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Half-metallic semi-Heusler compounds (also known as half-Heusler compounds) are currently at the forefront of scientific research due to their potential applications in spintronic devices. Unlike other semi-Heuslers, the p 0 (d 0) -d compounds do not appear to crystallize in the typical variant of the C 1 b structure. We investigate this phenomenon in the p 0 -d Heusler compounds LiYGa and LiYGe, where Y varies between Ca and Zn, using first-principles ab initio electronic band-structure calculations. We examine the electronic and magnetic properties of these compounds in relation to the three possible C 1 b structures. Notably, LiVGa, LiVGe, LiMnGa, and LiCrGe are half-metallic ferromagnets across all three variations of the C 1 b lattice structure. Our findings will serve as a foundation for future experimental studies on these compounds. [ABSTRACT FROM AUTHOR]

Hybrid ferromagnet–semiconductor systems possess new outstanding properties, which emerge when bringing magnetic and semiconductor materials into contact. In such structures, the long-range magnetic proximity effect couples the spin systems of the ferromagnet and semiconductor on distances exceeding the carrier wave function overlap. The effect is due to the effective p–d exchange interaction of acceptor-bound holes in the quantum well with d-electrons of the ferromagnet. This indirect interaction is established via the phononic Stark effect mediated by the chiral phonons. Here, we demonstrate that the long-range magnetic proximity effect is universal and observed in hybrid structures with diverse magnetic components and potential barriers of various thicknesses and compositions. We study hybrid structures consisting of a semimetal (magnetite Fe3O4) or dielectric (spinel NiFe2O4) ferromagnet and a CdTe quantum well separated by a nonmagnetic (Cd,Mg)Te barrier. The proximity effect is manifested in the circular polarization of the photoluminescence corresponding to the recombination of photoexcited electrons with holes bound to shallow acceptors in the quantum well induced by magnetite or spinel itself, in contrast to interface ferromagnet in case of metal-based hybrid systems. A nontrivial dynamics of the proximity effect is observed in the studied structures due to recombination-induced dynamic polarization of electrons in the quantum well. It enables the determination of the exchange constant Δexch ≈ 70 μeV in a magnetite-based structure. The universal origin of the long-range exchange interaction along with the possibility of its electrical control offers prospects for the development of low-voltage spintronic devices compatible with existing solid-state electronics. [ABSTRACT FROM AUTHOR]

To investigate the novel quantum dynamic behaviors of magnetic materials that arise from complex spin–spin interactions, it is necessary to probe the magnetic response at a speed greater than the spin-relaxation and dephasing processes. Recently developed two-dimensional (2D) terahertz magnetic resonance (THz-MR) spectroscopy techniques use the magnetic components of laser pulses, and this allows investigation of the details of the ultrafast dynamics of spin systems. For such investigations, quantum treatment—not only of the spin system itself but also of the environment surrounding the spin system—is important. In our method, based on the theory of multidimensional optical spectroscopy, we formulate nonlinear THz-MR spectra using an approach based on the numerically rigorous hierarchical equations of motion. We conduct numerical calculations of both linear (1D) and 2D THz-MR spectra for a linear chiral spin chain. The pitch and direction of chirality (clockwise or anticlockwise) are determined by the strength and sign of the Dzyaloshinskii–Moriya interaction (DMI). We show that not only the strength but also the sign of the DMI can be evaluated through the use of 2D THz-MR spectroscopic measurements, while 1D measurements allow us to determine only the strength. [ABSTRACT FROM AUTHOR]

In this Perspective, we present some important aspects of two fundamental concepts of modern spintronics, namely, spin–orbit torque and topology. Although these two fields emerged separately in condensed matter physics, in spintronics they show a deep connection, which requires further theoretical and experimental investigation. The topological features can arise both from momentum space via the wave functions as well as from real space via complex magnetic configurations. These features manifest themselves as unique aspects of different equilibrium and non-equilibrium properties. Physical interactions of such a topological origin can open new possibilities for more efficient mechanisms for manipulating magnetic order with electrical currents, which, in turn, can lead to faster and more efficient spintronics devices. [ABSTRACT FROM AUTHOR]

Spin wave computing device where an algorithm can be encoded by recording a corresponding magnetization pattern onto a hard magnetic material was previously proposed [K. Rivkin and M. Montemorra, "Spin wave computing using pre-recorded magnetization patterns," J. Appl. Phys. 132, 153902–153911 (2022)] and a particular implementation of a vector-matrix algorithm was demonstrated. In the present article, we analyze the conditions allowing for implementation of complex algorithms which can combine multiple additive, multiplicative, and conditional operators including logic expressions. Special attention is given to how the input data are provided. Rather than relying on a set of independent sources of the RF field, as is common with the existing spin wave computing methods, we demonstrate usability of more simple solutions using adjustable external quasistatic magnetic fields. We also show how, for the given setup, probabilistic switching of magnetic elements at elevated temperatures can be used to convert deterministic algorithms into a probabilistic form. [ABSTRACT FROM AUTHOR]

In this study, a CoFe 2 O 4 (CFO)/La 0.7 Ca 0.3 MnO 3 (LCMO) polycrystalline bulk was selected as representative material. Pressure (P) was applied during the magnetic measurements to tune the interparticle distance for changing exchange coupling (EC), dipolar interaction (DI), and anisotropy (K). Further, the effects of these factors on the magnetic properties of the composite magnet were investigated, and the main results are as follows. At ambient pressure, a step-like spontaneous magnetization is observed due to the difference in anisotropy between the particles. The magnetic transition temperature of LCMO in the composite is lower than that of the pure LCMO due to the lattice mismatch and the Co(Fe)–O–Mn super-exchange interaction occurring at the interface between CFO and LCMO. In the low temperature region, the pressure reduces the magnetization, due to the enhanced distortion of MnO 6 octahedra in LCMO, induced extra anisotropy and the enhanced DI by the pressure. The coercivity of the composite at 10 K increases monotonically with pressure due to the pressure-induced anisotropy, while the remanence magnetization-to-saturation magnetization ratio (M r / M s) decreases with pressure. This is attributed to (i) the reduced M r caused by the enhanced distortion of the Mn3+O 6 octahedra and the pressure-induced anisotropy, and (ii) the larger M s of the composite with respect to that of the pure CFO. Briefly, compared with the single-phase magnetic material, variation in the magnetic properties of the composite magnet with temperature, magnetic field, and pressure exhibits more complex behaviors. Moreover, several factors should be considered for the related mechanisms, such as the effects of pressure on the inter-grain EC and DI, pressure-induced anisotropy, distortion of the Mn3+O 6 octahedra in manganite, lattice mismatch, and EC at the interface. These results provide an experimental reference for understanding the mechanism that accounts for the magnetic properties observed in composite magnets, which can promote their practical applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Among magnetic materials, spinel ferrite is regarded as a potentially excellent low-frequency electromagnetic wave (2–8 GHz) absorber with low magnetic resonance frequency. However, spinel ferrite manufactured by conventional methods tends to be shape-isotropic, making the magnetic loss of the absorber quite weak under the Snoek Limit. Accordingly, our work prepares a highly shape-anisotropic Ni 0.5 Mn 0.5 Nd 0.04 Fe 1.96 O 4 ferrite (H-NMNF) with multiple crystal structures (mainly decahedral) via a novel sol-gel method. Compared with the uniformly laminated Ni 0.5 Mn 0.5 Nd 0.04 Fe 1.96 O 4 ferrite prepared by the conventional sol-gel method (C-NMNF), the natural resonance loss of H-NMNF is dramatically improved owing to the enhanced shape-anisotropic effect resulting in the Snoek Limit being breached. The results show that H-NMNF achieves the maximum effective absorption bandwidth (EAB max) of 6.64 GHz (2.96–9.6 GHz) at a thinner matching thickness of 5.1 mm, covering approximately the entire low-frequency band. This study provides methodological guidance for manufacturing magnetic loss materials with high shape-anisotropy and a new strategy for fabricating ultra-broadband, low-frequency magnetic electromagnetic wave absorbers. [ABSTRACT FROM AUTHOR]

That long-term consumption of water with arsenic concentrations greater than 10 μg L−1 induces renal, hepatic, and cardiovascular diseases, in addition, the effective adsorbents for removing arsenic are limited by their harsh synthesis conditions, slow adsorption kinetics, low adsorption capacities and hard solid-liquid separation. Herein, a hierarchical cauliflower-like γ -Fe 2 O 3 /H- γ -AlOOH magnetic composites for the treatment of As(V)-contaminated wastewater is firstly proposed to avoid the complex centrifugation and filtration process, and achieve the purpose of simplifying operation. A series of physicochemical characterization tools reveal the successful synthesis of hierarchical cauliflower-like γ -Fe 2 O 3 /H- γ -AlOOH magnetic composite adsorbent with a large specific surface area (S BET) of 131.82 m2 g 1, high Zeta potential of +17.22 mV, and magnetic saturation (Ms) of 26.1 emu g−1, which synergistically improves the adsorption performance and achieve the purpose of simplifying operation. The related adsorption experimental data demonstrates that the saturated adsorption capacity for As(V) reaches 130.17 mg g−1 and decreases by only 17.6 % after six adsorption-desorption experiments, and the whole adsorption process conforms to Pseudo-second order model and the Langmuir model, which proves it is more inclined to be monolayer adsorption and there is no chemical reaction between As(V) and adsorbent. In addition, the adsorption of As(V) onto the cauliflower-like γ -Fe 2 O 3 /H- γ -AlOOH magnetic composites is assigned to a spontaneous, endothermic and entropy increased process. The main adsorption mechanism is that, combined with X-ray photoelectron spectroscopy (XPS) analysis, all components of the composite are involved in the adsorption of As(V), with the predominance of metal hydroxyl groups. The synthetic route of a novel and highly effective adsorbent, the hierarchical cauliflower-like γ -Fe 2 O 3 /H- γ -AlOOH magnetic composite material, provides a more promising alternative candidate for the As(V) treatment, from the perspective of aquatic ecosystem protection and solid-liquid separation. The synthetic route of a novel and highly effective adsorbent, the hierarchical cauliflower-like γ -Fe 2 O 3 /H- γ -AlOOH magnetic composite material, provides a more promising alternative candidate for the As(V) treatment, from the perspective of aquatic ecosystem protection and solid-liquid separation. [Display omitted] [ABSTRACT FROM AUTHOR]

β-Gallium oxide has well-studied electrical characteristics but relatively less explored optical as well as magnetic properties. In this work, pure and Ni-doped β-Ga2O3 polycrystalline powders were prepared using a hydrothermal method to study the structural, optical, and magnetic properties at various concentrations of Ni at 1 M%, 3 M%, 5 M%, and 7 M%. XRD analysis confirmed the formation of monoclinic β-Ga2O3 up to Ni 1 M% doping. The formation of additional peaks was observed exclusively for the samples doped with Ni from 3 M% to 7 M%. These additional peaks belong to NiGa2O4 that has an inverse spinel structure. The reflectance studies using UV–Vis diffuse reflectance spectroscopy shows a reduction in bandgap from approximately 4.7 eV to 4.1 eV with the addition of the dopant. The emission peaks observed from photoluminescence studies shows UV, blue, and green emissions with varying intensity. Room-temperature magnetic studies performed using a vibrating sample magnetometer showed a transition from the diamagnetic state of the pure sample to the antiferromagnetic state with increasing Ni concentration in the doped samples. The diamagnetic properties of β-Ga2O3 makes it ineffective in spintronic applications. From the present work, the improved magnetism due to Ni doping coupled with the optical properties suggests that nickel-doped gallium oxide can be used as an optical magnetic bifunctional material. [ABSTRACT FROM AUTHOR]

The Stoner–Wohlfarth model is a classical model for magnetic hysteresis of single-domain magnets. For two-dimensional (2D) magnets at finite temperatures, the Stoner–Wohlfarth model must be extended to include intrinsic strong spin fluctuations. We predict several fundamentally different hysteresis properties between 2D and 3D magnets. The magnetization switching diagram known as the astroid figure in the conventional Stoner–Wohlfarth model becomes highly temperature dependent and asymmetric with respect to the transverse and longitudinal magnetic fields. Our results provide new insights into the spintronics applications based on 2D magnetic materials. [ABSTRACT FROM AUTHOR]

It is established that 2D magnetic materials are the ideal platform for building up modern-day electronic and spintronic devices. The popular ways to achieve 2D magnetic materials are mechanical exfoliation and chemical vapor deposition. However, the direct chemical synthesis route of such magnetic 2D materials on a large scale is relatively unexplored. This article reports an easy and cost-effective facile chemical synthesis with a proper capping agent and magnetic study of free-standing 2D Cr2S3 nanosheets and Cr2S3 nanoparticles within the temperature range of 2–300 K under the magnetic field of up to 5 T. Although few magnetic results on 2D Cr2S3 are available in the literature, there is enough scope to work for an in-depth understanding of the magnetic aspects of this 2D material. Here, ferrimagnetic ordering with a sufficiently high coercivity of up to 0.139 T at 2 K along with a tendency to the saturation in magnetization down to a certain temperature limit is observed. Contrary to the strong antiferromagnetic coupling with a Néel temperature, as observed by previous researchers, is also observed for this chemically synthesized 2D Cr2S3 nanosheets. A transition temperature of 117 K is observed for the Cr2S3 nanosheets, whereas for Cr2S3 nanoparticles, a transition temperature of 101.7 K is observed with negligible coercivity. This facile synthesis technique may be applied to achieve other non-van der Waals type 2D magnetic materials. These kinds of non-van der Waals type 2D magnets will be useful to modern-day spintronic devices. [ABSTRACT FROM AUTHOR]

The cryogenic magnetocaloric effect has attracted great attention due to its application in cryogenic refrigeration technology, which is essential for space science and quantum computing. In this study, the magnetocaloric effect of Gd2GeMoO8 (GGMO) and Dy2GeMoO8 (DGMO), which were prepared by simple solid-state reactions, had been investigated. The XRD refinement analysis suggested that GGMO and DGMO crystallize in a tetragonal structure. A large magnetic entropy change (ΔSM) of −41.2 J kg−1 K−1 was observed at 1.8 K for GGMO under a magnetic field (ΔH) of 7 T. A moderate ΔSM of −14.1 J kg−1 K−1 was obtained at 4.5 K under a ΔH of 7 T in DGMO. The refrigeration capacity and relative cooling power reached 257.4 and 337.8 J kg−1 for GGMO and 133.3 and 143.7 J kg−1 for DGMO, respectively, under a ΔH of 0–7 T. Our results suggest that GGMO is a competitive cryogenic magnetic refrigeration material. [ABSTRACT FROM AUTHOR]

In the paper, a magneto-mechanic hysteresis model for giant magnetostrictive materials is suggested by considering the effect of the domain rotation and domain wall motion on the magnetization process under prestress and the applied magnetic field. The coercive force, which is magneto-mechanic dependent, is proposed instead of a pinning constant in the Jiles–Atherton model. The model can well predict the characteristics of a magnetization-applied field curve and magnetostrictive strain-applied field curve shown in the experiment, especially the "overturn phenomenon" under different compressive prestresses. Furthermore, the effect of the microstructure parameter, such as the ratio of the domain wall thickness to the internal stress wavelength, the amplitude of internal stress, the ratio of the domain wall thickness to the inclusion radius, and inclusion consistency, on coercive force under applied prestress can also be described by the model. The comparison between the results predicted by the model and experiment shows that the model is suited for a wide-ranging applied magnetic field. [ABSTRACT FROM AUTHOR]

High spin-injection-efficiency (SIE) and thermal spin-filter-effect (SFE) from a magnetic material to a barrier material are crucial to the high performance of a spintronic device and a spin caloritronic device, respectively. By performing a nonequilibrium Green's function combined with first-principles calculations, we study the voltage-driven and temperature-driven spin transport properties of a half Heusler alloy RuCrAs based spin valve with different atom-terminated interfaces. The spin valve with a CrAs-top (or Ru-top) interface structure has an ultrahigh equilibrium magnetoresistance (MR) ratio of ∼1.56 × 109% (or ∼5.14 × 108%), ∼100% SIE, a large MR ratio, and high spin current intensity under bias voltage, suggesting that it has a great potential application in spintronic devices. The spin valve with the CrAs-top (or CrAs-bri) interface structure has a perfect SFE due to its very high spin polarization of temperature-driven currents, and it is useful in spin caloritronic devices. [ABSTRACT FROM AUTHOR]

The use of metasurfaces to engineer the response of magnetic materials is of utmost importance in the field of magnon-spintronics. Here, we demonstrate a method to fabricate one- and two-dimensional magnonic crystals with arbitrary symmetry and use it to engineer the amplitude-frequency characteristic of magnetostatic surface spin waves excited in a magnetic material. The technique is based on the gentle microablation of the sample surface by focused femtosecond laser pulses. Tightly focused illumination allows using modest pulse energy while achieving micrometer precision. By raster scanning the incident laser spot on the sample surface, we control the shape and size of the building blocks constituting the unit cell of the crystal along with its symmetry and lattice parameter. Remarkable and controlled changes in the measured transmission characteristics reveal the strong and complex symmetry-dependent interaction of the spin waves with Bravais and non-Bravais lattices. The described single-step microfabrication method facilitates and speeds up the realization of integrated spintronics components and provides an efficient tool to explore complex magnetic dynamics in scattering lattices. [ABSTRACT FROM AUTHOR]

The exchange stiffness constant is recognized as one of the fundamental properties of magnetic materials, though its accurate experimental determination remains a particular challenge. In thin films, resonance measurements exploiting perpendicular standing spin waves (PSSWs) are increasingly used to extract this parameter, typically through a determination of the first-order PSSW mode. Here, we present a systematic study of multiple PSSW modes in NiFe films, where both the sample thickness and the cap layer material are varied. The results show that a simple analysis based on the Kittel rigid pinning model yields an exchange stiffness constant that varies with thickness, mode number, and capping layer material. This finding is clearly inconsistent with physical expectation that the exchange stiffness constant of a material is single valued for a particular set of thermodynamic conditions. Using a more general exchange boundary condition, we show, through a comprehensive set of micromagnetic simulations, that a dynamic pinning mechanism originally proposed by Wigen is able to reproduce the experimental results using a single value of Aex. Our findings support the utility of short wavelength, higher order PSSWs to determine the Aex of thin films and show that the value of Aex obtained has a weak dependency on the material immediately adjacent to the magnetic layer. [ABSTRACT FROM AUTHOR]

This study describes using carbon fibers coated with magnetic material as a filler in polyethylene for EMI shielding. It investigates how to utilize barium ferrite (BaFeO3) as a conducting filler in a polyethylene matrix by optimizing the conditions for its electroless deposition onto carbon fibers. Various polymer nanocomposite samples were prepared using varying concentrations of BFO@CF. Scanning electron microscopy is used to assess the surface appearance of the composite and the distribution of BFO@CF within the polymer matrix. Including MWCNT/graphene nanoplatelets exhibit superior shielding properties, and the polymer composite with the BFO@CF demonstrates enhanced mechanical properties. The 8.2 to 12.4 GHz frequency range is used to study the EMI shielding properties. For the composition ratio of LDPE: MWCNT: GNP: BFO@CF (50 : 5 : 47.5 : 2.5), a maximum shielding of 67 dB was attained. After BFO@CF was added to the matrix, the absorption mechanism rather than the reflection mechanism dominated the shielding mechanism. A thorough evaluation and discussion of the shielding mechanism and parameters are presented. [ABSTRACT FROM AUTHOR]

In topological magnetic materials, the topology of the electronic wave function is strongly coupled to the structure of the magnetic order. In general, ferromagnetic Weyl semimetals generate a strong anomalous Hall conductivity (AHC) due to a large Berry curvature that scales with their magnetization. In contrast, a comparatively small AHC is observed in noncollinear antiferromagnets. We investigated HoAgGe, an antiferromagnetic (AFM) Kagome spin-ice compound, which crystallizes in a hexagonal ZrNiAl-type structure in which Ho atoms are arranged in a distorted Kagome lattice, forming an intermetallic Kagome spin-ice state in the ab-plane. It exhibits a large topological Hall resistivity of ~1.6 µΩ-cm at 2.0 K in a field of ~3 T owing to the noncoplanar structure. Interestingly, a total AHC of 2,800 Ω-1 is observed at ~45 K, i.e., 4 TN, which is quite unusual and goes beyond the normal expectation considering HoAgGe as an AFM Kagome spin-ice compound with a TN of ~11 K. We demonstrate further that the AHC below TN results from the nonvanishing Berry curvature generated by the formation of Weyl points under the influence of the external magnetic field, while the skew scattering led by Kagome spins dominates above the TN. These results offer a unique opportunity to study frustration in AFM Kagome lattice compounds. [ABSTRACT FROM AUTHOR]

The rapidly emerging field of 2D magnetic materials has garnered significant attention due to its fascinating physical properties and wide‐ranging potential applications. This review highlights the importance of magneto‐optical interactions as a crucial tool for both studying and modulating 2D magnets. It offers a comprehensive survey of current research concerning magneto‐optical interactions in 2D magnetic materials, encompassing the magneto‐optical Kerr effect, reflection magnetic circular dichroism, second‐harmonic generation, photoluminescence, inelastic light scattering, and time‐resolved spectroscopy. This review discusses how these techniques provide insights into the properties of 2D magnets, enabling exploration of magnetic phase transitions, lattice alterations, spin dynamics, as well as their responses to external fields. Moreover, it emphasizes the modulation of magnetic properties by photo‐stimulation and offers a brief outlook on this swiftly developing field. [ABSTRACT FROM AUTHOR]

Femtosecond laser excitation of materials exhibiting magnetic spin textures promises advanced magnetic control via the generation of non‐equilibrium spin dynamics. Ferrimagnetic [Fe(0.35 nm)/Gd(0.40 nm)]160 multilayers are used to explore this approach, as they host a rich diversity of magnetic textures from stripe domains at low magnetic fields, a dense bubble/skyrmion lattice at intermediate fields, and a single domain state for high magnetic fields. Using femtosecond magneto‐optics, distinct coherent spin wave dynamics are observed in this material in response to a weak laser excitation, enabling an unambiguous identification of the different magnetic spin textures. Moreover, employing strong laser excitation, versatile control of the coherent spin dynamics via non‐equilibrium transformation of magnetic spin textures becomes possible by both creating and annihilating bubbles/skyrmions. Micromagnetic simulations and Lorentz transmission electron microscopy with in situ optical excitation corroborate these findings. [ABSTRACT FROM AUTHOR]

We report the laser-induced voltage (LIV) signals in cubic phase Sr3YCo4O10.5+δ (CP-SYCO) thin films with a c-axis tilted and discuss the relationship between the LIV signals and magnetic anisotropy. CP-SYCO thin films were epitaxially deposited on 0°, 5°, 10°, 15°, and 20° miscut LaAlO3 (001) substrates using pulsed laser deposition (laser energy of 200 mJ, post-annealed at 760 °C). The peak voltage of the LIV for the 15° tilted CP-SYCO film is 310 mV (under laser energy of 400 mJ/pulse), with a rising edge of 26 ns. Compared with G-type antiferromagnetic ordered tetragonal phase Sr3YCo4O10.5+δ(OT-SYCO, deposited at a laser energy of 300 mJ, post-annealed at 790 °C) film, the CP-SYCO exhibits much stronger magnetization anisotropy along in-plane and out-plane due to the possible A-type antiferromagnetic moment arrangement. CP-SYCO films also demonstrate significant thermoelectric anisotropy, supporting the transverse thermoelectric effect, which is partially attributed to the contribution of spin entropy. This study provides an understanding of the anisotropic behavior in atomic layer thermoelectric stack materials and explores magnetic anisotropic material systems. [ABSTRACT FROM AUTHOR]

Surface-active magnetic materials having suitable anchoring moieties have gained great interest in the field of environmental pollution management. Herein, 3,5-diaminobenzoic acid (DABA)-functionalized Fe3O4 (Fe3O4@DABA) nanoparticles were synthesized for adsorbing anionic pollutants from wastewater. First, Fe3O4 nanoparticles were fabricated via aqueous coprecipitation of Fe3+ and Fe2+ ions, and then, the bare-surface of Fe3O4 was functionalized concomitantly with DABA. The production of Fe3O4 particles and their surface functionalization with DABA, and the thermal stability of Fe3O4@DABA were confirmed using Fourier transform infrared spectroscopy and gravimetry. Core-Fe3O4 particles had a spinel structure, and their concurrent surface functionalization did not alter the initial phase purity of Fe3O4, as revealed by an X-ray diffraction study. Fe3O4@DABA particles showed nano-sized, spherical-shaped, improved surface morphology, surface area, surface porosity, and pH-dependent surface activities. Fe3O4@DABA nanoparticles exhibited a higher hydrodynamic average diameter and better aqueous dispersity than those of bare-Fe3O4. The saturation magnetization of Fe3O4@DABA was found to be 47 emu g−1 under ambient conditions. Our designed magnetic Fe3O4@DABA nanoadsorbent showed very high affinity towards the uptake of azo dye molecules: maximum adsorption of 259 mg g−1 for Congo red (CR) and 282 mg g−1 for Eosin yellow (EY) was reached at pH 3 and 25 °C by using an adsorbent dose of 0.02 g. Adsorption isotherm and kinetic study suggested both CR and EY adsorption followed the Freundlich adsorption model and pseudo-first-order kinetics. The adsorbed azo dye was eluted effectively from the surface of the investigated nanoadsorbent by aqueous alkali (0.1 M NaOH) treatment. In addition, Fe3O4@DABA showed excellent magnetic recyclability without considerable loss of adsorption capacity. After recycling five times, the adsorption efficiency of Fe3O4@DABA slightly declined (90.16% for CR, and 95.52% for EY) compared to that of the initial adsorption. [ABSTRACT FROM AUTHOR]

This paper summarizes the results of numerous studies aimed at improving the operating characteristics of electric motors used in light electric vehicles (LEVs). This review focuses on four types of electric motors that can be installed in the drive wheel rims of LEVs. Due to the availability of new magnetic materials and the use of advanced techniques for optimizing the design of electric motors, new motor topologies have emerged. The latest generation motors have been shown to be more efficient, have higher torque density, and generate less torque ripple. This paper indicates and discusses current trends in the topology of electric motors designed for LEV drives. In this context, the effectiveness of the proposed design modifications in terms of selected motor operational characteristics was assessed. The proposed new topologies were compared with commercial solutions, also in terms of the possibility of improving their operational parameters. [ABSTRACT FROM AUTHOR]

Inkjet printing of magnetic materials has increased in recent years, as it has the potential to improve research in smart, functional materials. Magnetostriction is an inherent property of magnetic materials which allows strain or magnetic fields to be detected. This makes it very attractive for sensors in the area of structural health monitoring by detecting internal strains in carbon fibre-reinforced polymer (CFRP) composite. Inkjet printing offers design flexibility for these sensors to influence the magnetic response to the strain. This allows the sensor to be tailored to suit the location of defects in the CFRP. This research has looked into the viability of printable soft magnetic materials for structural health monitoring (SHM) of CFRP. Magnetite and nickel ink dispersions were selected to print using the JetLab 4 drop-on-demand technique. The printability of both inks was tested by selecting substrate, viscosity and solvent evaporation. Clogging was found to be an issue for both ink dispersions. Sonicating and adjusting the jetting parameters helped in distributing the nanoparticles. We found that magnetite nanoparticles were ideal as a sensor as there is more than double increase in saturation magnetisation by 49 Am2/kg and more than quadruple reduction of coercive field of 5.34 kA/m than nickel. The coil design was found to be the most sensitive to the field as a function of strain, where the gradient was around 80% higher than other sensor designs. Additive layering of 10, 20 and 30 layers of a magnetite square patch was investigated, and it was found that the 20-layered magnetite print had an improved field response to strain while maintaining excellent print resolution. SHM of CFRP was performed by inducing a strain via bending and it was found that the magnetite coil detected a change in field as the strain was applied. [ABSTRACT FROM AUTHOR]

The aim of this work is to optimize the sensor positions of a sensor–actuator measurement system for identifying local variations in the magnetic permeability of cut steel sheets. Before solving the actual identification problem, i.e., finding the material distribution, the sensor placement of the measurement setup should be improved in order to reduce the uncertainty of the identification of the material distribution. The Fisher information matrix (FIM), which allows one to quantify the amount of information that the measurements carry about the unknown parameters, is used as the main metric for the objective function of this design optimization. The forward problem is solved by the finite element method. The results show that the proposed method is able to find optimal sensor positions as well as the minimum number of sensors to achieve a desired maximum parameter uncertainty. [ABSTRACT FROM AUTHOR]

Negative thermal expansion materials can solve the challenge of mismatched coefficients of thermal expansion of components in precision instruments, thereby improving the thermal shock resistance of devices. The adjustment of negative thermal expansion performance can improve the universality of its application. In this work, tunable thermal expansion has been achieved in Hf1−xTaxFe2 kagome magnets via magnetic phase competition. The transition from ferromagnetism to antiferromagnetism results in a sharp volume shrinkage of Hf0.83Ta0.17Fe2 within a narrow temperature range of 190–230 K, which limits its practical application. As the Ta content decreases, the ferromagnetic ground state becomes more robust and eventually suppresses the antiferromagnetism completely, achieving a negative thermal expansion in Hf0.88Ta0.12Fe2 caused by the ferromagnetic to paramagnetic transition over a wide temperature region and containing room temperature (αV = −37.63 × 10−6 K−1, 250–350 K). This work realizes the regulation of negative thermal expansion through magnetic phase competition, which provides guidance for the regulation of thermal expansion of magnetic materials in the future. [ABSTRACT FROM AUTHOR]

Herbal medicine (HM) is crucial in disease management and contains complex compounds with few active pharmacological ingredients, presenting challenges in quality control of raw materials and formulations. Effective separation, identification, and analysis of active components are vital for HM efficacy. Traditional methods like liquid‐liquid extraction and solid‐phase extraction are time‐consuming and environmentally concerning, with limitations such as sorbent issues, pressure, and clogging. Magnetic solid‐phase extraction uses magnetic sorbents for targeted analyte separation and enrichment, offering rapid, pressure‐free separation. However, inorganic magnetic particles' aggregation and oxidation, as well as lack of selectivity, have led to the use of various coatings and modifications to enhance specificity and selectivity for complex herbal samples. This review delves into magnetic composites in HM pretreatment, specifically focusing on encapsulated or modified magnetic nanoparticles and materials like silica, ionic liquids, graphene family derivatives, carbon nanotubes, metal‐organic frameworks, covalent organic frameworks, and molecularly imprinted polymers. [ABSTRACT FROM AUTHOR]

As typical magnetic materials, ferrites and their composites play dominant roles in the design of high-performance electromagnetic wave (EW) absorber. Solvent thermal method is the most popular route for synthesizing ferrites, while systematical comparison research about the influence of reaction solvents of solvent thermal process on ferrite based material's EW absorption performance has rarely been carried out. Thus in this work, we adopted cotton fabric as raw material, and synthesized two kinds of zinc ferrite decorated hollow carbon cloth (CC@ZnFe 2 O 4) composites through solvent thermal reaction where deionized water and ethylene glycol was adopted as reaction solvents, respectively. After comprehensive and detailed comparison of the structures and performances of these two ferrite composites, the CC@ZnFe 2 O 4 synthesized in deionized water phase possesses an ideal optimal absorption efficiency for EW, that is the minimum reflection loss (RL min) of −46 dB, while the effective absorption bandwidth of CC@ZnFe 2 O 4 composites synthesized in ethylene glycol phase is wider (4.9 GHz). The synergistic effect of impedance matching, interface polarization, magnetic resonance, and multiple reflections co-determined the ideal EW absorption performances of these two samples. The research can not only provide new guidance for the secondary utilization of waste textiles, but also become an important reference for the preparation of ferrite based high-performance EW absorbers through solvent thermal method. [Display omitted] [ABSTRACT FROM AUTHOR]

Van der Waals (vdW) stacking is a powerful technique to achieve desired properties in condensed matter systems through layer-by-layer crystal engineering. A remarkable example is the control over the twist angle between artificially-stacked vdW crystals, enabling the realization of unconventional phenomena in moiré structures ranging from superconductivity to strongly correlated magnetism. Here, we report the appearance of unusual 120° twisted faults in vdW magnet CrI3 crystals. In exfoliated samples, we observe vertical twisted domains with a thickness below 10 nm. The size and distribution of twisted domains strongly depend on the sample preparation methods, with as-synthesized unexfoliated samples showing tenfold thicker domains than exfoliated samples. Cooling induces changes in the relative populations among different twisting domains, rather than the previously assumed structural phase transition to the rhombohedral stacking. The stacking disorder induced by sample fabrication processes may explain the unresolved thickness-dependent magnetic coupling observed in CrI3. Artificial stacking of van der Waals materials is an effective method to design and investigate emergent physical properties in condensed matter systems. Here, the authors characterize the natural twisted layer structure of CrI3, showing its dependence on the sample fabrication process and its implications for the magnetic properties of the material. [ABSTRACT FROM AUTHOR]

Magnetic materials can display many solutions to the electronic-structure problem, corresponding to different local or global minima of the energy functional. In Hartree-Fock or density-functional theory different single-determinant solutions lead to different magnetizations, ionic oxidation states, hybridizations, and inter-site magnetic couplings. The vast majority of these states can be fingerprinted through their projection on the atomic orbitals of the magnetic ions. We have devised an approach that provides an effective control over these occupation matrices, allowing us to systematically explore the landscape of the potential energy surface. We showcase the emergence of a complex zoology of self-consistent states; even more so when semi-local density-functional theory is augmented - and typically made more accurate - by Hubbard corrections. Such extensive explorations allow to robustly identify the ground state of magnetic systems, and to assess the accuracy (or not) of current functionals and approximations. [ABSTRACT FROM AUTHOR]

The current work aims to generate multifunctional MOFs by incorporating a well-known inorganic motif, a trinuclear Cu-pyrazolate [Cu3(μ3-OH)(μ-Pyz)3] (T-CuP) unit, as a node of the network. Accordingly, we report herein the synthesis and properties of five new compounds using five V-shaped dicarboxylic acids as auxiliary ligands. The structural features are consistent with the theme of grafting T-CuP units as nodal points of architectures whose chassis are primarily made of bent acids. V-shaped acids also induce a helical nature inside resulting frameworks. Beside their structural and physical features, T-CuP unit-based MOFs also vindicate our thematic approach of the trinuclear Cu-pyrazolate unit imparting specific physicochemical properties, such as magnetic, electrical, and catalytic properties, to resultant MOFs. The MOFs show excellent catalytic properties in reducing 4-nitrophenol, which could be attributed to the porous nature of the network along with the presence of metal centres with unsaturated coordination within the T-CuP unit. Furthermore, efficient photocatalytic degradation of harmful organic dyes confirms their importance for environmental remediation. The presence of a T-CuP unit and various functional groups also make some of the MOFs suitable candidates for electrical applications, which is indeed manifested in encouraging proton conductivity. Finally, the potential of current MOFs, fitted with a magnetically important trinuclear Cu-pyrazolate motif, as magnetic materials has also been thoroughly investigated. [ABSTRACT FROM AUTHOR]

2D magnetic materials hold substantial promise in information storage and neuromorphic device applications. However, achieving a 2D material with high Curie temperature (TC), environmental stability, and multi‐level magnetic states remains a challenge. This is particularly relevant for spintronic devices, which require multi‐level resistance states to enhance memory density and fulfil low power consumption and multi‐functionality. Here, the synthesis of 2D non‐layered triangular and hexagonal magnetite (Fe3O4) nanosheets are proposed with high TC and environmental stability, and demonstrate that the ultrathin triangular nanosheets show broad antiphase boundaries (bAPBs) and sharp antiphase boundaries (sAPBs), which induce multiple spin precession modes and multi‐level resistance. Conversely, the hexagonal nanosheets display slip bands with sAPBs associated with pinning effects, resulting in magnetic‐field‐driven spin texture reversal reminiscent of "0" and "1" switching signals. In support of the micromagnetic simulation, direct explanation is offer to the variation in multi‐level resistance under a microwave field, which is ascribed to the multi‐spin texture magnetization structure and the randomly distributed APBs within the material. These novel 2D magnetite nanosheets with unique spin textures and spin dynamics provide an exciting platform for constructing real multi‐level storage devices catering to emerging information storage and neuromorphic computing requirements. [ABSTRACT FROM AUTHOR]

Details on anisotropic magnon dispersion in van der Waals (vdW) ferromagnetic insulators CrPS4 and CrSBr are reported, driven by anisotropic Heisenberg exchange couplings arising from in‐plane broken crystal symmetry. The anisotropic magnon dispersion contributes to longitudinal and transverse magnon currents generating the anisotropic spin Seebeck effect (ASSE) and the thermal Hall effect (THE) accompanied with spin Nernst effect (SNE), requiring neither external magnetic field nor Berry curvature. In CrPS4, the ASSE exhibits a very large anisotropy ratio of over 100% as the thermal gradient along different main axes, and this ratio can be further tuned by temperature or a gate current. The THE and SNE unconstrained by spin‐orbit coupling (SOC) emerge when the thermal gradient is not parallel to the main axis, characterized by a large Hall angle ≈ 0.4. Compared to CrPS4, CrSBr exhibits a more limited anisotropic magnon transport owing to the less variation in magnon group velocities along different main axes. Moreover, the reversed magnitude relationship of magnon group velocities leads to the transverse magnon current being oriented in the opposite direction. These findings identify low‐symmetry vdW magnetic materials as a promising framework for generation and manipulation of anisotropic magnon transport, relevant for spincaloritronic devices in the ultrathin regime. [ABSTRACT FROM AUTHOR]

An ideal hydrogen storage material is a key topic in efficient hydrogen energy utilization. We have explored several potential hydrogen storage materials Mg 3 XH 8 (X = Ca, Sc, Ti, V, Cr, Mn) by first-principles calculations. The studied materials all belong to lightweight hydrogen storage materials. The normal phonon dispersion spectrum indicates, without regard to other materials, at least Mg 3 TiH 8 and Mg 3 VH 8 are completely stable in dynamics, which is also demonstrated by elastic stability criteria. The elastic properties show that they are all ductile materials with the applicable potential in flexible fields. Besides, they are gapless and metallic in band structures. With the correction of Hubbard values, all transition metal based Mg 3 XH 8 materials are magnetic materials with magnetic moments of 0.34 μ B for Mg 3 ScH 8 , and 2.14 μ B for Mg 3 TiH 8 , 1.29 μ B for Mg 3 TiH 8 , 2.65 μ B for Mg 3 TiH 8 and 4.86 μ B for Mg 3 MnH 8 , respectively. Whereas Mg 3 CrH 8 and Mg 3 MnH 8 exhibit highly light active in infrared and visible region. Considering overall structural stability, excellent mechanical properties, high gravimetric hydrogen density (6.21% and 6.07%) and moderate hydrogen desorption temperature (∼350 K), Mg 3 TiH 8 and Mg 3 VH 8 are considered as the candidates for promising hydrogen storage materials. Besides, Due to half-metallic nature, they are also potential in spin electronic devices. [Display omitted] • First-principles calculations to investigate Mg 3 XH 8 materials for hydrogen storage. • Mg 3 TiH 8 and Mg 3 VH 8 are found to be dynamically stable and ductile. • Mg 3 TiH 8 and Mg 3 VH 8 are half-metallic and promising in spin electronic devices. • Mg 3 TiH 8 and Mg 3 VH 8 both possess high gravimetric hydrogen density (>6.0%). • The hydrogen desorption temperatures of Mg 3 TiH 8 and Mg 3 VH 8 are around 350 K. [ABSTRACT FROM AUTHOR]

Introducing magnetism into topological insulators enables exotic phenomena such as quantum anomalous Hall effect. By fabricating van der Waals (vdW) heterostructures using layered magnetic materials, we can not only induce a gap in the non-magnetic topological surface states through magnetic proximity but also further manipulate the magnetic properties of magnetic topological insulators. However, the scarcity of 2D ferromagnetic insulator materials limits the fabrication of such heterostructures. Here, we demonstrate the vdW heterostructure devices comprising metal ferromagnetic Fe3GeTe2 nanoflakes and few-layer antiferromagnetic topological insulator MnBi2Te4 separated by an insulating hexagonal-boron nitride spacer. These devices exhibit significant exchange bias with the exchange bias field of over 100 mT under certain conditions. Our results prove that besides magnetic insulators, metallic magnets can also effectively adjust the magnetic properties of topological insulators, thereby inspiring diverse configurations of the heterostructures between topological insulators and magnetic materials. [ABSTRACT FROM AUTHOR]

Introducing magnetism into topological insulators enables exotic phenomena such as quantum anomalous Hall effect. By fabricating van der Waals (vdW) heterostructures using layered magnetic materials, we can not only induce a gap in the non-magnetic topological surface states through magnetic proximity but also further manipulate the magnetic properties of magnetic topological insulators. However, the scarcity of 2D ferromagnetic insulator materials limits the fabrication of such heterostructures. Here, we demonstrate the vdW heterostructure devices comprising metal ferromagnetic Fe3GeTe2 nanoflakes and few-layer antiferromagnetic topological insulator MnBi2Te4 separated by an insulating hexagonal-boron nitride spacer. These devices exhibit significant exchange bias with the exchange bias field of over 100 mT under certain conditions. Our results prove that besides magnetic insulators, metallic magnets can also effectively adjust the magnetic properties of topological insulators, thereby inspiring diverse configurations of the heterostructures between topological insulators and magnetic materials. [ABSTRACT FROM AUTHOR]

Magnetic metal absorbing materials have exhibited excellent absorptance performance. However, their applications are still limited in terms of light weight, low thickness and wide absorption bandwidth. To address this challenge, we design a broadband and low-profile multilayer absorber using cobalt–iron (CoFe) alloys doped with rare earth elements (REEs) lanthanum (La) and Neodymium (Nd). An improved estimation of distribution algorithm (IEDA) is employed in conjunction with a mathematical model of multilayer absorbing materials (MAMs) to optimize both the relative bandwidth with reflection loss (RL) below −10 dB and the thickness. Firstly, the absorption performance of CoFe alloys doped with La/Nd with different contents is analysed. Subsequently, IEDA is introduced based on a mathematical model to achieve an optimal MAM design that obtains a balance between absorption bandwidth and thickness. To validate the feasibility of our proposed method, a triple-layer MAM is designed and optimized to exhibit wide absorption bandwidth covering C, X, and Ku bands (6.16–12.82 GHz) and a total thickness of 2.39 mm. Then, the electromagnetic (EM) absorption mechanisms of the triple-layer MAMs are systematically investigated. Finally, the triple-layer sample is further fabricated and measured. The experimental result is in good agreement with the simulated result. This paper presents a rapid and efficient optimization method for designing MAMs, offering promising prospects in microwave applications, such as radar-stealth technology, EM shielding, and reduced EM pollution for electronic devices. [ABSTRACT FROM AUTHOR]

In this paper, the method for calculating losses in magnetic cores operating in a DC/DC power converter is experimentally verified for selected samples. The chosen method of calculating magnetic losses based on loss measurements under sinusoidal excitation is described, and the measurement process is discussed. The results of power loss measurements with a direct current bias for three different magnetic core materials, e.g., ferrite, nickel-iron-molybdenum alloy powder, and nanocrystalline, are presented. A quantitative determination of the deviations for the tested method is proposed, including the frequency dependence of the deviation distribution. [ABSTRACT FROM AUTHOR]

With the abuse of antibiotics, its pollution poses an increasing threat to the environment and human health. Effective degradation of organic pollutants in water bodies is urgent. Compared to traditional treatment methods, advanced oxidation processes that have developed rapidly in recent years are more environmentally friendly, efficient and applicable to a wider range of organic compounds. FeWO4 was used in this study as the iron-based semiconductor material to modify and optimize the material design. Fe3O4/FeWO4 composites were prepared by a two-step hydrothermal method. The crystal structure, surface morphology, electrochemical properties and separability of the composite semiconductor were analyzed by XRD, XPS, UV-vis, SEM, EDS and Mott-Schottky. The results showed that, when the initial contaminant concentration was 30 mg/L, the initial solution pH was 4, the dosage of the catalyst was 25 mg and the dosage of hydrogen peroxide was 30 μL, the degradation efficiency of tetracycline hydrochloride (TCH) could reach 91% within 60 min, which was significantly improved compared to the performance of the single semiconductors Fe3O4 and FeWO4. In addition, the catalyst prepared in this experiment can be easily recovered by magnetic separation technology in practical application, which will not affect the turbidity of water while reducing the cost of catalyst separation and recovery. [ABSTRACT FROM AUTHOR]

Ni44.1Fe33.2Ga22.8 (NFG) Heusler alloy nanowires were fabricated using a pulsed electrodeposition method. The challenge of co-depositing the Ga element in ternary alloy nanowires was addressed by employing dual complexing agents, high current, and high Ga ion concentrations. The nanowire structure was confirmed to be the B2 phase through XRD and TEM analyses. Furthermore, elemental mapping and multiple-point EDS measurements verified the homogeneous composition distribution within the nanowires. The nanowires exhibited diameters of approximately 70 nm and lengths ranging from 3 to 5 μm. The magnetic properties, including M-H and M-T dependencies, Landé g-factor, and saturation magnetization (Ms), were characterized using a vibrating sample magnetometer (VSM) and ferromagnetic resonance (FMR) techniques. No martensitic transformation was observed in the nanowires within the temperature range of 80 to 370 K. Ultimately, this work provides a fabrication strategy for the co-deposition of elements with significant potential differences in multi-component alloy electrodeposition systems. [ABSTRACT FROM AUTHOR]

The exchange bias (EB) is a unidirectional magnetic anisotropy that is found in structures containing exchange-coupled ferromagnetic/antiferromagnetic interfaces. The EB usually manifests as a horizontal shift of the hysteresis after cooling the system through the Néel temperature of the antiferromagnet in the presence of an external magnetic field. A vertical shift and an asymmetry of the magnetization loop are also possible. At present, the EB is often investigated for its effect on an application in magnetic devices in a variety of material systems and applications. The EB bilayer systems Fe/FeF2 and Fe/MnF2 represent an interesting case of structural similarities. In this paper, we show that differences between magnetic material orders and disorder contributions, found at the microscale, make them model systems for the occurrence of specific magneto-crystalline anisotropies and specific angular dependencies of the EB with significant implications for magneto-electronic applications. [ABSTRACT FROM AUTHOR]

This current study examines the magnetic behavior of a mixed CrI3 monolayer nanosystem using Monte Carlo simulations. The main objective was to examine the impact of variations in ferrimagnetic coupling parameters (JσS), external magnetic field (H) and crystal field (|D|) on the blocking temperature. The analysis reveals the emergence of a compensation temperature for |D| = 2 and 3. In addition, the hysteresis behavior analysis highlights how changes in JσS, D and T affect the magnetic behavior of the system. Decreasing JσS values show similar trends, with additional loops and magnetization plateaus attributed to negative JσS values. These results deepen our understanding of the magnetic property of CrI3 monolayer nanosystem and pave the way for applications in advanced magnetic materials and devices. [ABSTRACT FROM AUTHOR]

The adsorption of a model protein such as bovine serum albumin (BSA) on a magnetic material based on montmorillonite (MtMag) was studied. Kinetic data, equilibrium isotherms, and thermodynamic calculations were performed and analyzed to obtain information about the rate-limiting step of the adsorption process and propose a possible adsorption mechanism. Equilibrium studies showed optimal adsorption around pH 4.5, the maximum adsorption capacity being around 231.9 mg g-1 at 25 °C. The latter behavior may be ascribed to the most packed protein conformation at pH conditions near the BSA isoelectric point. In addition, the BSA adsorption capacity decreased with the ionic strength (10–3−10–1 M) and increased with the temperature (15–30 °C). In all cases, the Sips model yielded the best fit to the experimental results. The thermodynamic analysis revealed an isosteric heat dependence on the coverage, which allowed ruling out the Langmuir model. The kinetic data were adequately fitted by the IPD model, which suggests that the rate-limiting step of the adsorption process is the diffusion of BSA molecules into the internal sites. [ABSTRACT FROM AUTHOR]

We report a novel chemical methodology for the synthesis of nanocrystalline CoWN2 which is stabilized by the induction effect. The methodology involves the nitridation of sol-gel-derived CoWO4 precursor in nanocrystalline form using gaseous NH3(g). We could obtain CoWN2 as a nitrided product at both 700 °C and 750 °C with varied crystallinity. The synthesized materials were characterized using XRD, FESEM, EDS, and magnetic measurements. XRD studies confirm hexagonal CoWN2 phase formation with a minor impurity phase which comprises of metallic Co. We have noted the values of lattice constants of CoWN2 materials, i.e., a = 2.876(7) Å, b = 2.876(6) Å, c = 15.372(48) Å, and a = 2.872(3) Å, b = 2.872(2) Å, and c = 15.381(21) for the products synthesized at 700 °C and synthesized at 750 °C, respectively. The crystallite sizes are calculated as 11 ± 0.5 nm for CoWN2 nanomaterials synthesized at 700 °C whereas 16 ± 0.5 nm for CoWN2 nanomaterials synthesized at 750 °C. FESEM micrograph studies of CoWN2 nanomaterials show nearly spherical particles. The average particle sizes obtained from FESEM images are 90 ± 5 nm for the nanomaterials obtained at 700 °C and 45 ± 2 nm for those obtained at 750 °C. Room temperature magnetic parameters, i.e., Ms and Hc for CoWN2 materials synthesized at 700 °C are found to be 1.49 emu/g and 389 Oe, respectively, whereas for CoWN2 materials (synthesized at 750 °C), the values marginally reduce to 0.06 emu/g and 375 Oe, respectively. [ABSTRACT FROM AUTHOR]

We present our findings on the room temperature (RT) soft ferromagnetism (FM) of the sol-gel-prepared Co-doped barium titanate (BaTiO3) nanoparticles with two distinct Co concentrations (0.25 mol% and 0.5 mol%), that is appropriate for spintronic applications as evidenced by experimental observations. X-ray diffraction investigation revealed that the produced samples, which had diameters less than 100 nm, belonged to the pseudo-cubic phase of the BaTiO3 structure and did not exhibit any signs of the Co cluster or any other Co oxides. UV-visible absorption spectra demonstrate that the optical response is red shifted and the bandgap energy is lowered when Co is incorporated into the BaTiO3 lattice. The inclusion of cobalt ions may have brought about a change in size or an increase in surface defects, as evidenced by the PL spectra, which show that the intensity of emission peaks changes as the dopant concentration increases. In the 0.25 mol% Co-doped BaTiO3 sample, the FM behavior is clearly visible along with the paramagnetic (PM) phase at RT. Significantly, it becomes apparent that as the doping concentration is raised to 0.5 mol%, the saturation magnetization is reduced, and a pure phase of soft FM is obtained. This soft FM feature witnessed in 0.5 mol% doped BaTiO3 with low coercivity (96.8 Oe) and low saturation magnetization (9.7 × 10−3 emu/g) is likely due to oxygen vacancies and could set out as a promising magnetic material for possible spintronic applications. [ABSTRACT FROM AUTHOR]