTHOR]

This work aims to evaluate the behavior of AISI 308L stainless steel, applied in additive manufacturing by direct energy deposition (DED) with the GTA (TIG) process, to find the limits of using this material as a manufacturing technique. The AISI 308L is an austenitic steel with extensive applications across various industrial sectors, particularly in the chemical, food, and biomedical industries. Due to its resistance to ductile–brittle transition, it is widely utilized in cryogenic temperature working conditions. The welding equipment and the test specimen were instrumented for analysis of welding process parameters and evaluation of heat transfer in the material as a function of pulse frequency (0 Hz—conventional GTA, 100 Hz, 1 kHz, and 10 kHz) to determine its influence on ferrite morphology and printability in each test specimen. Under these conditions, the sample was characterized by optical and scanning electron microscopy (SEM) and backscattered electron diffraction (EBSD) to evaluate the direction of solidification by the deposited layer. The results showed that a pulse frequency of 100 Hz reduced the volumetric fraction of ferrite and exhibited the best printability. Furthermore, samples prepared using the pulse frequency showed higher printability values than samples without pulsation, and samples with 10 kHz showed an increase in the formation of acicular ferrite. [ABSTRACT FROM AUTHOR]

The microstructure of stainless steels belonging to the martensitic and martensitic–ferritic classes was examined by orientation microscopy (EBSD) after quenching. The steels comprised 15 wt % Cr, Ni, and Nb, and were distinguished by the addition of Cu or Mo as alloying elements. Using the spectra of deviation of interfacial α/γ-boundaries from orientation relationships (OR), as well as the initial austenitic grain recovery procedure according to OR, it was found that the martensitic transformation occurring in both steels is realized according to the closest to Kurdyumov–Sachs OR, or (112)γ || (113)α; [11 ]γ || [1 0]α OR. It is demonstrated that the δ-ferrite grains present in the martensitic−ferritic grade steel prior to and after quenching are in the same OR with austenite. This appears to be a consequence of the nucleation of martensitic crystals at the δ-ferrite/austenite phase interface. It is demonstrated also that the application of orientation microscopy enables the ascertainment of the grain austenitic structure of stainless steels at elevated temperatures with an acceptable degree of precision. This is realized by analyzing the structure resulting from shear transformation. [ABSTRACT FROM AUTHOR]

This study demonstrated the synthesis of Fe2MnO4 modified by citric acid, a biodegradable acid, using a simple co-precipitation method. Characterization was performed using qualitative analysis techniques such as Fourier-transformed infrared spectroscopy, scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy, X-ray diffraction, selected-area electron diffraction, N2 adsorption–desorption, and zero-point charge. The prepared nanoparticles had a rough and porous surface, and contained oxygenous (-OH, -COOH, etc.) functional groups. The specific surface area and average pore size distribution were 83 m2/g and 5.17 nm, respectively. Net zero charge on the surface of the prepared nanoparticles was observed at pH 7.5. The prepared nanoparticles were used as an adsorbent to remove methylene blue dye from water under various conditions. Using small amounts of the adsorbent (2.0 g/L), even a high concentration of MB dye (60 mg/L) could be reduced by about ~58%. Exothermic, spontaneous, feasible, and monolayer adsorption was identified based on thermodynamics and isotherm analysis. Reusability testing verified the stability of the adsorbent and found that the reused adsorbent performed well for up to three thermal cycles. Comparative analysis revealed that the modified adsorbent outperformed previously reported adsorbents and unmodified Fe2MnO4 in terms of its partition coefficient and equilibrium adsorption capacity under different experimental conditions. [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]

A series of Mg doped ZCFAO (Zn0.3−xMgxCu0.7Al0.3Fe1.7O4 (0.05 ≤ x ≤ 0.25) spinel samples were synthesized by solid state reaction method. XRD, was utilized to investigate the structure phase, microstructural characteristics, The optical properties were analyzed; Biological instruments Sp-150 potentiostate is employed to investigate the dielectric measurements in the frequency range of 10 Hz to 1 MHz at various temperatures from 300 to 650 K. Vibrating sample magnetometer VSM was employed to examine the magnetic characteristics in the applied magnetic field ranging from − 20 to 20 kG. The creation of a single-phase cubic spinel was validated by X-ray analysis. The leverage of replacing Zn by Mg leads to enhancement in the lattice parameters, reducing both of the degree of inversion, crystal distortion and compelled these samples to be normal spinel. It turned out that as the degree of inversion sank, the crystallite size declined. The values of dislocations density was found in the order of 10−5 which reveal improving and completing the crystallization of the ferrite samples. The samples have an optical energy gap in the range 3.1–3.38 eV, according to the inferred optical characteristics. The dielectric constant revealed the normal behavior of spinel ferrite it decreases with increasing frequency and enhanced with increasing temperature. It seems that the microstructure of the compound consists of both high-conductive grains and low-conductive grain boundaries, which has been confirmed by the complex impedance. Additionally, the presence of the Maxwell–Wagner relaxation process is also detected. This information can provide valuable insights into the properties and behavior of the compound. Using Nyquist plot, the sample impedance characteristics were interpreted while taking grain and grain boundary contributions into account. The magnetic properties proved that doping ZCFAO with diamagnetic cations (Mg) increases both of saturation magnetization from 16.416 up to 29.983 emu/g and the magnetocrystalline anisotropic constant from 1319.24 to 1612.804 because the two main factors that influence the magnetic properties are the distribution of cations between the octahedral and tetrahedral sites and the magnetic moment of each of its cations. Novelty of our work replacing Zn by Mg (both of them diamagnetic materials) enhance the magnetic properties. Synthesized materials may reexamine the mechanisms underlying Mg2+ induced cationic exchange in ZCFAO and have prospective uses as soft-magnetic materials. [ABSTRACT FROM AUTHOR]

Here we report the structural, magnetic, and dielectric properties of rare earths (Sm3+, Dy3+) substituted with MgFe2O4 ferrites. Structural analysis carried out using X-ray diffraction (XRD), indicates the presence of a minor secondary phase along with a prominent spinel phase. Samples of MgFe2O4 ferrite substituted with rare earths (Sm3+, Dy3+) exhibit anomalous saturation magnetization behavior. The magnitude of initial permeability of rare earth (Sm3+, Dy3+) substituted with MgFe2O4 ferrites was found to be quite stable in the low-frequency range and showed an increasing trend at higher frequencies. The composition Mg[(Sm)0.4(Dy)0.6]0.20Fe1.80O4 exhibits a low loss factor and enhanced initial permeability compared to other compositions. All substituted rare earth ions have lower dielectric constant and dielectric loss values than un-substituted rare earth ions. The dielectric constant of the magnesium ferrite does not vary significantly as the samarium-dysprosium content rises. Sm-Dy doping reduces the concentration of Fe3+ ions in the octahedral sites of composition. The reason is that Sm3+ and Dy3+ ions prefer the octahedral sites due to their large ionic radius. When (Sm3+, Dy3+) substituted with MgFe2O4 is compared to pure Mg ferrite it is found that the electrical resistivity of the substituted material increases because the tendency for Fe3+ and Fe2+ ion pairs to hop is reduced. [ABSTRACT FROM AUTHOR]

La-substituted Ni-Co ferrites Ni0.5Co0.5LaxFe2-xO4 (x = 0; 0.01; 0.025; 0.05), synthesized by sol–gel auto-combustion method, were tested as adsorbents for the Congo Red dye removal and as catalysts for hydrogen peroxide decomposition. XRD, SEM, EDS, and IR spectroscopy techniques were used for structure-morphology characterization. The presence of La ions resulted in a decrease in both the lattice parameter and crystallite size. The chemical composition was confirmed to be close to the expected stoichiometry through EDS analysis. The IR spectra revealed two absorption bands within the 400–600 cm–1 range, indicating the formation of the spinel structure and the introduction of La ions into the crystal lattice. The adsorption studies conducted on La-substituted Ni-Co ferrites revealed that the presence of La ions improved their adsorption properties for Congo Red dye removal. The maximum adsorption capacity has been observed for the sample with x(La) = 0.025. The obtained data fit well with the Langmuir model. The Dubinin-Radushkiewicz isotherm model was employed to determine the free energy of adsorption, which was found to be in the range of 22–25 kJ/mol, indicating the chemosorption of Congo Red molecules onto La-doped ferrites. The removal efficiency of Congo Red dye for the most active sample reached 98%. The samples manifested sufficient activity as Fenton-like catalysts in hydrogen peroxide decomposition. The NiCoLa-25 sample turned out to be the most active, decomposing H2O2 by 94%. Synthesized La-substituted Ni-Co ferrites could be both promising adsorbents and catalysts for wastewater treatment. [ABSTRACT FROM AUTHOR]

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Copyright of Atomic Energy Science & Technology is the property of Editorial Board of Atomic Energy Science & Technology 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.)

The AgMnFe2O4-MgO composite coatings with the Ag/(Mn+Fe) atomic ratio of 0, 0.3%, 1% and 3%, respectively were prepared by sol-gel method to improve antibacterial property and biocompatibility of titanium for orthopaedic implants. SEM observation shows rare cracks of the films due to the gelling effect of MgO and silver nanoparticles precipitation at the surface. XRD analysis reveals the decreased crystallinity of MnFe2O4 by the addition of MgO. XPS analysis indicates metallic Ag, high-valence manganese, Fe3+ and Mg2+ species in the composite film. Contact angle measurement and potentiodynamic polarization test show that the coating samples have higher contact angles and better corrosion resistance than the polished titanium. The bonding strength of the coating is relatively low tested by the pull-out method (2.6 MPa for sample with 1%Ag). Plate counting test demonstrates the silver content dependent antibacterial activity of the coating samples against E. coli, and the antibacterial rate reaches 100% at 1%Ag. MTT assay shows good compatibility with MC3T3-E1 cells for the samples with Ag ratio up to 1%. Silver, manganese ferrite and degradable MgO together determine the biological properties of the composite coatings. Highlights: The coatings are nearly crack-free due to the gelling effect of MgO. The coating samples have better corrosion resistance than polished titanium. The antibacterial rate of the samples with ≥1% Ag is 100% against E. coli. The samples with ≤1% Ag show good compatibility with MC3T3-E1 cells. [ABSTRACT FROM AUTHOR]

Polycrystalline magnesium ferrite (MgFe2O4) ceramics were prepared using as-prepared MgFe2O4 powder derived via sol-gel auto combustion method, and the influence of sintering temperature on the structural, electrical, dielectric, and magnetic properties of bulk ceramics have been examined. Ceramic microstructure with increased grain size, crystallite size, and densification is found to improve with increasing sintering temperatures (1100 to 1200 °C/4 h). Sintering conditions (temp. and time) are optimized. The influence of grain and grain boundaries (GB's) on electrical and dielectric properties is analysed over a wide frequency range of 0.1 Hz to 1 MHz. Ceramic sintered at 1200 °C/4 h exhibit low dc conductivity (σdc = 2.48 × 10−9 Ω−1cm−1) and a stable frequency independent dielectric constant ɛ´ ~ 15. DC conductivity determined from impedance Cole-Cole plot analysis is shown to be in close agreement with the dc conductivity estimated from ac conductivity analysis using Jonscher's power law. Saturation magnetisation (MS) increases, and coercivity (HC) decreases with increase in sintering temperature. In comparison to powders, the large crystallite size (117 nm) in dense ceramics is indicative of a larger domain size with (MS = 38 emu/g), and the well-connected ceramic grains lead to a low coercive field (HC = 21 Oe). Highlights: Optimized sintering temperatures enhance the microstructural development, improving grain size, crystallite size, and densification in the magnesium ferrite (MgFe2O4) ceramics. Electrical and dielectric properties show frequency-independent behavior at 1200 °C/4h sintering, promising stable conductivity and dielectric performance. Magnetic properties exhibit increased saturation magnetization and decreased coercivity with higher sintering temperatures, indicating improved magnetic behavior. Comparative analysis between loose powders and compacted ceramics reveals significant differences in crystallite size and magnetic domain characteristics. Overall, this study provides valuable insights into the fabrication and characterization of sol-gel derived magnesium ferrite (MgFe2O4) ceramics, offering potential advancements for various technological applications. [ABSTRACT FROM AUTHOR]

The current research focuses on the synthesis of nickel spinel ferrite nanoparticles doped with rare earth elements via green synthesis-assisted sol-gel auto combustion method. X-ray diffraction (XRD), field electron scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FT-IR), Raman spectra were carried to examine the development of phase, morphology, and crystal structure. Structural parameters, cation distribution, and lattice strain were determined through Rietveld analysis and Williamson-Hall (W-H) plots. The lattice constant shows an increasing trend with increase in Tb3+ ion concentration. Using the G-Fourier technique, the electron density mapping of Nickel nano-ferrites replaced with rare earth (Tb) elements was computed. Saturation magnetization and magnetic hysteresis loss was found to decrease with Tb3+ addition. The insignificant hysteresis curve with small coercivity value and retentivity seen demonstrates the soft behavior. The room temperature resistivity values increase with the addition of terbium. The observed dielectric dispersion with frequency is explained by the Maxwell–Wagner two-layer model and the electron hopping mechanism, which are responsible for conduction and polarization. The dielectric constant and dielectric loss decrease with the addition of Tb3+, which can be attributed to a reduction in the hopping rate due to the substitution of Fe3+ ions by Tb3+ ions at the octahedral sites. The dielectric behavior of the NiTb0.1Fe1.9O4 composition exhibits a maximum dielectric constant value with a minimal loss tangent. The Cole-Cole plot highlights the role of grains and grain boundaries in the bulk material. Through impedance studies, the resistance and capacitance of both the grains and grain boundaries have been determined. The increased resistivity and reduced dielectric loss attained in Tb doped ferrite is promising as it is desirable for high frequency applications. Highlights: Synthesis of Tb doped nickel spinel ferrite nanoparticles via green synthesis-assisted sol-gel auto combustion method. The manifestation of paramagnetic behavior of Tb3+ ions at room temperature was corroborated from the magnetic study. The detailed dielectric dispersion is explained by the Maxwell–Wagner two-layer model and the electron hopping mechanism. The dielectric dispersion is responsible for conduction and polarization. The Cole-Cole plot highlights the role of grains and grain boundaries. The increased resistivity and reduced dielectric loss makes the material desirable for high frequency applications. [ABSTRACT FROM AUTHOR]

With advancements in the field of electrical engineering, various low-power portable electronic devices have been commercialized. To eliminate and unify different types of cables, inductive wireless power transfer (WPT) technology, which uses magnetic fields to transfer energy, is being applied in numerous applications. Low-power devices typically have small coils and loads, leading to low power transfer efficiency even over short distances. Magnetic materials such as ferrites are used to improve power transfer efficiency (PTE). It is well known that high-permeability ferrites with low magnetic reluctance are ideal for achieving strong magnetic coupling. However, continuous increases in permeability raise the cost and weight of the ferrite, making it necessary to select ferrites with appropriate permeability from a mass-production perspective. This paper models and analyzes the changes in mutual inductance and power transfer efficiency with varying ferrite permeabilities using magnetic circuits, providing guidelines for the selection of suitable ferrites considering efficiency improvements. The proposed method is validated through 3D electromagnetic simulations and experiments, showing a power transfer efficiency difference of up to 0.6% between the experimental and calculated results. [ABSTRACT FROM AUTHOR]

Using scanning tunneling microscopy, it is shown that a lath structure is formed in the heat-affected zone of the low-carbon, low-alloy 09G2S steel after electric arc surfacing. Analysis of the results of scanning tunneling microscopy revealed a number of subtle morphological features of the lath structure, which makes it possible to explain the mechanism of its formation and identify it as lower bainite. The lower bainite structure in the heat-affected zone of the base metal of the 09G2S steel is favourable for increasing the impact strength of the coating – base metal composition, which was established earlier in our work. [ABSTRACT FROM AUTHOR]

To increase the effectiveness of various electrochemical energy conversion and storage systems, electroactive and affordable electrocatalysts must be developed. Herein, the developed ultrasonic approach in the design and synthesis of the Fe-based spinel oxide (Fe3O4, CdFe2O4, CrFe2O4, and Cd0.2Cr0.8Fe2O4) nano-boxes, whose electrochemical performance was studied, is reported. The X-ray diffraction patterns proved the presence of the complete solitary-phase nano-spinel oxides. The Fourier-transform infrared spectra also supported the developed oxide structures. The thermogravimetric analysis showed a notable decline in the sample's weights, with the most significant weight loss observed at approximately 35.46%. The cyclic voltammetry and the Tafel measurements were applied to investigate the electrochemical merits of the synthesized nanoparticles on a titanium supported electrode for different electrocatalytic applications. The results from cyclic voltammetry revealed that the substitution of the A site of the Fe atom with Cr or Cd had a detrimental impact on the current density value, and the ferrite with only chromium substitution exhibited the minimal current density at 0.7 V. The electrocatalytic activity estimated by Tafel curves towards an oxygen evolution reaction, ethanol and methanol oxidation reactions showed that the ternary ferrite with cadmium and chromium substitution (Cd0.8Cr0.2Fe2O4) had the highest current density of 0.224 mA/cm2 at 850 mV towards an oxygen evolution reaction and was the most active towards a methanol oxidation reaction. [ABSTRACT FROM AUTHOR]

In biosensors, the development of low-cost, high-sensitivity catalysts for glucose and hydrogen peroxide (H2O2) detection has broad research prospects. Herein, porous CoFe2O4 nanotubes (p-CFONTs) were synthesized by an electrospinning technique and subsequent calcination. As a catalyst in biosensors, p-CFONTs exhibit high catalytic activity towards glucose and H2O2. In detail, p-CFONT-modified nickel foam exhibits a high sensitivity to glucose of 1170 μA cm−2 mmol L−1 and a low detection limit of 9.7 μmol L−1 in a wide linear range from 20 μmol L−1 to 4.0 mmol L−1. In the case of H2O2 sensors, p-CFONT-modified electrodes show a high sensitivity of 478 μA cm−2 mmol L−1 and a low detection limit of 230 μmol L−1 in a wide linear response of 0.5 mmol L−1 to 22.5 mmol L−1. The good sensing performance for glucose and H2O2 of p-CFONT-modified electrodes is attributable to the porous and hollow structure of p-CFONTs. This work has guiding significance for the design of multifunctional electrodes in nonenzymatic glucose and H2O2 sensors. [ABSTRACT FROM AUTHOR]

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