Magnetic Characteristics Research Articles

Structural properties of glucan from Russula griseocarnosa and its immunomodulatory activities mediated via T cell differentiation

The polysaccharide, RGP2, was isolated from Russula griseocarnosa and its immunostimulatory effects were confirmed in cyclophosphamide (CTX)-induced immunosuppressed mice. Following purification via chromatography, structural analysis revealed that RGP2 had a molecular weight of 11.82 kDa and consisted of glucose (Glc), galactose (Gal), mannose, glucuronic acid and glucosamine. Bond structure analysis and nuclear magnetic resonance characterization confirmed that the main chain of RGP2 was formed by →6)-β-D-Glcp-(1→, →3)-β-D-Glcp-(1→ and →6)-α-D-Galp-(1→, which was substituted at O-3 of →6)-β-D-Glcp-(1→ by β-D-Glcp-(1→. RGP2 was found to ameliorate pathological damage in the spleen and enhance immune cell activity in immunosuppressed mice. Based on combined multiomics analysis, RGP2 altered the abundance of immune-related microbiota (such as Lactobacillus, Faecalibacterium, and Bacteroides) in the gut and metabolites (uridine, leucine, and tryptophan) in the serum. Compared with immunosuppressed mice, RGP2 also restored the function of antigen-presenting cells, promoted the polarization of macrophages into the M1 phenotype, positively affected the differentiation of helper T cells, and inhibited regulatory T cell differentiation through the protein kinase B (AKT)/mechanistic target of rapamycin (mTOR) pathway, ultimately exerting an immune boosting function. Overall, our findings highlight therapeutic strategies to alleviate CTX-induced immunosuppression in a clinical setting.

Influence of bismuth and cobalt doping on structural, dielectric, and magnetic properties of M-type calcium hexagonal ferrites

M-type hexagonal ferrites have been getting considerable attention owing to their promising application in electronic fields. Though, the growth of nanosized M-type hexagonal ferrites is still a big challenge. Herein the fabrication of M-type hexaferrite with nominal composition Ca1-xBixFe12-xCoxO19 (x=0.00, 0.05, 0.10, 0.15, 0.20) with high quality is reported by the sol-gel auto combustion route. The objective of the study is to improve the structural, spectral, dielectric, and magnetic characteristics of M-type hexagonal ferrite which was achieved through the variation of concentration of Cobalt and Bismuth. X-ray diffraction (XRD) patterns confirmed the single-phase M-type hexagonal structure. The crystallite size of all samples was found to be in the range of 42–49 nm. Other parameters such as lattice parameters a & c, unit cell volume, crystallite size, X-ray density, Bulk density, and porosity were also calculated. The doping contents were found to decrease the bulk and X-ray densities while increasing the porosity. Fourier-transform infrared (FTIR) spectra showed the formation of metal-oxygen stretching vibrations that confirmed the formation of hexagonal ferrites. The scanning electron microscopy (SEM) images revealed a regular platelet hexagonal structure and homogeneously distributed grains were examined. The dielectric constant was high at low frequency and then decreased with increasing frequency, while the dielectric loss was decreased appreciably with doping. The saturation magnetization ranged from 15.51 to 38.27 emu/g, coercivity increased from 207.93 to 1359.69 Oe, and the squareness ratio was found to be in the range of 0.19–0.78. The dielectric and magnetic properties of Ca1-xBixFe12-xCoxO19 (x=0.00, 0.05, 0.10, 0.15, 0.20) with the variation of Co and Bi revealed that these materials are good candidates for modern devices.

Curie temperature and magnetic permeability regulation of Cr–Mg co-doped NiCuZn ferrite for tumor hyperthermia

The controllable Curie temperature and high magnetic permeability of NiCuZn ferrites make them promising candidates for magnetic thermal medium. However, the temperature control of existing NiCuZn ferrite materials is not accurate enough to achieve the low Curie temperature required for tumor hyperthermia. In order to further achieve the desired Curie temperature and facilitate the advancement of temperature control materials for tumor hyperthermia, Cr–Mg co-doped NiCuZn ferrite was studied. The study investigated the influence of varying concentrations of Cr3+ on the crystal structure and magnetic properties of Mg–NiCuZn ferrites. The results of structural characterization demonstrate that Cr–Mg co-doped NiCuZn ferrites exhibit high density and uniform distribution of elements. The introduction of Cr3+ leads to a reduction in lattice parameters and a preference for octahedral B-sites. The hysteresis loop results show that the saturation magnetization first increases and then decreases with the increase of Cr3+ concentration. Ni0.09Mg0.20Cu0.14Zn0.60Fe1.89Cr0.050O3.94 ferrite at 0.30 wt% of Bi2O3 exhibits optimal magnetic characteristics, including a saturation magnetization of ∼36.7 emu/g, low coercivity of ∼0.07 kA/m, high permeability of ∼982.43 @1 MHz, and an appropriate Curie temperature of 45.59 °C. Such permeability and Curie temperature can be used in the body cavity perfusion hyperthermia and deep thermal therapy.

Observation of skyrmion-induced topological Hall effects in Mn3.5Au0.5N films

The Mn4-xAuxN films were grown on MgO(001) substrates by plasma assisted molecular beam epitaxy. The magnetic characteristics and spin transport properties are systematically studied. A sign reversal of anomalous Hall coefficient is observed at 160 K in Mn3.5Au0.5N. This phenomenon can be attributed to the competition between electron-like and hole-like anomalous Hall effects (AHEs). The mutual eliminating of electron-like and hole-like AHEs gives rise to zero resistivity of 160 K at high field. A butterfly-like curve with two humps is observed at 160 K, which can be ascribed to the skyrmion-induced topological Hall effects (THEs). It is thus confirmed that the transverse resistivity in Mn3.5Au0.5N comprises of three components: electron-like AHEs, hole-like AHEs, and skyrmion-induced THEs. An effective method was employed to analyze THEs in the material systems that contain both electrons and holes. The THEs in Mn3.5Au0.5N can be observed after electron-like AHEs are subtracted down from transverse resistivity.

Magnetic and optical properties of ZnO nanoparticles and nanorods synthesized by green chemistry

ZnO nanostructures have attracted considerable attention because of their physicochemical properties and applications as antibacterial agents, photocatalytic reactions for pollutant removal, and electronics. Hence, efficient production and knowledge of their properties under different synthesis conditions are essential. Biosynthesis has emerged as an excellent growth-directing method for synthesizing nanomaterials, representing a soft and cleaner alternative for their production. In this study, we synthesized different ZnO nanostructures using a soft chemistry method at different growth temperatures, from 200 to 800 °C every 200 °C. The crystalline structure was estudied by x-ray Diffraction (XRD) and High-Resolution Transmission Electron Microscopy (HRTEM). The shape and size were studied by Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM), which revealed a ZnO hexagonal phase with two shapes: nanoparticles (NPs) with irregular shapes and nanorods of different sizes. The optical properties were studied by Raman and UV-visible spectroscopy, and optical absorption measurements showed bandgap tuning of the produced nanostructures. Finally, the magnetic characteristics of the samples demonstrated magnetic anisotropy due to the preference for crystalline formation and the size of the nanoparticles. The magnetic interaction between the two types of NPs increased the diamagnetism associated with the nanorods.

The effect of thickness of the hot-rolled sheet on the magnetic properties of non-oriented electrical steel

Non-oriented (NO) electrical steel sheets with a thin thickness are drawing interest as potential materials for electric vehicle drive motor cores due to their ability to reduce high-frequency core loss. To produce electrical steel sheets with a thickness of 0.25 mm or less, it is beneficial to minimize the thickness of the hot-rolled sheets. However, it is well known that it is difficult to achieve hot-rolled coils with a thickness of 1.4 mm or less with a conventional hot rolling process. Therefore, the thin slab casting and rolling (TSCR) process is now used to produce thin hot-rolled coils that cannot be produced by conventional methods.In this study, we investigated the effects of hot-rolled sheet thickness produced by the TSCR process and cold-rolling reduction ratio on the crystallographic texture, microstructure, and magnetic characteristics of 3% Si NO steel. The results showed that the textures of the hot-rolled sheet and the annealed hot-rolled sheet are virtually unaffected by the hot-rolling reduction ratio. However, the cold-rolling reduction ratio substantially affects many aspects of NO electrical steels. The recrystallized grain size after the final annealing process decreases as the cold reduction ratio increases, while the magnetic flux density decreases with increasing cold reduction ratio, especially for reductions exceeding 82.8 %.In conclusion, the thickness of hot-rolled steel sheets manufactured by the TSCR process has little effect on the microstructure and texture of hot-rolled sheet. Therefore, reducing the cold rolling reduction ratio, which can be achieved by using thin hot-rolled sheets manufactured by the TSCR process, is a promising method for enhancing the magnetic characteristics of thin-gauge NO electrical steel sheets.

Geometrically frustrated Gd2Ti2O7 oxide: A comprehensive exploration of structural, magnetic, and magnetocaloric properties for cryogenic magnetic cooling applications

The magnetocaloric effect (MCE) has been extensively studied in various magnetic solids, aiming to both facilitate practical applications in magnetic cooling and deepen our understanding these materials’ intrinsic properties. This study presents a systematic investigation of Gd2Ti2O7 oxide, characterized by a geometrically frustrated magnetic structure, focusing on its structural and magnetic characteristics through experimental analysis and theoretical calculations. Emphasis is placed on its magnetic phase transition (MPT) and magnetocaloric properties, scrutinizing temperatures as low as 0.4 K and magnetic fields up to 16 T. The results reveal that Gd2Ti2O7 oxide possesses a crystalline cubic pyrochlore-type structure with an antiferromagnetic (AFM) semiconductor ground state. The material undergoes a first-order MPT in low field and low-temperature regimes, transitioning to a second-order MPT above 2 K up to 16 T. Evaluation of magnetocaloric parameters, including maximum magnetic entropy change, temperature-averaged entropy change, relative cooling power, and refrigerant capacity, indicates moderate values under low magnetic field changes, while significantly large values are achievable under high magnetic field changes. This finding suggests that potential cryogenic magnetocaloric materials (MCMs) with optimal performance should exhibit low MPT temperatures induced by magnetic frustration and possess a ground state with a sufficiently large magnetic moment induced by low magnetic fields, thus avoiding excessively strong AFM coupling. This study lays the groundwork for future cryogenic MCM design and provides valuable insights into the intrinsic properties of geometrically frustrated magnetic materials.

Magnetically propagating Hund’s exciton in van der Waals antiferromagnet NiPS3

Magnetic van der Waals (vdW) materials have opened new frontiers for realizing novel many-body phenomena. Recently NiPS3 has received intense interest since it hosts an excitonic quasiparticle whose properties appear to be intimately linked to the magnetic state of the lattice. Despite extensive studies, the electronic character, mobility, and magnetic interactions of the exciton remain unresolved. Here we address these issues by measuring NiPS3 with ultra-high energy resolution resonant inelastic x-ray scattering (RIXS). We find that Hund’s exchange interactions are primarily responsible for the energy of formation of the exciton. Measuring the dispersion of the Hund’s exciton reveals that it propagates in a way that is analogous to a double-magnon. We trace this unique behavior to fundamental similarities between the NiPS3 exciton hopping and spin exchange processes, underlining the unique magnetic characteristics of this novel quasiparticle.

Magnetic characterization of HPT-deformed Fe–Si soft magnetic alloys before and after heat treatment and internal stress calculations

Fe, Fe-3wt%Si, and Fe-6.5 wt%Si alloys were subjected to high-pressure torsion (HPT) to achieve a nanostructure (<100 nm grain size). HPT processing was done at 77 and 293 K and heat treatments were performed on the deformed samples to reduce internal stresses that are known to deteriorate soft magnetic properties by impeding the movement of domain walls. X-ray line profile analysis (XLPA) was used to find out the crystallite/subgrain/domain size and the dislocation density in the deformed samples. The coercivity Hc was characterized on ring-shaped samples using a hysteresisgraph. Internal stresses in the deformed and heat-treated samples were determined using magnetic data and the dislocation density data and a comparison is made between the two approaches. HPT deformation increases the coercivity of the samples while heat treatment after deformation reduces the coercivity to a certain extent in Fe samples but has mixed results in Fe–Si alloys. In comparison with Herzer's theory, zero-frequency Hc was plotted against crystallite (or subgrain) size and it was found that coercivity follows a D1.5 relation, where D is crystallite size.

Stimuli-Induced Controls of Magnetic and Photophysical Properties Using Liquescent Open-Shell Ionic Molecular Systems.

This study explores the remarkable properties of liquescent open-shell ionic molecular systems, emphasizing the magnetic and photophysical characteristics arising from their associated structures in the condensed state under various conditions. Well-investigated open-shell molecules, namely, phenothiazine, dihydrophenazine, and tetrathiafulvalene radical cations, and bis(malononitriledithiolato)nickel(III) anionic complexes were examined, and the concept of liquescent open-shell ionic molecular systems was devised. Transformations in their associated structures are induced by external stimuli, resulting in significant variations in their physical properties. These experimental findings open new avenues for exploring and applying stimuli-responsive molecule-based materials.

The influence of thioether-substituted ligands in dicopper(II) complexes: Enhancing oxidation and biological activities

This paper describes the synthesis, structural analysis, as well as the magnetic and spectroscopic characterizations of three new dicopper(II) complexes with dinucleating phenol-based ligands containing different thioether donor substituents: aromatic (1), aliphatic (2) or thiophene (3). Temperature-dependent magnetometry reveals the presence of antiferromagnetic coupling for 1 and 3 (J = −2.27 cm−1 and -5.01 cm−1, respectively, H = -2JS1S2) and ferromagnetic coupling for 2 (J = 5.72 cm−1). Broken symmetry DFT calculations attribute this behavior to a major contribution from the dz2 orbitals for 1 and 3, and from the dx2-y2 orbitals for 2, along with the p orbitals of the oxygens. The bioinspired catalytic activities of these complexes related to catechol oxidase were studied using 3,5-di-tert-butylcatechol as substrate. The order of catalytic rates for the substrate oxidation follows the trend 1 > 2 > 3 with kcat of (90.79 ± 2.90) × 10−3 for 1, (64.21 ± 0.99) × 10−3 for 2 and (14.20 ± 0.32) × 10−3 s−1 for 3. The complexes also cleave DNA through an oxidative mechanism with minor-groove preference, as indicated by experimental and molecular docking assays. Antimicrobial potential of these highly active complexes has shown that 3 inhibits both Staphylococcus aureus bacterium and Epidermophyton floccosum fungus. Notably, the complexes were found to be nontoxic to normal cells but exhibited cytotoxicity against epidermoid carcinoma cells, surpassing the activity of the metallodrug cisplatin. This research shows the multifaceted properties of these complexes, making them promising candidates for various applications in catalysis, nucleic acids research, and antimicrobial activities.

Numerical simulation of the electromagnetic field in the secondary cooling zone of arc-shaped slabs

The magnetic field characteristics due to electromagnetic stirring in the secondary cooling zone of an extra-thick slab during continuous casting are numerically determined using Maxwell's equations, with particular emphasis on the distribution of magnetic induction intensity and electromagnetic force, as well as the influence of process parameters on the magnetic field. The orientation of the electromagnetic force is the same when the electromagnetic stirrers at the 30° and 60° posistions of the arc-shaped slab are powered in the same direction; otherwise, the orientation is opposite. The magnetic induction at the centre of the section of the stirrer's central axis at the 30° positio, as well as the current, frequency, and fitting formulae, are as follows: B = {0.075I(1/A)-0.3} mT and B = {-1.75f(1/Hz)+22} mT. The electromagnetic force and current fitting formula at the central point of the B-B section is F = {0.03168I2(1/A2)-03.762I(1/A)+326.7} N/m3, and the fitting formula of electromagnetic force and frequency at the centre point is divided into two segments. The first takes the form of a parabola: = {-21((f-4.3)-(1/Hz)2)+970} N/m3, and the second segment is negative linear: F = {-1.65f(1/Hz)+51.5} N/m3.

Facile synthesis of co-axially electrospun Co-C nanofibers and their ferromagnetic behavior

We describe a simple co-axial electrospinning approach followed by a carbonisation process to create cobalt-carbon (Co-C) nanofibers that are then thoroughly analysed using various techniques. X-ray diffraction measurements showed the creation of pure crystalline cobalt with face-centered cubic (fcc) structure, and average crystallite size was determined using the Debye–Scherrer formula. The average crystallite size has been calculated to be in the range of 10 − 15 nm. According to the Raman investigation, all Co-C nanofibers have an amorphous carbon structure with little graphitic behaviour. Field emission scanning electron microscopy was used to determine the shape and average diameter of electrospun nanofibers. The field-dependent magnetic characterisation demonstrated a satisfactory ferromagnetic behaviour with maximum saturation magnetisation values of 10, 10.2, and 11.2 emu/g for Co12.5-C sample at 300, 100, and 5 K, respectively. Compared to bulk cobalt, the produced Co-C nanofibers have a high coercivity value. With average crystallite size, the coercivity varies. Again, magnetisation versus temperature measurements have supported the existence of ferromagnetism because there is no evidence of blocking temperature or any transitional behaviour below 300 K. As a result, applications for microwave absorption, catalysis, and several magnetic recording devices can benefit from the coupling of ferromagnetic properties with carbon nanofiber materials.

Performance Study of High-Speed Permanent Magnet Synchronous Motor with Amorphous Alloy Considering Temperature Effect.

Because the magnetic properties of an amorphous alloy (AA) obviously change with the change of temperature, a finite element simulation method for a motor, considering the effect of temperature, is proposed in this paper. In the early design stage of the high-speed permanent magnet synchronous motor (PMSM), the simulation of motor performance is mainly based on the magnetic performance test data at room temperature provided by the material's manufacturer. However, the influence of the temperature rise during the actual operation of the motor will lead to large errors between the simulation results and the measured results. Therefore, it is of great practical significance to measure the magnetic properties of the AA at different temperatures and use them for simulation purposes. In this paper, the magnetization characteristics and iron loss characteristics of the AA and silicon steel (ST100) used for comparison are measured at different temperatures, and the iron loss separation of the two materials at different temperatures is completed, and the hysteresis loss coefficient and eddy current loss coefficient at different temperatures are obtained. On this basis, the performance simulation of a motor model is carried out. The more accurate simulation method proposed in this paper can provide a reference for the design of AA motors in industry.

Potential Biomedical Applications of Terbium-Based Nanoparticles (TbNPs): A Review on Recent Advancement.

The scientific world is increasingly focusing on rare earth metal oxide nanomaterials due to their consequential biological prospects, navigated by breakthroughs in biomedical applications. Terbium belongs to rare earth elements (lanthanide series) and possesses remarkably strong luminescence at lower energy emission and signal transduction properties, ushering in wide applications for diagnostic measurements (i.e., bioimaging, biosensors, fluorescence imaging, etc.) in the biomedical sectors. In addition, the theranostic applications of terbium-based nanoparticles further permit the targeted delivery of drugs to the specific site of the disease. Furthermore, the antimicrobial properties of terbium nanoparticles induced via reactive oxygen species (ROS) cause oxidative damage to the cell membrane and nuclei of living organisms, ion release, and surface charge interaction, thus further creating or exhibiting excellent antioxidant characteristics. Moreover, the recent applications of terbium nanoparticles in tissue engineering, wound healing, anticancer activity, etc., due to angiogenesis, cell proliferation, promotion of growth factors, biocompatibility, cytotoxicity mitigation, and anti-inflammatory potentials, make this nanoparticle anticipate a future epoch of nanomaterials. Terbium nanoparticles stand as a game changer in the realm of biomedical research, proffering a wide array of possibilities, from revolutionary imaging techniques to advanced drug delivery systems. Their unique properties, including luminescence, magnetic characteristics, and biocompatibility, have redefined the boundaries of what can be achieved in biomedicine. This review primarily delves into various mechanisms involved in biomedical applications via terbium-based nanoparticles due to their physicochemical characteristics. This review article further explains the potential biomedical applications of terbium nanoparticles with in-depth significant mechanisms from the individual literature. This review additionally stands as the first instance to furnish a "single-platted" comprehensive acquaintance of terbium nanoparticles in shaping the future of healthcare as well as potential limitations and overcoming strategies that require exploration before being trialed in clinical settings.

Physical properties of CoX'ZrGa (X' = V, Cr) quaternary-Heuslers: A first-principles investigation

The prime intention of this investigation is to examine the magnetic, thermoelectric, mechanical, electrical, structural, and thermodynamic characteristics of CoVZrGa and CoCrZrGa quaternary Heusler compounds. The FP-LAPW approach and Boltzmann transport equation are employed, utilizing classical Boltzmann approximations in the background of density functional theory (DFT) as implemented within WIEN2K software. The structure optimization employed the PBE approximations and the Murnaghan-Birch equation of state, leading to a stable phase for CoVZrGa and CoCrZrGa. The observed negative formation energy implies that the synthesis of CoVZrGa and CoCrZrGa is feasible. The Heusler compounds under investigation, which exhibit a narrow band gap in one spin direction and metallic behavior in the other, are classified as half-metallic (HM) based on the analysis of their electronic properties. The results for thermodynamic and elastic parameters confirm both alloys' thermal and mechanical stability. Critical analysis of thermoelectric properties demonstrates these compounds ssare feasible materials for thermoelectrical applications.

Fabrication of cisplatin-loaded core–shell Fe3O4@UiO-66-NH2 magnetic nanocomposite for potential drug delivery

In this study, we developed a biocompatible core–shell magnetic Fe3O4@UiO-66-NH2@CisPt nanocomposite loaded with cisplatin as a therapeutic agent for drug delivery and cancer treatment. The nanocomposite was synthesized using a step-by-step method resulting in the formation of two phases within the core–shell structure. Advanced analytical techniques, such as XRD, HR TEM, TEM, FTIR, and VSM, were used to thoroughly analyze the structural properties, morphology, magnetic characteristics, and atomic structure of the core–shell nanocomposite. Fe3O4@UiO-66-NH2@CisPt nanocomposite exhibits superparamagnetic behavior, which is advantageous for controlled drug delivery and release by applying an external magnetic field. This study presents a significant contribution to the development of effective drug delivery systems for cancer treatment.

Magnetism and electronic properties of ConMoP (n = 1 ~ 5) cluster: a DFT study.

Hydrogen has emerged as a promising clean energy carrier, underscoring the imperative need to comprehend its adsorption mechanisms. This study delves into the magnetic and electronic properties of Co-Mo-P clusters, aiming to unveil their catalytic potential in hydrogen production. Employing density functional theory (DFT), we optimized cluster configurations and scrutinized their magnetic behaviors. Our investigation unveiled 16 stable configurations of the ConMoP (n = 1 ~ 5) cluster, predominantly in steric forms. The magnetic attributes were primarily ascribed to the d orbitals of Co metal atoms, with Co3MoP exhibiting exceptional magnetic characteristics. Analysis of density of state diagrams revealed the prevalence of spin-up α-electrons in d orbitals, while spin-down β-electrons attenuated overall magnetic properties. Localized orbital (LOL) analysis highlighted stable covalent bonds within the clusters, affirming their catalytic potential. Orbital delocalization index (ODI) analysis revealed diverse spatial distribution ranges for orbitals across different configurations, suggesting a progressive attenuation of off-domain properties with increasing cluster size. Furthermore, infrared spectroscopy unveiled distinct vibrational peaks in various configurations, indicative of unique infrared activities. These findings contribute to a nuanced theoretical understanding of Co-Mo-P clusters and pave the path for future research aimed at augmenting their catalytic efficiency in hydrogen production. This study underscores the viability of Co-Mo-P clusters as alternatives to conventional Pt catalysts, offering insights into the design of novel materials for sustainable energy applications. Further research is warranted to explore the behavior of the Co-Mo-P system under diverse reaction conditions, fostering advancements in materials and energy science. In this study, we harnessed the ConMoP (n = 1 ~ 5) cluster as a simulation platform for probing the local structure of the material. Our aim was to scrutinize the magnetism, electronic characteristics influenced by the varying metal atoms within these clusters. A systematic exploration involved incrementing the number of metal atoms and expanding the cluster size to elucidate the corresponding property variations. Density functional theory (DFT) calculations were pivotal to our methodology, employing the B3LYP hybrid functional implemented in the Gaussian16 software package. The ConMoP (n = 1 ~ 5) cluster underwent optimization calculations and vibrational analysis at the def2-tzvp quantization level, yielding optimized configurations with diverse spin multiplet degrees. To comprehensively characterize and visually represent the stability, electronic features, and catalytic attributes of these configurations, we employed a suite of computational tools. Specifically, quantum chemistry software GaussView and wave function analysis software Multiwfn played integral roles. Through the integrated use of these computational tools, we acquired valuable insights into the magnetism, electronic characteristics of the ConMoP (n = 1 ~ 5) cluster, shedding light on their dependency on distinct metal atoms.

Aluminium and praseodymium doped M-type hexaferrites for electric vehicle applications

The booming demand for electric vehicles, driven by the pursuit of enhanced efficiency, faces significant hurdles attributed to the costly integration of rare earth magnets like NdFeB. M-type strontium ferrite emerges as a promising alternative owing to its economic viability and exceptional magnetic characteristics, rendering it suitable for electric vehicle motor applications. This research focuses on the synthesis and characterization of SrFe12O19 and Sr1-xPrxFe10Al2O19 (where x = 0.00 to 0.20) hexaferrites, with praseodymium (Pr) substitution. Magnetic particles were synthesized utilizing the sol-gel auto-combustion technique, employing a calcination temperature of 1100 °C for a duration of 4 h. Structural and magnetic studies of aluminium-praseodymium (Al–Pr) doped samples are performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibrating-sample magnetometry (VSM). The structural analysis reveals a decrease in both particle size from 42 nm to 31.76 nm and lattice parameter with increasing doping concentration. Magnetic analysis yields crucial insights: Al3+ doping induces a substantial rise in coercivity from 5500 Oe to 10,500 Oe which is quite comparable to NdFeB, while Pr doping shows a subtle impact, enhancing remanence from 17 emu/g to 23.05 emu/g. These findings underscore the potential for optimizing magnetic properties through meticulous control of dopant concentrations in M-type hexaferrites, thereby positioning them as promising substitutes for rare earth magnets.

Enhanced structural, magnetodielectric, and multiferroic response in Fe and Co Co-doped Barium strontium titanate ceramics

In this paper, the ambient temperature multiferroic effect resulting from the incorporation of transition metal ions (Fe3+ and Co2+) in lead-free BST [ Ba0.7Sr0.3(Fex/2Cox/2)Ti1−xO3;x=0,0.01,0.03,0.05,0.07 ] ceramics synthesized via the solid-state reaction (SSR) procedure has been thoroughly analyzed. The investigation consistently scrutinized the effects of augmenting transition metal co-doping on the structural, ferroelectric, dielectric, magnetic, and magnetodielectric characteristics. The x-ray diffraction (XRD) patterns for all ceramic compositions demonstrated the formation of a monophasic (P4mm) crystalline structure. The Raman analysis evidenced the presence of various modes, which are associated with the occurrence of the single-phase and provide strong corroboration for the x-ray diffraction observations. Scanning electron micrographs reveals that the inclusion of transition metal ions results in the diminution of grain size. The frequency-dependent dielectric characteristics were represented over the frequency range of 1 kHz to 1 MHz. The P-E hysteresis curves demonstrate a consistent reduction in the values of Ps and Pr, whereas, the M-H curve reveals the enhancement in magnetic properties with increased doping. The magnetodielectric analysis confirmed the interplay between the ferroelectric and ferromagnetic ordering. The BST-1CF sample exhibited the highest MC % value of 5.30% along with the magnetoelectric coupling coefficient ‘γ’ of −6.01×10−1(memu/g)−2, making it a favorable entrant for the advancement of innovative non-volatile multiferroic memory gadgets.