Nanomagnetic Materials Research Articles

Development of a Fast and Efficient Strategy Based on Nanomagnetic Materials to Remove Polystyrene Spheres from the Aquatic Environment

Microplastics contamination is growing globally, being a risk for different environmental compartments including animals and humans. At present, some Spanish beaches and coasts have been affected by discharges of these pollutants, which have caused a serious environmental problem. Therefore, efficient strategies to remove microplastics (MPs) from environmental samples are needed. In this study, the application of three magnetic materials, namely iron oxide (Fe3O4) and the composites Fe3O4@Ag and Fe3O4@Ag@L-Cysteine, to remove MPs, specifically polystyrene (PS), from water samples has been assessed. The magnetic nanoparticles were synthesized and characterized by field effect scanning electron microscopy with energy dispersive X-ray spectroscopy detection (FESEM-EDX). Experimental conditions such as temperature, time, and pH during the removal process were assessed for the different adsorbent materials. The removal rate was calculated by filtering the treated water samples and counting the remaining MPs in the water using ImageJ software. The strongest removal efficiency (100%) was shown using Fe3O4@Ag@L-Cysteine for PS at 50 mg L−1 within 15 min of the separation process at room temperature and a neutral pH. A thermodynamic study demonstrated that the developed MPs elimination strategy was a spontaneous and physisorption process. Coated Fe3O4 magnetic nanoparticles were demonstrated to be an efficient adsorbent for MP removal in aquatic environments and their use a promising technique for the control of MPs contamination.

Enhanced Removal of Cr (VI) by PEI/nFe3O4 Ultrafiltration Membranes Using Peristaltic Pump-Driven Dynamic Adsorption

In this study, Fe3O4 nanoparticles (nFe3O4) were loaded onto polyvinylidene fluoride ultrafiltration membranes and capped with polyethyleneimine in order to form PEI/nFe3O4 ultrafiltration membranes. We used a peristaltic pump as a driver for dynamic adsorption, and the PEI/nFe3O4 ultrafiltration membrane had a good ability to remove hexavalent chromium (Cr(VI)) from wastewater. The full permeate volume of the PEI/nFe3O4 ultrafiltration membrane was maximized at pH 3. Meanwhile, the removal of Cr(VI) from the wastewater reached 98% and reduced to trivalent chromium (Cr(III)). When the initial concentration of Cr(VI) increased, the active sites on the membrane would be filled and the removal efficiency of Cr(VI) would decrease. Meanwhile, the coexisting ions affect the removal efficiency of Cr(VI), and PO43- has a strong negative effect on the removal efficiency. PEI/nFe3O4 ultrafiltration membrane is an effective combination of multifunctional nanomagnetic materials and membrane materials, which can effectively remove hexavalent chromium from wastewater. The study provides a basis for future applications in the environmental remediation of low-concentration chromium-containing wastewater.

La3+ ion doped Cd0.5C0.5LaxFe2-xO4 nanomagnetic materials for high-frequency device applications

The sol-gel self-combustion technique was applied to form Cd–Co-based La-doped (Cd0.5Co0.5LaxFe2-xO4) spinel ferrite nanoparticles. A series of six samples was synthesized by varying lanthanum content from x = 0.00 to 0.20. The structural characteristics of the prepared nanoparticles were carried out using X-ray diffraction (XRD) analysis. The (311) plane verified that the prepared nanomaterials are in the spinel phase in all observed XRD patterns. The crystallite size for each sample was determined using the Scherrer formula found in the 8.7–17.8 nm range, which is well correlated with the SSP model. The crystallite size decreased while the lattice constant increased from 8.38 to 8.45 Å with increasing La-content. The increasing trend in the bulk density and X-ray density has been analyzed with the effects of La3+ contents. In Fourier-transform infrared spectroscopy (FTIR), the high-frequency absorption band (υ1) was found from 522.15 to 541.06 cm−1, whereas the low-frequency band (υ2) varied from 419.80 to 414.31 cm−1. The surface morphology was carried out by scanning electron microscope (SEM), which positively correlated with XRD analysis. Impedance analyzer (IA) assisted in observing the variations in complex dielectric properties of the compound in the frequency range from 1 MHz to 3 GHz. The dielectric constant and impedance plots depicted that the nano ferrites have good dielectric properties in low-frequency regions due contribution of polarization. While conduction can be made possible in the high-frequency areas as observed through AC conductivity. The electric modulus revealed the relaxation phenomenon at high frequency due to the hopping of electrons at the octa and tetrahedral sites. The magnetic properties were investigated to study the impact of La3+ ion under the applied magnetic field from −15 to 15 kOe. The saturation magnetization, and magnetic remanence were found from 40.6 to 27.7 emu/g and 19.6 to 2.7 emu/g, respectively. The synthesized nanoparticles can be utilized for microwave applications and magnetic storage devices.

Structural, electrical, dielectric, magnetic, and microwave absorption properties of Cr substituted BaSrCo2Fe12O22 hexaferrites for high-frequency applications

In the recent decade, advancements in technology and the excessive use of electronic devices in everyday life have harmed human health and produced electromagnetic pollution. To overcome these problems, hexagonal ferrites are used as excellent microwave-absorbing materials to clean the environment and protect human health. In this study, chromium (Cr3+) substituted Y-type BaSrCo2CrxFe12-xO22 hexaferrites (x = 0.0, 0.5, 1.0, 1.5, and 2.0) have been synthesized through self-ignited sol-gel method and sintered at 1150 °C for 5.5 h. The single phase of the synthesized nanomagnetic materials was confirmed by X-ray diffraction analysis. FTIR analysis unfold the Fe–O vibrational bands at tetrahedral and octahedral sites due to iron oxide base material. The incorporation of Cr3+ limits the transfer of electrons. As a result, DC electrical resistivity significantly increases from 7.59 × 109–4.85 × 1010 (Ω cm). The dielectric behavior and impedance analysis was carried out in the 1 MHz - 6 GHz range. By replacing Cr3+, the dielectric constant and loss exhibit a decreasing behavior. For all compositions, the values of reflection loss are calculated in the range of −39.37 to −32.95 to make them excellent microwave-absorbing materials due to their lower cost, small size, and lightweight properties. The substitution of Cr3+ increases the saturation magnetization (61.35–96.10 emu/g), coercivity (62.31–897.99 Oe), and remanence (12.30–46.52 emu/g). An increase in the coercivity value indicated that samples are thermally stable and suitable for perpendicular magnetic recording media.

Harnessing Nanotechnology for Advancements in Magnetism: Current Trends and Future Prospects

Nanotechnology has revolutionized various fields, including magnetism, by enabling the manipulation of materials at the nanoscale. This paper explores the current trends and future prospects of harnessing nanotechnology for advancements in magnetism. We discuss the fundamental principles of magnetism at the nanoscale and review recent developments in nanomagnetic materials, fabrication techniques, and applications. Additionally, we highlight the potential impact of nanotechnology on diverse areas such as data storage, biomedical devices, magnetic sensors, and spintronics. Furthermore, challenges and opportunities in the field are addressed, offering insights into the direction of future research and technological innovations.

Multifunctional smart engineering nano magnetic materials with ultrahigh synergetic adsorption-photocatalytic performance

Water contamination by organic dyes is a severe environmental and health issue requiring a sustainable remedial solution. Among different acid dyes, the Acid Violet-19 (AV-19) extensively used for the coloring of fabrics has toxic and carcinogenic effects, which need to be effectively treated with state-of-the-art photocatalysts and techniques. In the present work, a series of nanomagnetic spinel ferrites (MFe2O4: M = Mg, Ca, Mn, Ni, Zn, and Cd) were synthesized for dye remediation through a facile combustion route. The synthesis involved the pioneering use of DL-Glutamic acid as a fuel due to low ignition temperatures (200–250 °C), cost-effectiveness, and environmental compatibility. The nanomagnetic particles with d90 < 200 nm and crystallite sizes lower than 50 nm were synthesized, exhibiting strong superparamagnetic properties and high surface areas. The synthesized nanoparticles exhibited ultrahigh adsorptive elimination and superior photocatalytic degradation of AV-19 under high concentration (250 and 100 mg/L) conditions. High monolayer absorbance capacities of 3905, 1061, and 814 mg/g were achieved for CaFe2O4, MgFe2O4, and CdFe2O4. The AV-19 elimination is well described by the Langmuir isotherm and second-order kinetic model. The dipole-dipole and Yoshida H-bonding interactions are the proposed adsorption mechanisms. The ZnFe2O4 showed exceptionally high photocatalytic dye degradation (∼ 100 % within 1 h), with the first-order kinetic rate constant being 0.063 min−1 at a photocatalyst dose of 0.1 g/L. The synthesized catalyst also showed high removal-degradation efficiency against different cationic and anionic dyes, including Malachite green, crystal violet, and Titan yellow. The solution pH showed an insignificant effect on the synergetic adsorption and photocatalytic degradation efficiency of MFe2O4. The present study shows that synthesized magnetic nanoparticles through the facile combustion route effectively eradicate the dye pollutants from wastewater.

Cluster helicates: promising functional materials.

Cluster helicates are a new type of supramolecular architecture that consists of a metal cluster wrapped around by ligands arranged in a helical mode. This class of compounds combines the unique properties of metal clusters with the sophisticated chiral arrangement found in helicates. Therefore, these architectures show promising applications in the development of advanced materials with specific electronic, magnetic, optical, catalytic and biological properties. This review delves into a few pioneering studies on cluster helicates and their applications as nanomagnetic, nanoelectric and catalyst materials. Furthermore, it emphasises the necessity for further exploration in this area and the fields related to the functional applications that cluster helicates can bring to the future of materials science.

Research progress and practical application of magnetic composite absorbing materials

The update and iteration of communication technology, the continuous emergence of new electronic devices, smart home appliances and new energy vehicles, and the widespread use of military electromagnetic technology have caused serious electromagnetic radiation problems. Nanomagnetic materials have special electromagnetic properties and become the continuous research object of absorbing materials, especially in the development of low-frequency absorbing materials. This paper reviews the theoretical basis and research status of nanomagnetic materials in low-frequency absorbing materials and composite absorbing materials that are "thin, light, wide, and strong". In addition, the basic research is aimed at realizing the final application, and this paper also summarizes the application status of the absorbing agent in practical application.

나노 자성체 내 스핀 구조체의 3차원 특성

나노 자성체 내 스핀 구조체의 3차원 특성

Complex field reversal dynamics in nanomagnetic systems

Nanomagnetic materials, built from thin, patterned films of ferromagnetic materials, began as analogues to frustrated magnetism. Their low energy of operation and emergent properties make them strong candidates for physics-based devices. A recent model of how nanomagnetic domains flip, the Glauber mean-field model, is used here to understand how systems of nanomagnets evolve when opposed by external field. This reversal can be expressed in an analytical form in the case of one-dimensional chains and trees at zero temperature, where the cascade of spin flips gives rise to harmonic power spectra. The same cascades in two and three dimensions form fractal field reversal clusters whose shape depends on the strength of the field and the tuning of interactions between nanomagnets.

Synthesis and applications of double metal MXenes: A review

MXenes are known as a new type of two-dimensional layered materials that are composed of carbide, nitride, or carbonitride of transition metals. In the recent discovery of a new class of MXenes, two transition metals occupy the metal site, called double transition metal MXenes (DTM). These multilayer composites are of interest due to their attractive features such as high ion transport, extensive surface area, and biocompatibility. Some computational methods are used to predict the properties and performance of bimetallic carbonitrides. The most important feature of this category of materials is the stability and amount of formation energy, which directly affects the choice of material in various applications. Density functional theory (DFT) calculations are very beneficial to estimate the thermodynamic stability of DTM MXenes. Of course, proper surface modification with stable terminals is needed to overcome the limitations of DTM MXenes. In this review, the electrochemical, metallic, and magnetic properties of DTM MXene have been presented first. In the following, preparation methods are summarized according to the latest published findings. Then, various applications including hydrogen evolution reactions, anode materials in lithium and sodium batteries, nanomagnetic materials, and special applications have been investigated. Finally, more challenges, prospects, and suggestions for the development of two-dimensional DTM MXenes have been presented.

A Method for Preparing Superparamagnetic Nanomaterial

Substances with superparamagnetism, a special magnetic effect, are magnetized under external magnetic field. When the applied magnetic field disappears, superparamagnetic substances have almost zero magnetization intensity, with quite small coercivity. The performance of magnetic powder or magnetic suspension used in magnetic particle detection greatly affects detection sensitivity. This paper studies a new method for preparing nano-superparamagnetic non-destructive testing materials by combing membrane technology and chemical co-precipitation method. Magnetic nano-ferroferric oxide particles were prepared by preparing membrane reactor based on chemical co-precipitation method to find the optimal synthesis conditions for nano-ferroferric oxide particles. Polymer nano-magnetic materials with good dispersibility, superparamagnetism, high dispersibility, uniform particle size distribution were obtained, which can well detect cracks, especially small cracks. It is a good magnetic nondestructive testing material.

Multifunctional flower-like core-shell Fe/Fe4N@SiO2 composites for broadband and high-efficiency ultrathin electromagnetic wave absorber

The nano-iron nitride soft magnetic material has excellent magnetic properties and is expected to be a brilliant electromagnetic wave absorber. However, how to fully exploit its wave-absorbing potential remains a thought-provoking question. Here, we have synthesized Fe/Fe4[email protected]2 nanomagnetic core-shell materials with different Fe/Fe4N ratios by performing nitridation reactions at different temperatures. Then, the flower-like core-shell Fe/Fe4[email protected]2 structure was obtained by the etching method. Finally, with the synergy of the excellent magnetic and dielectric losses, an outstanding absorption performance could be achieved with a minimum refection loss (RLmin) of −71.31 dB at the matching thickness of 1.4 mm, and the widest effective absorption bandwidth (EABmax) of 6.1 GHz less than −10 dB was realized at 1.16 mm. Moreover, this material also shows a preeminent advance in corrosion resistance to adapt to harsh environments. Hence, this iron nitride flower-like core-shell structure exhibits great potential in microwave absorption in harsh conditions.

Modulation of Magnetic Exchange Coupling via Constructing Bi- or Multimagnetic Heterointerfaces

How to resolve contradictions between the nanoscale size and high saturation magnetization (Ms) remains one of the scientific challenges in nanoscale magnetism as the theoretical optimal Ms of nanocrystals is compromised by the surface spin disorder. Here, we proposed a novel nanotechnology solution, heterointerface constructions of exchange-coupling core-shell nanocrystals, to rearrange the surface spin for the enhancement of Ms of nanomagnetic materials. As a demonstration of this principle, single-interface coupling FePt@Fe3-δO4 core/shell nanocrystals and multi-interface coupling FePt@Fe3-δO4@MFe2O4 (M = Mn or Co) core/shell/shell nanocrystals were synthesized. The simulated and experimental results demonstrated that constructing coupling heterointerfaces orientates the overall magnetic moment, ultimately enhancing the Ms of nanomagnetic materials. Moreover, this work first demonstrated that the origin of coupling heterointerfaces arose from mismatched lattices rather than chemical composition mismatch at the core-shell interfaces, thus providing both a solution to unite different mechanisms and an explanation to explain the exchange coupling at heterointerfaces.

The road to 3-dim nanomagnetism: Steep curves and architectured crosswalks

Nanoscience and its associated nanotechnology started several decades ago to discover and harness properties and behavior of materials that occur due to lowering their dimensionality. Nanomagnetism, which is the branch of nanoscience to investigate magnetic properties of materials down to fundamental length and time scales led to the discovery of a plethora of novel nanoscale spin phenomena and has further laid the groundwork for spintronics, which has become the primary enabler for the most advanced information technologies, including magnetic storage and sensor devices.So far, low-dimensional magnetic systems have been confined to zero (quantum dots), one (nanowires), and two (thin films) dimensions, however, recently research with artificially designed three-dimensional magnetic systems is emerging as it opens the path to novel scientifically exciting phenomena with enormous technological potential to advance spintronics further towards ultrasmall, ultrafast and most importantly low-power electronics.These three-dimensional structures harness the scientific achievements from traditional nanomagnetism, but expand them in a tailored way into the third dimension. Local curvature, particular when defined in a rather broad sense, including geometrical curvature adds to a traditional 2D film a third dimension and proximity effects drawing upon the 3D environment are among the design principles for those 3D magnetic systems.This critical focus article reviews briefly the current state-of-the-art of the emerging research topic with 3D nanomagnetic materials, and describes some of the challenges that the research community needs to address in terms of synthesis and fabrication, theory and modelling, as well as characterization and validation to ultimately bring to bear potential applications with 3D nanomagnetic devices.

DIFFERENTIAL METHOD OF QUALITY CONTROL OF PHYSICO-MECHANICAL CHARACTERISTICS OF KNITTED FABRIC FOR BATHING SUIT

The actuality of the introduction of textile materials with the content of nanopowders based on oxides of divalent and trivalent iron has been proven. The main directions of implementation of such materials into real practical results are shown. The algorithm for the synthesis of magnetic nanomaterials was developed. Adhesion properties of magnetic nanopowders to textile fibers are determined. It is shown that exposure for 5 – 7 days ensures almost absolute adhesive resistance and provides a combination of textile properties with magnetic nanopowders. Bacteriostatic properties of nanomagnetic textile materials were determined. For this purpose, the growth dynamics of mold fungi was determined. It is shown that the content of nanomagnetite significantly suppresses the growth of mold infections. The magnetic properties of textile materials are described, the possibilities of their introduction into elements of smart clothing, medical and protective materials are determined. Magnetic technologies in medicine, compression elements of clothing can be provided with the help of magnetic textile materials. The magnetic effects of such materials make it possible to create elements of clothing with a change in geometry. This determines the possibility of using such materials for smart clothes with new effects. The possibilities of creating magnetic nanomaterials with given structural characteristics have been proven. The addition of nanopowders reduces the size dispersion of structural elements, reduces their size, and increases density. This effect allows ensuring the specified transfer characteristics of textile materials, which provide the necessary parameters of heat transfer and mass transfer. The possibilities of using magnetic textile materials against electromagnetic radiation are shown. The structure of directions for the use of magnetic textile materials for medical and protective products, as well as for promising elements of smart clothing, has been developed.

Bi3+ and V3+ co-substituted Ni-Co spinel ferrites: Synthesis, optical, magnetic characterization and hyperfine interaction

Ni0.5Co0.5VxBixFe2-2xO4 spinel ferrite nanoparticles with composition (x = 0.00, 0.02, 0.04, 0.06 and 0.08) (CoNiVBiFeO (x = 0.00–0.08) SFNPs) were well fabricated hydrothermally. The consequence of co-substitution of both Bi3+ and V3+ ions on structure, morphology, and magnetic features of Ni0.5Co0.5Fe2O4 SFNPs were studied using XRD (X-ray diffractometry), scanning (SEM) and transmission (TEM) electron microscopies along with EDX, XPS (X-ray photoelectron spectroscopy), VSM (vibrating sample magnetometry) and Mossbauer spectroscopic techniques. The pure spinel ferrite (SFs) phase was approved via XRD. The morphology of SFNPs were revealed by SEM and TEM. Hyperfine parameters are determined from fitting room temperature Mössbauer spectra. The V3+ and Bi3+ ions occupy mainly at B site. The isomer shift values are coupled with the characteristics of the high spin Fe3+ ion. The influence of V3+ and Bi3+ ions co-doping on the magnetic features of Ni-Co SFNPs has been also investigated at 300 and 10 K. The saturation magnetization (Ms), remanence (Mr), coercive field (Hc), and Bohr magneton number (nB) are extracted from the recorded M-H hysteresis loops. Nanomagnetic materials with x content of 0.02, 0.08, and 0.10 exhibited superparamagnetic (SPM) behavior, whereas other products with x content of 0.00, 0.04, and 0.06 displayed soft ferrimagnetic behavior at ambient temperature. The different prepared nanoferrites displayed hard ferrimagnetic characteristic at 10 K. The Ms and Mr values are decreased as result of V3+ and Bi3+ ions co-doping. However, Hc does not show a monotonic trend. The fluctuations in magnetic moments of ions, super-exchange coupling, and distribution of cations are correlated with the changes in magnetic parameters to explain their variations.

Uncertainty Propagation in Quantitative Magnetic Force Microscopy Using a Monte-Carlo Method

A Monte-Carlo (MC)-type method is utilized for the propagation of uncertainties in quantitative magnetic force microscopy (qMFM). In qMFM, quantitative magnetic field distributions are inferred from magnetic force microscopy (MFM) raw data using a calibration of the instrument point spread function and a subsequent inversion process. The two stages of calibration and measurement may be subject to a variety of uncertainties that naturally arise in practice. Identifying these sources of uncertainties and quantifying their impact on the reconstruction of the measurand is crucial for reliable quantitative studies of nanomagnetic materials and devices. So far, the propagation of variance method has been applied to determine the uncertainty budget for a complete calibration and measurement process. In this work, we are able to improve the uncertainty description in terms of structure and magnitude by application of an MC method. We demonstrate the importance of correlations and show possible side effects of model linearizations.

Device for Simulating Fluid Microgravity Environment Based on Magnetic Compensation Method and Research on Magnetic Fluid Lubrication Performance of Oil Film Bearing

At present, with the rapid development of the material market, the requirements of high performance and high precision of materials are increasingly exposed. Nanomagnetic fluid materials are more and more widely used in oil film bearings, but their compressive strength and performance are insufficient, which is difficult to meet the current requirements of material chemical properties. First of all, a device for simulating a microgravity environment with magnetic compensation is fabricated. Then, in the microgravity environment, according to the different proportions of magnetic solid particles, the base carrier liquid and the surfactant are mixed to produce nanomagnetic fluid and the nanomagnetic fluid with different composition proportions is prepared by adjusting the proportion of ferrous and ferric ions. Finally, the lubrication performance of oil film-bearing magnetic fluid with different composition ratios was tested. The results show that when the ratio of Fe2+ to Fe3+ is between 11 : 20 and 13 : 20, the MHD (magnetohydrodynamics) lubrication performance of oil film bearing is in the peak region. When the ratio is 3 : 5, the best lubrication performance can be achieved. When it is slightly higher than this ratio, the oxidation rate is accelerated due to more ferrous ions. Although it can have a good lubrication effect, it is easy to cause the overall fluidity of oil film-bearing magnetic fluid to deteriorate. Therefore, the oil film bearing nano-MHD with the ratio of 3 : 5 ferrous to ferric has the best lubrication performance in the microgravity environment simulated by magnetic compensation. Experiments have shown that when the magnetic fluid is heated in a magnetic field, the temperature gradient will cause the magnetization to change, which makes the magnetic force experienced by the liquid in each part different, causing convection. Therefore, by selecting the direction of the magnetic field and the heating surface, by applying an external magnetic field or promoting convection, or suppressing convection, convection in the opposite direction to the natural convection of gravity can also be realized. Moreover, magnetism can immediately promote high-temperature boiling, generate bubbles, and eliminate the generation of bubbles to promote heat transfer. With the above effects, the heat conduction between the heating wall and the liquid can be controlled, and its practical and potential application fields are very wide.

One-pot, facile synthesis and fast separation of a UiO-66 composite by a metalloporphyrin using nanomagnetic materials for oxidation of olefins and allylic alcohols

One-pot facile synthesis of a new composite based on the incorporation of a metalloporphyrin within the UiO-66 metal–organic framework is reported.