Magnetic Properties Research Articles

Blood cell separation with magnetic techniques: a critical review.

Blood cell separation is a critical process for many clinical and research applications. Among the various techniques employed for blood cell isolation, magnetic techniques are very attractive due to their multiple benefits, i.e. high efficiency, simplicity, low-cost, and no need for expensive equipment or trained operators. Microfluidic devices integrating magnetophoresis have demonstrated promising results for high-throughput separation, with some achieving separation rates of over 108 cells per hour. However, there are many different approaches that can be used for blood magnetic separations, with the selection depending on the sample properties, target cells and purpose of the isolated fractions. This critical review examines recent advances (2014-2025) in magnetic techniques for separating blood cells. Both labeled and label-free approaches are analyzed, with a focus on their performance and impact on cellular function, highlighting their strengths, limitations, and potential for future development in clinical research applications. Among the labeled approaches, positive selection methods have been shown to achieve high purities for various cell types; nevertheless, these techniques might affect cell functionality after separation. Therefore, negative selection can be used for the separation of cells when cellular functionality needs to be preserved. Moreover, label-free techniques, primarily focused on red blood cells (RBCs) separation, can be used for blood cell isolation by leveraging the cells' intrinsic magnetic properties. These methods showed potential for continuous, high-purity RBCs separation, with some devices achieving over 95% recovery and purity. This work aims to provide valuable guidelines for the appropriate selection of magnetic technologies for blood separations to accomplish the successful implementation of magnetophoresis in clinical practice.

Enhanced visible-light-driven photocatalytic potential of magnetic NiMnFeO4/g-C3N4 nanocomposites for degradation of aqueous organic pollutants: Schiff-base ligand-assisted sol–gel auto-combustion synthesis, characterization and mechanism analysis

Globally, the contamination of aquatic systems and wastewater by dyes is highlighted as a critical concern for human beings. Therefore, it is necessary to construct novel heterostructure photocatalysts with broadened light absorption range and enhanced charge transfer rates. The primary objective of this research is to achieve the NiMnFeO4 phases through an auto-combustion route with exploring various Schiff base ligand’s effects such as H2Salen, H2Salpn, and H2Salophen on crystalline structural and morphological features. Following this, a composite of NiMnFeO4 nanoparticles and graphitic carbon nitride (g-C3N4) nanosheets was synthesized via a sonochemical-assisted co-precipitation process, in which diverse weight proportions of nano-NiMnFeO4 was employed. To unveil the crystalline structure, chemical composition, morphology and magnetic properties of NiMnFeO4/g-C3N4 nanocomposites, multiple spectroscopic and microscopic techniques were carried out. The outcomes displayed that pure NiMnFeO4 phase synthesized in the presence of H2Salpn have optical bandgap energy of 2.0 eV and morphologically desirable nano-sample. The photocatalytic efficiencies and kinetic investigation of as-obtained NiMnFeO4, g-C3N4 and various NiMnFeO4/g-C3N4 nanocomposite’s types were perused through degradation of cationic malachite green and anionic eosin dyes under visible light irradiation. The content of nano-NiMnFeO4 in binary component systems changed the yields of the photocatalytic process and NiMnFeO4/g-C3N4 (0.25:1) nanocomposites revealed highest eosin degradation proficiency (95.12%) in visible region after 120 min. Furthermore, the proposed mechanism underlying eosin degradation via photocatalytic activity was thoroughly investigated via reactive species scavenging experiments. In photoreactions conducted by optimum NiMnFeO4/g-C3N4 (0.25:1) sample, both hydroxyl and superoxide radicals performed the superior role for the photocatalytic breakdown of eosin below visible lamp.

Ferroelectric Control of Anisotropic Magnetoresistance in Ultrathin Sr2IrO4 Films toward 2D Metallic Limit

AbstractThe Ruddlesden‐Popper 5d iridate Sr2IrO4 is an antiferromagnetic Mott insulator with the electronic, magnetic, and structural properties highly intertwined. Voltage control of its magnetic state is of intense fundmenatal and technological interest but remains to be demonstrated. Here, the tuning of magnetotransport properties in 5.2 nm Sr2IrO4 via interfacial ferroelectric PbZr0.2Ti0.8O3 is reported. The conductance of the epitaxial PbZr0.2Ti0.8O3/Sr2IrO4 heterostructure exhibits ln(T) behavior that is characteristic of 2D correlated metal, in sharp contrast to the thermally activated behavior followed by 3D variable range hopping observed in single‐layer Sr2IrO4 films. Switching PbZr0.2Ti0.8O3 polarization induces nonvolatile, reversible resistance modulation in Sr2IrO4. At low temperatures, the in‐plane magnetoresisance in the heterostructure transitions from positive to negative at high magnetic fields, opposite to the field dependence in single‐layer Sr2IrO4. In the polarization down state, the out‐of‐plane anisotropic magnetoresistance RAMR exhibits sinusoidal angular dependence, with a 90° phase shift below 20 K. For the polarization up state, unusual multi‐level resistance pinning appears in RAMR below 30 K, pointing to enhanced magnetocrystalline anisotropy. The work sheds new light on the intriguing interplay of interface lattice coupling, charge doping, magnetoelastic effect, and possible incipient ferromagnetism in Sr2IrO4, facilitating the functional design of its electronic and material properties.

The features of two approaches to describe magnetic anisotropy in non-grain-oriented electrical steels

Purpose This paper strives at getting deeper insight into possible methods to take anisotropy of magnetic properties of non-oriented steels into account. The first considered approach is derived from considerations from metallurgy and materials science. It offers a straightforward way to compute variations of magnetic properties from measurements defined for three cutting angles of the samples. The second method is based on some concepts from electromagnetic theory. This approach allows one to determine the relationships between vectors, and, thus, it is more useful from a perspective of an electrical engineer. One of the goals of the paper is to show the flexibility of the second approach, which offers a lot of information on the relationships between the above-mentioned vectorial quantities. Design/methodology/approach The approach based on orientation distribution functions is based on the assumption that many angular dependencies of physical quantities may be recovered from the knowledge of material behaviour in three well-defined directions. The method is directly applicable, e.g. to power losses, permeability at loop tip, coercive field strength, etc. The other method is derived from earlier research focused on approximating coenergy profiles. The modified elliptical model by Biró et al. (2010) used previously for material with more distinctive anisotropy (grain-oriented steel) is applied to non-oriented steel, which – in spite of its name – also exhibits a substantial anisotropy level. Findings The advantage of the first model is its simplicity. It offers a reasonable modelling accuracy; the discrepancies between the measured and the modelled values of the considered quantities did not exceed 10%. The second approach is more complicated; on the other hand, it provides information about spatial dependencies between vectors H→ and B→. It was found that the value of exponent n in the relationship from which the magnitude of the vector is determined is somewhat higher for the considered material than the value proposed by Biró et al. This effect may be related to a different morphology of the examined materials. The discrepancies between model predictions and measurement values were below 15%. The computations in the present study were carried out in a wider range of working flux densities than were originally considered by Biró et al. Research limitations/implications Anisotropy of magnetic properties may and should be taken into account also in the case of non-oriented electrical steels. This can be achieved during the design of magnetic circuits with the use of the presented models. In the present paper, we have used piecewise linear interpolation schemes to describe anhysteretic curves for two principal directions; however, more sophisticated approaches might be used instead, which in turn might improve the accuracy of the second model. Originality/value The modified elliptical model allows one to determine a number of important relationships for the considered non-oriented electrical steel. Therefore, it might be a useful tool at the design stage. A number of tedious measurements may be avoided. The authors believe that the method is also applicable to grain-oriented electrical steel.

Synthesis of new Cu(II), Ni(II), and Cd(II)-(N-Glycyl-L-leucine) complexes as peptide metalloantibiotics for targeting pathogenic water with antioxidant effect investigation

BackgroundIn recent efforts to address the critical need for clean and portable water, we have focused on innovative methods to eliminate pathogenic microorganisms. To this aim, the N-Glycyl-L-leucine (Gly-Leu) peptide ligand was complexed with different transition metal ions [Cu(II), Ni(II), and Cd(II)] as new peptide metalloantibiotics. The compounds were characterized and examined using various analytical methods, including elemental analysis (CHN), Fourier transform infrared spectroscopy (FTIR), assessments of magnetic properties, molar conductivity, 1HNMR, thermogravimetric analysis (TGA), and mass spectroscopy. The ligand acted as a di-anionic molecule using the carboxylate and the deprotonated amide nitrogen atom. The coordination sites were completed with carbonyl oxygen atoms and a water molecule. The complexes showed polymeric structures using bridging carboxylate groups.ResultsThe antibacterial properties of the synthesized metal chelate were evaluated using disk diffusion and minimum inhibitory concentration methods on bacterial organisms identified from water samples taken from the Nile River. At a 1 mg/mL dose, the Cu(II)-chelate showed the biggest inhibitory zone of 27 mm against Klebsiella pneumonia, with a MIC value of 62.5 μg/mL, greater than that of the common gentamicin medication. Molecular docking investigations supported these findings, showing that Cu(II)-chelate had the lowest binding energy of − 6.16 kcal/mol, indicating significant, beneficial interactions with the amino acids in the active region of bacterial proteins. Furthermore, the Cu(II) complex and the COVID-19 main protease showed encouraging results in the docking analysis, indicating that the complex may have antiviral properties and be able to inhibit viral propagation successfully. The metal chelates demonstrated noteworthy antioxidant activity, especially against 1,1-diphenyl-2-picrylhydrazyl (DPPH radicals). The IC50 values of the antioxidant assay for Ni(II) and Cu(II) chelates were extremely similar to ascorbic acid, a common antioxidant. Their notable antioxidant capacity was demonstrated by the IC50 values of (14.4, 15.5, and 18 µg/mL) for ascorbic acid, Ni(II), and Cu(II) chelates, respectively.ConclusionsOur study successfully demonstrated the potential of a new Gly-Leu peptide ligand complexed with transition metal ions, particularly Cu(II), in eliminating pathogenic microorganisms from water. Cu(II)-chelate exhibited superior antibacterial properties, as confirmed by both experimental and molecular docking results. The chelates also displayed noteworthy antioxidant capacity, comparable to that of ascorbic acid. Additionally, the Cu(II)-chelate demonstrated promising antiviral potential, theoretically interacting effectively with the COVID-19 main protease, which suggests its ability to inhibit viral replication. These results underscore the potential of Cu(II)-chelate as a multi-functional compound with applications in water purification and therapeutic fields.

Preparation and characterization of an algal-based magnetic biochar nanocomposite for the removal of azocarmine G2 dye from aqueous solutions

Dyes are released into bodies of water as the textile industry expands in response to the growth of the global population. These textile dyes have severe effects on the environment, including wildlife, terrestrial species, and humans. This study explores the synthesis, characterization, and application of an algal-based magnetic biochar nanocomposite for the efficient adsorption of azocarmine G2 (ACG2) dye from aqueous solutions. The magnetic biochar (Fe3O4@BC) was characterized by Raman spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectrometry (FTIR). Batch adsorption experiments were performed to assess the impact of the initial dye concentration (25 to 100 mg / L), contact time (up to 300 min), pH (1–3) and temperature (298 to 328 K). The nano-composite achieved a maximum adsorption capacity (qmax) of 71.3 mg/g at pH 1, with equilibrium reached within 240 min. Adsorption kinetics followed a pseudo-second-order model (R2 = 0.99), while isotherm analysis fit well with the Langmuir model (R2 = 0.98), indicating monolayer adsorption. However, the Freundlich model provided a better fit, indicating that the multilayer covered a heterogeneous surface with a chemisorption process. The nanocomposite demonstrated as > 90% adsorption efficiency for ACG2 under a variety of conditions, with reusability tests showing retention of over 80% adsorption capacity after five regeneration cycles. This study focusses on the synthesis of an algae-derived biochar with magnetic properties, enhancing its efficiency in post-adsorption separation. The adsorption of Azocarmine G2 (ACG2), a hazardous azo dye, is addressed herein for the first time, establishing the novelty of this research within the domain. Furthermore, this innovative Fe3O4@BC adsorbent compound effectively resolves the issue of recyclability. The results highlight that the algal-based magnetic biochar nanocomposite is a viable and sustainable adsorbent, demonstrating exceptional dye adsorption capacity, simplified separation processes, and recyclability. Therefore, it is deemed appropriate for extensive applications in wastewater treatment processes.

Transition Metal‐Adsorbed Half‐Semimetal Ferromagnetic Covalent Triazine Framework with Topological Spin Structure

The covalent triazine framework (CTF‐1) has demonstrated significant potential in gas storage, catalysis, and photoelectric devices. However, its application in magnetism has rarely been investigated to date. Herein, a series of CTF‐1 by adsorbing transition metal atoms, using high‐throughput calculations, are systematically investigated. Among them, Hf‐adsorbed CTF‐1 (Hf‐CTF‐1) emerges as a promising candidate due to its exceptional structural stability and large magnetic exchange energy. Utilizing first‐principles density functional theory calculations, the geometric, electronic, and magnetic properties of Hf‐CTF‐1 are analyzed. The results reveal that Hf‐CTF‐1 is a XY‐type half‐semimetal ferromagnetic, and the Curie temperature (Tc) is predicted to be about 166 K via Monte Carlo simulations. Further, compressive strain can modulate Tc to ≈200 K, enhancing its potential for practical applications. Spin dynamics simulations suggest the presence of topological spin textures in Hf‐CTF‐1, consistent with the Berezinskii–Kosterlitz–Thouless theory. These findings position Hf‐CTF‐1 as a highly promising material for next‐generation 2D spintronic devices.

Deformation dynamics of ferrofluid drops with field-dependent local magnetisation

Achieving precise control over the dynamic manipulation of a drop using an external magnetic field may face challenges due to the intricate relationship between the induced magnetisation and the inherent magnetic properties of the drop. Here, we put forward a fundamental theory that elucidates the morphology and behaviour of a ferrofluid droplet immersed in a different, viscous fluid when subjected to a uniform external magnetic field. Unlike previous studies, we introduce an asymptotic model that investigates the dynamic evolution of the drop by examining the local magnetisation as a function of the magnetic field itself. This leads to an additional contribution to the interfacial energy, resulting in an excess normal traction at the interface. Our analytical findings highlight the significant impact of saturation magnetisation and initial susceptibility of the ferrofluid on the resulting dynamic characteristics, which are further explored through comprehensive numerical simulations to address deformations beyond the scope of the asymptotic theory. Supported by benchmark numerical and experimental results, our study suggests that higher magnetic fields and/or greater saturation magnetisation can enhance drop elongation and accelerate its settling process. We develop a regime map illustrating various dynamic events based on the magnetic properties, which could have fundamental implications for the design and control of micro-encapsulations across a wide range of applications, including thermal processing, chemical synthesis, analysis and medical diagnostics.

Magnon-Magnon Interactions Corrected Curie Temperature in Monolayer Magnets.

Understanding the temperature-dependent properties of intrinsic two-dimensional magnets is crucial for both fundamental research and technological applications. In this work, we employ nonlinear spin-wave theory, which incorporates magnon-magnon interactions, to evaluate the Curie temperature and spin-wave dispersions of several Cr- and Cu-based two-dimensional magnets. We find that the resulting Curie temperatures are generally lower than those predicted by mean-field and linear-response approaches, yet they more closely match results obtained from accurate quantum Monte Carlo and random phase approximation methods, as well as experimental data. Our approach provides a robust and efficient computational framework for evaluating the corrected Curie temperature of two-dimensional magnets.

Magnon damping and mode softening in quantum double-exchange ferromagnets.

We present a comprehensive analysis of the magnetic excitations and electronic properties of {\it fully quantum} double-exchange ferromagnets, i.e., systems where ferromagnetic ordering emerges from the competition between spin, charge, and orbital degrees of freedom, but without the canonical approximation of using classical localized spins. Specifically, we investigate spin excitations within the Kondo lattice-like model, as well as a two-orbital Hubbard Hamiltonian in proximity to the orbital-selective Mott phase. Computational analysis of the magnon dispersion, damping, and spectral weight within these models reveals unexpected phenomena, such as magnon mode softening and the anomalous decoherence of magnetic excitations as observed in earlier experimental efforts, but explained here without the use of the phononic degrees of freedom. We show that these effects are intrinsically linked to incoherent spectral features near the Fermi level, which arise due to the quantum nature of the local (on-site) triplets. This incoherent spectrum leads to a Stoner-like continuum on which spin excitations scatter, governing magnon lifetime and strongly influencing the dynamical spin structure factor. Our study explores the transition from coherent to incoherent magnon spectra by varying the electron density. Furthermore, we demonstrate that the magnitude of the localized spin mitigates decoherence by suppressing the incoherent spectral contributions near the Fermi level. We also discuss the effective $J_1$-$J_2$ spin Hamiltonian, which can accurately describe the large doping region characterized by the magnon-mode softening. Finally, we show that this behavior is also present in multiorbital models with partially filled orbitals, namely, in systems without localized spin moments, provided that the model is in a strong coupling regime. Our results potentially have far-reaching implications for understanding ferromagnetic ordering in various multi-band systems. These findings establish a previously unknown direct connection between the electronic correlations of those materials and spin excitations.

A Parametric Study of Solar Wind Properties and Composition Using Fluid and Kinetic Solar Wind Models

Abstract The physical processes in the solar corona that shape the solar wind remain an active research topic. Modeling efforts have shown that energy and plasma exchanges near the transition region play a crucial role in modulating solar wind properties. Although these regions cannot be measured in situ, plasma parameters can be inferred from coronal spectroscopy and ionization states of heavy ions, which remain unchanged as they escape the corona. We introduce a new solar wind model extending from the chromosphere to the inner heliosphere, capturing thermodynamic coupling across atmospheric layers. By including neutral and charged particle interactions, we model the transport and ionization processes of the gas through the transition region and corona and into the solar wind. Instead of explicitly modeling coronal heating, we link its spatial distribution to large-scale magnetic field properties. Our results confirm that energy deposition strongly affects wind properties through key mechanisms involving chromospheric evaporation, thermal expansion, and magnetic flux expansion. For sources near active regions, the model predicts significant solar wind acceleration, with plasma outflows comparable to those inferred from coronal spectroscopy. For winds from large coronal holes, the model reproduces the observed anticorrelation between charge state and wind speed. However, the predicted charge state ratios are overall lower than observed. Inclusion of a population of energetic electrons enhances both heavy ion charge states and solar wind acceleration, improving agreement with observations.

Magnetic Proximity Effects in Iron Germanium Telluride/Platinum Heterostructures.

Van der Waals (vdW) magnetic materials have attracted considerable attention for use in spintronic devices such as those controlled by spin-orbit torque (SOT). Such SOT-driven devices are typically fabricated by bringing a vdW magnet in proximity to a spin-charge conversion layer to achieve current-driven magnetization switching. Here, we show that such structures fabricated with iron germanium telluride (FGT) and platinum can exhibit emergent magnetic properties, which we attribute to magnetic proximity effects at the FGT/Pt interface. These changes manifest as increased perpendicular magnetic anisotropy and the emergence of additional magnetization reversal steps as probed by magneto-transport, with the most significant changes appearing in thinner flakes. The behavior was found to be robust and consistently appeared in samples made with crystals from different vendors. Our results demonstrate the potential for engineering vdW spintronic systems through magnetic proximity effects.

Synthesis of mono and hetero-bi nuclear lanthanum (III) and europium (III) complexes of 2-hydroxy-5-sulfobenzoic acid and 1,10-phenanthroline: luminescence and magnetic studies

The resurgence of interest in lanthanide coordination complexes due to their diverse applications has been increasing for past decade. These lanthanide complexes have found applications such as catalysts, sensors, optoelectronics, light sources, and modified semiconductors. The modifications in the lanthanide complex chemistry due to the use of different complexation agents enhanced the luminescence properties by varying the emission bands, stoke shifts, and lifetimes accordingly. This versatile nature of lanthanide complexes increased our interest to make a good contribution to the field. The complexes of lanthanum, europium, and novel binary complex of La and Eu metals with 1,10-phenanthroline (Phen) and 5-sulfosalicylic acid (SSA) were synthesized by co-precipitation method. Different physicochemical techniques like analytical and spectroscopic were used to characterize the ligands and complexes. The coordination of ligands with metals in complexes was confirmed by FTIR and UV spectroscopy. The surface morphology of nine coordinated La-complexes and seven coordinated Eu complexes was investigated by SEM micrographs. The X-ray crystallographic analysis revealed that all the complexes exhibit a triclinic crystal system. All the complexes were found to exhibit self-reversed magnetic hysteresis (SRMH). The luminescence and magnetic properties of mixed metal complexes are enhanced as compared to their mononuclear analogs.

Enhanced Interfacial Charge Transfer and Activation for Selective Oxidation of Benzyl Alcohol over Boron-doped Defect-Rich Fe3O4@B-CeO2/Au Photocatalyst.

Selective oxidation of aromatic alcohols to their corresponding carbonyl compounds under mild conditions holds significant promise for industrial applications. However, the performance of photocatalysts is notably hindered by limited visible-light absorption, low charge separation and transfer efficiency, as well as weak adsorption and activation of aromatic alcohols and O2. In this study, we successfully synthesized a Boron-doped defect-rich Fe3O4@B-CeO2/Au photocatalyst for the selective oxidation of benzyl alcohol (BA) to benzaldehyde (BAD) under visible light. Experimental results and density functional theory (DFT) calculations demonstrate that borondoping not only introduces a heteroatomic energy level that acts as 'intermediate springboards', significantly broadening the absorption range of visible light, but also creates abundant oxygen vacancies and acidic sites, benefiting the adsorption and activation of O2 and BA. Furthermore, the localized surface plasmon resonance (LSPR) effect of Au further improves the transport of interfacial photogenerated electrons. Due to these combined advantages, the selectivity of the Fe3O4@B-CeO2/Au photocatalyst for BAD reached 100%, and the conversion rate of BA was as high as 98.96% after 8 hours of reaction under visible light. Moreover, owing to the magnetic properties of the Fe3O4 core, the photocatalyst exhibits excellent operational and cyclic stability.

From Bimetallic Oleates to Customized Biomedical Nanoplatforms: A Versatile Approach for the Multidoping of Ferrites.

The present work represents a significant advancement in the design of magnetic nanoparticles for biomedical applications. Herein, an improved chemical approach is presented, involving the thermal decomposition of various Fe-M bimetallic oleates (where M = Mn, Co, and Zn). Through this method a series of nanoparticles (NPs) with moderate doping levels have been successfully synthesized, categorized into monodoped (MxFe3-xO4) or multidoped (MAxMByFe3-x-yO4). This advanced synthesis technique has yielded six highly monodisperse samples composed of single nanocrystals with an octahedral-like shape and with high saturation magnetization. The uniform composition of the samples has been verified using DC magnetometry, and the dopants' lattice occupation has been analyzed via 57Fe-Mössbauer spectroscopy. By modeling the AC/DC hysteresis loops, the magnetic anisotropy constants at low and room temperatures have been determined. Furthermore, the biomedical potential of the PEGylated NPs has been investigated by evaluating their magnetothermal performance, magnetic targeting capability, cytotoxicity, and antitumoral therapeutic capacity in a colon cancer-derived cell line. These findings highlight the tunable nature of the synthesized nanoplatforms, enabling precise optimization of their magnetic properties for diverse nanomedicine applications. Notably, Mn-doped nanoparticles have shown efficient heating power at 15 mT, while Mn-Co-doped counterparts have achieved exceptionally high heating at 45 mT. Additionally, the Mn-Zn nanosystem has demonstrated strong potential for both magnetic targeting and magnetic hyperthermia, further underscoring the versatility of these engineered nanomaterials.

The van der Waals antiferromagnetic proximity effect at the FePS3/Pt uncompensated interface.

van der Waals antiferromagnetic insulators are emerging as promising candidates for spintronics and quantum computing due to their unique magnetic properties. However, detecting antiferromagnetism at the atomic scale remains challenging due to compensated spin order. In this study, we present a novel approach to observe the antiferromagnetic proximity effect in FePS3/Pt heterostructures. This effect arises from interfacial magnetic moments, which induce significant spin polarization in the Pt layer via strong interlayer exchange interactions. As a result, a pronounced anomalous Hall effect is observed in the Pt layer. Fe atom vacancies at the FePS3/Pt interface play a critical role in creating localized surface magnetic moments and enhancing exchange interactions. These findings shed light on the complex interplay between two-dimensional antiferromagnetic insulators and heavy metals with strong spin-orbit coupling, providing a promising strategy to exploit interfacial effects for creating magnetization in antiferromagnetic materials.

Strain Gradient Induced Skyrmion in a van der Waals Magnet by Wrinkling.

Magnetic structures are profoundly influenced by mechanical deformation. In particular, strain has been employed to achieve the reconstruction of magnetic domains, paving a mechanical pathway to manipulate magnetic domains. However, experimentally applied strains typically exhibit non-uniform distributions. Therefore, how to distinguish the role of non-uniform strains (strain gradients) and uniform strains is crucial for understanding the mechanical manipulation of magnetic structures. Here, by directly comparing to strain tuning, it is revealed that strain gradient induced by mechanical wrinkles is critical for magnetic domain manipulation in van der Waals ferromagnet Fe3GaTe2. A ground-state labyrinthine domain transforms into a skyrmion state in the presence of an in-plane strain gradient. Additionally, an asymmetric evolutionary behavior of the magnetic domain occurs on both sides of wrinkle peaks. Theoretical simulations uncover that though opposite in-plane strain gradient hosts C2 rotational symmetry, this asymmetric domain evolution can be achieved through the coupling of perpendicular magnetic anisotropy and Dzyaloshinskii-Moriya interaction. The finding highlights the vital role of strain gradient in manipulating magnetic properties, and also offers a new mechanism for generating field-free skyrmion.

Magnetic Properties Manipulation in MnBi2Te4 through Electrochemical Organic Molecular Intercalation

Abstract MnBi2Te4, emerging as an intrinsic antiferromagnetic (AFM) topological insulator, provides a unique platform to investigate the interplay between magnetism and topology. Modulating its magnetic properties enables observation of exotic quantum phenomena like the quantum anomalous Hall effect, axion insulator states, and Majorana fermions. While Bi2Te3 intercalation can tune its magnetism, synthesizing pure-phase MnBi2Te4 with uniform Bi2Te3 intercalation remains challenging, and the fixed interlayer spacing of Bi2Te3 limits magnetic coupling tunability. Here, we utilize the electrochemical organic molecular intercalation to expand the van der Waals gap of MnBi2Te4 and modulate its magnetic properties. Through X-ray diffraction (XRD) characterizations, it is confirmed that the interlayer spacing of MnBi2Te4 is expanded from 13.6 Å to 30.5 Å and 61.0 Å by intercalating quaternary ammonium cations (THA+ and CTA+), respectively. The THA-MnBi2Te4 exhibits dual complex magnetic behavior, combining AFM ordering with Néel temperature (T N) at 12 K and a small ferromagnetic hysteresis loop at 2 K. The CTA-MnBi2Te4 shows robust ferromagnetism with curie temperature (T C) at 15 K, similar to the MnBi2Te4 monolayer. These results demonstrate remarkable changes in magnetic properties of MnBi2Te4 via electrochemical intercalation, providing new insights into manipulating magnetism in layered magnetic materials.

Investigation of the structural, electronic, magnetic, and mechanical characteristics of double half-Heusler alloys V2Ni2Z′Z′′ (Z′ = Al, Ga and Z′′ = Sb, Sn) using ab initio computational methods

The electronic, magnetic, elastic, and vibrational properties of new double half-Heusler (DHH) alloys V2Ni2Z′Z′′ are investigated within the density functional theory (DFT) calculations. All investigated alloys demonstrated mechanical, dynamic, and thermodynamic stability and complied with the Slater–Pauling rule. The analysis of their magnetic states indicates that all DHH alloys under investigation exhibit a ferromagnetic ground state. Electronic property analysis reveals that each alloy behaves as a half-metal, with an energy gap in the spin-up channel ranging from 0.103 to 0.653 eV. Based on the B/G ratio, the brittleness–ductility assessment yielded values around 2.5, indicating that alloys are ductile. The combination of magnetic properties, half-metallicity, and mechanical resilience makes these V2Ni2Z′Z′′ alloys promising candidates for high-performance spintronics devices and other advanced technological applications.

Transforming waste into value: Single-step in situ synthesis of magnetic porous carbon composite adsorbents from sugarcane bagasse and iron scrap

The demand for sustainability is driving research into new ways to make use of waste products. Porous adsorbents with magnetic properties are reusable and do not require a significant external energy source. They are well-suited to the task of decontaminating water on a large scale and, if benignly synthesized from waste products, they would meet the demand for sustainability. In this research, an in situ single-step synthesis is developed that generates a magnetic porous carbon composite from iron scrap and sugarcane bagasse, both of which are abundant waste products. This procedure combines the processes of carbonization, magnetization, and activation in one step. Iron scrap serves as both a magnetic precursor and a self-activating agent, so no additional chemical activators are required. The large surface area (505 m2/g) of the synthesized magnetic porous carbon composite adsorbent and its large capacity for tetracycline adsorption (687.6 mg/g) are suitable properties for the treatment of contaminated wastewater. The synthesis process is straightforward, and the use of waste materials to fabricate an adsorbent that retains its performance even after five cycles of adsorption and desorption ensures both cost-effectiveness and sustainability to support the concept of the circular economy.