Magnetic Characteristics Research Articles

Impact of Gd doping on structural and magnetic characteristics of SrFeO3 perovskite nanomaterial

The SrFeO3nanoparticles doped with 5% and 10% Gd were synthesized using the solution combustion method. The phase formation of the synthesized nanoparticles was confirmed by powder x-ray diffraction analysis. Field emission scanning electron microscope and HRTEM were employed to examine the morphology of the samples, revealing well-ordered, agglomerated nanoparticles. Energy dispersive x-ray spectroscopy analysis was conducted on all samples, confirming the presence of the desired elements. X-ray photoelectron spectroscopy confirmed the presence of mixed oxidation states of Fe3+and Fe4+. Magnetization studies, performed using a SQUID magnetometer, showed ferromagnetic behaviour in all samples, with a significant increase in magnetic moment observed with higher Gd doping. The enhanced magnetic moments and reduced coercivity in Gd-doped SrFeO3suggest that these materials could be suitable for spintronic applications.

Leveraging anchoring ligands for efficient one-pot solvothermal synthesis of PDMS functionalized iron oxide polymer nanocomposites (PNC’s)

Producing substantial quantities of high purity, narrow size distribution, magnetic polymer nanocomposites (PNC’s) has been a challenge for the nanoparticle synthesis community. In this study, we introduce a novel one-pot solvothermal synthesis technique to produce a type of PNC known as a ferrofluid. By employing a polymer (polydimethylsiloxane (PDMS)) modified with anchoring ligands as the surfactant, we eliminate the need for a post-synthesis ligand exchange, resulting in high yield and purity of the final product. This approach offers greater flexibility in polymer selection and simplifies the synthetic process. Electron microscopy, magnetic characterization, infrared spectroscopy, and thermal analysis were employed to investigate particle size, crystallinity, magnetic behavior, and surface environment. Our findings suggest that this new synthetic technique could significantly advance the development of magnetic nanoparticle-based theranostics.

Structural, electrical and magnetic studies on Zn doped MnFe2O4 nanoparticles with via Sol-Gel approach

A manganese ferrite (MnFe2O4) nanoparticle is prepared through sol-gel method. The various concentration of Zn (x = 0.0, 0.1, 0.3, 0.5, 0.7, 0.9) was added to the initial solutions. Through X-Ray diffraction examinations results confirmed the cubic spinel structure of Mn1-xZnxFe2O4 and have larger crystallite size. The functional analysis is obtained through Fourier transform infrared spectroscopy (FTIR) analysis and it is indicated that Fe-O, Mn-O, and Zn-O vibrational bands. The optical analysis carried out through UV–visible spectrometer. The surface features with morphology and its content of elements in the samples were found through scanning electron microscope (SEM) with energy dispersive (EDAX) analysis. The energy analysis carried out through Xray Photo electro absorption (XPS) analysis. The detailed magnetic characteristics of the resulting samples such as cohersivity (Hc), magnetization (Ms), retentivity (Hr), squareness ratio (SQR) and anisotripic constant (Ki) were found through vibrating sample magnetometer (VSM), shows good magnetic property, multi grain wall and the strong dependents of Zn . The dielectric related parameters like dielectric constant for real and imaginary components, loss tangent with AC conductivity with respect to applied frequency are enhanced dielectric constant and at the same time it reduces the dielectric loss tangent discussed through LCR measurement. The electrochemical behaviour of the samples was tested through cyclic voltameter setup. Finally, concluded with their merits and demerits.

Analytic Hierarchy Process (AHP)-Based Evaluation of Extremely-Low-Frequency Magnetic Field Contribution Rates

The extremely-low-frequency (ELF) magnetic fields of submarines serve as key characteristics for target detection, with their formation mechanisms being complex and diverse. Effectively manipulating a submarine to reduce its magnetic signature is crucial for enhancing its magnetic stealth capabilities. However, current research on the impact of various causative factors is insufficient. This study proposes a contribution rate assessment method based on the Analytic Hierarchy Process (AHP) model, aiming to provide a theoretical basis for effective manipulation. Initially, a thorough analysis of the threat causes of a submarine’s ELF magnetic fields is conducted, and a corresponding hierarchical threat structure model is established. Subsequently, magnetic field signal characteristics generated by different causes are obtained through simulation, and threat matrices and characteristic matrices are constructed. Finally, the contribution rates of different causative magnetic fields to the total magnetic field are calculated, and the simulation results validate the effectiveness of the method. At the stern detection line, the contribution rate of the wake magnetic field is the highest, reaching 0.7649. Along the radial detection line, the contribution rate of the shaft frequency magnetic field is the highest and gradually decays, eventually falling below the wake magnetic field at 150 m and remaining at an approximately 0.5 contribution rate. This study calculates the contribution rates under different operational conditions and detection scenarios, laying a technical foundation for research on the comprehensive active control strategies of submarine ELF magnetic fields in different scenarios.

Prognosis of disc herniated patients using back pain functional scale

Objective: Describe the clinical and magnetic resonance characteristics in patients with lumbar disc herniation and investigate the correlation between Back pain functional scale and clinical and magnetic resonance characteristics. Research subjects: 46 patients treated at Hue University of Medicine and Pharmacy Hospital from July 2023 to February 2024, with clinical symptoms suggestive of disc herniation and definitively diagnosed by magnetic resonance imaging lumbar spine. Research method: Cross-sectional descriptive study. Patients were examined clinically and had an MRI scan of the lumbar spine, assessed by the 12-factor Back pain functional scale (BPFS). Results: There is a difference between BPFS scores in patients with or without clinical symptoms. Finger-to-ground distance, Valleix sign, VAS score have a strong correlation with BPFS score. BPFS score has a strong correlation with the degree of spinal stenosis and there is a statistically significant difference in BPFS score between stenosis degrees (|r| = 0.97, p<0.05). Conclusion: There is a clinical correlation between BPFS and the degree of spinal stenosis on MRI in patients with lumbar disc herniation.

Effects of time-dependent and radiation on a tri-hybrid nanofluid flowing on stretchable/shrinkable cylinders with irregular heat generation/absorption using Ohmic heating

This work focuses on the non-linear dynamics of unsteady tri-hybrid nanofluids inside a thermally radiative, expandable or contractible cylinder, which has been a consistent subject of interest for contemporary researchers. An advanced model is formulated to address the unsteady external flowing of a conductive 50 %:50 % by volume aqueous solution of ethylene glycol-based ternary hybrid nanofluid (THNF) over a linearly stretched cylindrical structure, considering the significant applications of an anti-freeze agent in industrial, construction, nuclear, and mechanical domains. The proposed tri-hybrid nanomaterials consist of cobalt magnetite, titania, and magnesium oxide nanoparticles. The heat transfer rate is analyzed concerning viscous dissipation, Ohmic heating, and convective boundary conditions. This research examines the effects of magnetic and induced electric fields. The non-dimensional similarity model for the controlling partial differential system is derived using appropriate transformations and solved by the homotopy analysis technique (HAM) to get series solutions. In contrast to porosity and magnetic characteristics, the flow rate increases with increasing unsteadiness and electric factors. Close to the surface, the Nusselt number rises with an increasing unsteadiness parameter, but skin frictions diminishes. THNF has been shown to significantly enhance the cooling of cylindrical conduits and mechanical antifreeze agents.

Structural, electrical, leakage current, and magnetic characteristics of double perovskite Nd2NiTiO6

AbstractThis study investigates the structural, electrical, leakage current, and magnetic characteristics of the double perovskite material Nd2NiTiO6 synthesized through the sol–gel citrate auto‐ignition method. The Rietveld refinement of the X‐ray diffraction patterns confirmed a monoclinic symmetry (space group P21/n) with an ordered arrangement of alternate NiO6 and TiO6 octahedra. Impedance spectroscopic analysis exhibited the material's non–Debye‐type relaxation mechanism and semi‐conductive nature. AC conduction analysis revealed that the conduction of charge carriers occurs via the nonoverlapping small polaron hopping mechanism, consistent with Mott's variable range hopping model. Temperature‐ and frequency‐dependent dielectric measurements were interpreted using the Maxwell–Wagner interfacial polarization model. The analysis of thermal‐ and field‐dependent leakage currents established that conduction is ohmic, which the Schottky barrier model explains. Studies on magnetization ruled out the presence of magnetic ordering connected to indirect interaction between Ni2+ ions via Ti4+ ions and the rare‐earth cation (Nd3+) moment.

Study of the magnetic and structural properties of BaFe12 – xCuxO19 ferrites obtained by hydrothermal synthesis

Hexagonal ferrites of M-type (in particular, BaFe12O19) are magnetic materials with functional characteristics affected both by chemical composition and technology of their synthesis. We present the results of studying the magnetic and structural properties of BaFe12 – xCuxO19 hexaferrites (x = 0, 0.1, 0.2, 0.3, 0.4) obtained by hydrothermal synthesis with partial substitution of copper for iron. The composition of the synthesized samples was analyzed using X-ray diffraction, and the magnetic characteristics were measured using a vibration magnetometer. It has been revealed that the coercivity of the ferrite powders depends non-monotonically on the copper concentration and reaches the maximum (5629 Oe) and minimum (4698 Oe) values at x = 0 and x = 0.2. The presence of copper reduces the coercive force, but at the same time the values remain rather high compared to the results of similar studies. The saturation magnetization of the obtained ferrites gradually decreases (from 65.88 to 60.75 A · m2/kg at x = 0 and x = 0.4, respectively) with increasing. The distribution of Cu over ferrite sublattices was studied using Mössbauer spectroscopy. It is shown that in the hexaferrite structure, copper ions preferentially occupy 12k and 4f1 sites. Hence, a decrease in the saturation magnetization with increasing x is most likely attributed to the presence of side non-magnetic phases observed on X-ray diffraction patterns. It is also revealed that during synthesis, copper participates in the formation of low-melting phases on the surface of hexaferrite grains which promotes agglomeration of the particles. Thus, the resulting powders can potentially be sintered at lower temperatures and, therefore, without a significant increase in the size of crystallites. Herewith, the coercivity retains its original high values. The results obtained can be used in developing ferrite permanent magnets with improved characteristics.

Effect of Heat-Treatment Process on Magnetic Characteristics of Grain-Oriented Electrical Steel

This paper explores the effects and impacts of the metallurgical process of quenching on grain-oriented strips of electrical steel. Experimental findings reveal that quenching resulted in increased hardness and an increased Young’s modulus. An analysis of the material structure post-quenching indicates significant alterations in grain spacing and reduced height differences between grains. However, the magnetic properties of the steel deteriorated following quenching.

Magnetization processes features in the tapes of cobalt-based amorphous alloy

Studies of the amorphous cobalt-based soft magnetic alloy AMAG-172 (Co–Ni–Fe–Cr–Mn–Si–B) from different manufacturers have shown that in the as-quenched state there is nonuniformity of the magnetic characteristics, and therefore the level of internal stresses across the width of the tape produced by MSTATOR (Borovichi) significantly lower. However, similar to the tape produced by NIIMET (Kaluga), there is nonuniformity of the tape in thickness, which contributes to the formation of a bimodal field dependence of magnetic permeability.This may be a consequence of the non-uniform concentration along the width of the tape of hydrogen and oxygen atoms embedded in its surface during interaction with atmospheric vapor and the presence of temperature gradients during the manufacturing process. A stepwise shape of the initial sections of the magnetization curves in the region of the first maximum of magnetic permeability was discovered. The abrupt nature of the magnetization processes in the region of weak fields allows us to conclude that in the samples of tape produced by MSTATOR, the formation of the first maximum of the field dependence is associated with an independent magnetization reversal of the surface layer, while the main layer of the tape participates in the formation of the second maximum. The smoothed shape of the stepped initial section of the magnetization curve of samples produced by NIIMET corresponds to the gradual involvement of the main layer of the tape in the processes of magnetization and remagnetization. A comparison of the hysteresis loops of both parts of the tape, measured in the same magnetic field region, shows that the field shift of the hysteresis loops is associated with the interlayer interaction of the surface and volume of the tape, and the formation of asymmetric hysteresis loops occurs with the participation of the second layer with its gradual involvement in the processes of magnetization and magnetization reversal.

Flash combustion prepared Sm and Co doped Sr hexaferrite for environmental applications

AbstractNanotechnology is offering solutions to water contamination issues, as new techniques are needed to improve the removal of harmful compounds from water bodies. Despite previous reviews on this topic, nanotechnology is paving the way for more effective water treatment methods. Understanding the substitute influence of divalent Co2+ and rare earth elements Sm3+ on the structure, magnetic, and removal efficiency of hexagonal ferrites requires an understanding of a sequence of SrFe12O19, SrFe11.5Co0.5O19, Sr0.95Sm0.05Fe12O19, and Sr0.95Sm0.05Fe11.5Co0.5O19 M-type hexagonal ferrites were prepared using the flash technique. The XRD examination revealed that the crystallized material formed a single M-type hexagonal phase. The characteristics of M-type hexagonal ferrites include absorption bands with low wavenumbers in the FTIR curves between 400 to 1000 cm−1. There was a variation in magnetic characteristics with the replacement of Sm3+ and Co2+ doping, possibly due to the spin canting impact created by rare earth Sm3+ and Co2+ ions. The goal of the research is to explore the potential of doping magnetic hexaferrites and its influence in wastewater treatment. Various parameters, such as pH and contact duration, that influence the adsorption of lead ions from aqueous solutions were also examined. At pH 7 and 25 °C after 70min, the maximal removal efficiency of the Sr0.95Sm0.05Fe11.5Co0.5O19 was found to be 99%. Magnetic separation was carried out by applying an external magnetic field using a permanent magnet. The strong magnetization of the ferrites (51–58 emu/g) enabled the rapid separation of the magnetic particles from the solution, with over 95% of the ferrite particles being recovered within 10 to 70 min. The Freundlich isotherm model fitted all the isotherm data. Adsorption kinetics were explained by the pseudo-first-order, pseudo-second order, and intraparticle diffusion models. The investigated samples’ adsorption capacity remained efficient till 5 cycles.

MRI diagnosis of meningioma with marked skeletal hyperostosis and parenchymal infiltration in a 6‐year‐old standard poodle

AbstractA 6‐year‐old, neutered, male standard poodle was presented for evaluation of behaviour change. Neurological examination was consistent with a prosencephalic lesion. A magnetic resonance imaging study of the brain revealed a large non‐uniformly enhancing, extraparenchymal mass (9.2 × 8.7 × 5.0 cm) compressing the underlying brain parenchyma with heterogeneous T2‐weighted, T2‐fluid‐attenuated inversion recovery and T1‐weighted intensities. A meningioma with severe secondary hyperostosis and parenchymal invasion was identified on postmortem histological evaluation. To the authors’ knowledge, the presence of marked hyperostosis and calvarial infiltration to this degree, as well as the magnetic resonance imaging characteristics of these changes, have not previously been described in canine meningioma.

Modulation of electronic and magnetic characteristics of Ni and Cr-based transition metal halide monolayers using strain engineering

Modulation of electronic and magnetic characteristics of Ni and Cr-based transition metal halide monolayers using strain engineering

Unraveling the properties of [TPA]2Cu2Br6: A holistic investigation into structure, optics, magnetism and dielectric characteristics

The recent technological advances require an aligned innovation in the materials used for the construction of electronic devices. Hybrid materials play a important role in the optoelectronic applications because they combine both the organic and inorganic components To this end, the [TPA]2Cu2Br6 compound was successfully synthesized using the slow evaporation solution growth approach at room temperature. The [TPA]2Cu2Br6 compound crystallizes in the triclinic system with P1‾space group. The atomic arrangement can be described by an alternation of organic and inorganic layers stacked along the c direction and made up of [N(C3H7)4]+ and [CuBr3]− groups, respectively. The examination of SEM analysis allows us to raise the morphology and the good quality of the crystals. The EDX analysis was performed to ensure that all chemical elements were discovered and located in the relevant locations.For the compound under study, the UV–visible spectroscopy spectrum shows the direct band-gap value of ∼3.52 eV, indicating that it is a semiconductor material. Magnetic measurements revealed the superparamagnetic behavior. Studies of the dielectric constant permittivity ε*(ω) confirmed that the relaxation process was thermally activated. The dominant transport mechanism is the s the non-overlapping small polaron tunneling (NSPT) model.

Nuclear Magnetic Resonance Characterization and Analytical Modeling of Compressibility of Propped Fracture in Coal: New Insights

Nuclear Magnetic Resonance Characterization and Analytical Modeling of Compressibility of Propped Fracture in Coal: New Insights

A DFT theoretical prediction of new half-metallic ferromagnetism, mechanical stability, optoelectronic and thermoelectric properties of ZnCrO3 perovskites for spintronic applications

ZnCrO3 perovskites structural stability, optoelectronic, mechanical, along with thermoelectric properties, have all been to be described by calculations based on density functional theory (DFT). To determine the exchange correlation potential, the well-known generalized gradient approximation (GGA) and integration of the mBJ potential were used. The perovskite shows that this is in a cubic structure with Fm3m symmetry. Additionally, to check the stability, cohesive energy, structural optimization, and mechanical stability were requirements. This perovskite was found to be brittle, and their mechanical stability enhanced by the elastic constants. The perovskite has a half-metallic character, as evidenced by the spin-polarized electronic band profile, the behavior of the dielectric constant, and absorption coefficient in the spin-up and down channels. In this article, we also looked at magnetism and the origin of the half-metallic gap. The unpaired electrons in the split d-orbitals of the M-sited elements in the crystal field are responsible for the half-metallic as well as magnetic characteristics. Excellent spin polarization at the Fermi level encourages perovskite's possible use in spintronic technologies. Lastly, we computed the thermoelectric parameters within a chemical potential at various temperatures (300 K, 600, 900 K) to explore the potential application in spin electronic devices. Our finding shows that the ZnCrO3 alloy is exceptionally promising for the next generation of spintronics and thermoelectric devices at room and high temperatures.

Magnetic resonance imaging characteristics of musculoskeletal hydatid disease

Magnetic resonance imaging characteristics of musculoskeletal hydatid disease

An Innovative Water Splitting Process for a Sustainable In Situ Hydrogen Generation–Reduction of Nitrobenzenes Catalyzed by a New Bimetallic Nanocatalyst

ABSTRACTIn this research, bimetallic CdNi nanoparticles encapsulated in a magnetic spent coffee ground (Fe3O4@COFF/CdNi) was synthesized as a new nanocatalyst. The structural and chemical characteristics of Fe3O4@COFF/CdNi were comprehensively investigated using various techniques, including FT‐IR, XRD, XPS, TEM, VSM, EDS, TGA, BET, and ICP. Through XRD, XPS analysis, TEM images, and EDS mapping, the presence of CdNi nanoalloys was conclusively established. Fe3O4@COFF/CdNi exhibited remarkable catalytic activity for the hydrogen generation from water using iso‐propanol as a clean sacrificial agent. The high catalytic performance of Fe3O4@COFF/CdNi was attributed to the synergistic cooperative effect of Cd and Ni within CdNi nanoalloys. Interestingly, this process was performed for the in situ generated hydrogen from water to reduce a range of nitrobenzenes simultaneously into the corresponding anilines in high yields (93%–98%). The magnetic and hydrophilic characteristics of Fe3O4@COFF/CdNi facilitated its reusability over five runs. Using water as the most abundant hydrogen source, for the first time for in situ hydrogen generation–reduction of nitrobenzenes without demanding on external light sources or power supplies can be mentioned as a significant milestone of this field of study.

3D-printed polycaprolactone-magnetic nanoparticles composite multifunctional scaffolds for bone tissue regeneration and hyperthermia treatment

Cancer management after tumor resection is characterized by two critical needs: (i) rehabilitation of the resected tissue and (ii) preventing post-surgical tumor recurrence by destroying any residual tumors. The state of the art in literature is limited because it tackles these two major priorities individually, it achieves tissue regeneration via autologous grafting and prevents tumor recurrence through chemotherapy. In this paper, extrusion 3D printing has been employed to manufacture composite multi-functional scaffolds with polycaprolactone (PCL) as a polymeric matrix and magnetic nanoparticles (MNPs) in a 0 to 50 wt% ratio, that would aid in bone regeneration and cancer management via magnetic hyperthermia treatment. The fabricated scaffolds were evaluated for their mechanical, magnetic and thermal characteristics. The Young’s modulus of the scaffolds increased multi-fold with increasing concentration of MNPs added to PCL (26.88±9.02 MPa for pure PCL to 229.06±37.05 MPa for PCL/50 wt% MNP scaffolds). PCL/MNP scaffolds displayed a directly proportional correlation between MNP concentration and saturation magnetization. While the in vitro tests showed a statistically significant cell growth of human Mesenchymal Stem Cells (hMSCs) over 7 days for all MNP concentrations, only the 50% MNP scaffold showed an increase in temperature over 41oC when subjected to an alternating magnetic field making it suitable for the hyperthermia treatment. On application of alternating magnetic fields to PCL and PCL/50 wt% MNP scaffolds, there was an increase in hMSCs proliferation and decrease in Bone cancer cells proliferation, thus proving the potential to be used as a multi-functional scaffold for post-surgical bone cancer management.  

Comparative Analysis of Magnetic Field Distribution Characteristics of Two Shapes of Air-Core Bridge Arm Reactors

The application of air-core reactors in power systems is extensive and primarily aimed at enhancing system stability, limiting short-circuit currents, and providing reactive power compensation. Currently, the type most commonly used in power systems is the cylindrical-shaped air-core reactor (CAR), known for its stable mechanical structure and mature manufacturing process. However, the external magnetic field generated by this reactor propagates over a considerable distance in the air, which can interfere with the normal operation of many power electronic devices. This paper presents a comparative analysis between a novel annular-shaped air-core bridge arm reactor (AABAR) and the widely used cylindrical-shaped air-core bridge arm reactor (CABAR) within a DC transformer system. The comparison focuses on the magnetic field distribution, including magnetic flux density, magnetic field radiation range, and magnetic field energy, as well as the attenuation characteristics of these physical quantities. The concept of magnetic clearance (MC) is introduced as a quantitative metric. Through finite element simulation software (AEDT 2021 R1), it is demonstrated that the annular-shaped air-core reactor design can significantly improve spatial utilization and reduce the actual usage space of the reactors in DC transformer systems.