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Magnetometers have received considerable attention in recent years. Magnetic components offer an alternative methodology to improve the sensitivity. Due to their exceedingly small structural dimensions, metasurfaces exhibit significant competitiveness in field modulation. A magnetic field concentration phenomenon of spheres at the nanoscale is presented in this paper. The sensitivity of a magnetometer is, therefore, improved through the enhanced static or quasistatic magnetic field by the nanosphere concentrator. Magnetic field redistribution due to the assistance of nanospheres is discussed in this paper using the finite element method. The numerical method is verified with classical analytical equations with a single sphere. The simulation results show that the magnetic field concentrates in the near field behind the nanosphere along the direction of the magnetic flux density. The radius, material or permeability exactly, and distribution are critical parameters to the concentration strength. The magnetic gain of a single nanosphere with typical positive permeability of the typical soft magnetic material reaches 3, and thus, the field along the magnetic flux direction concentrates. Furthermore, the amplification factor is more prominent with the nanosphere arrays compared to a single sphere with the same scale of size, and amplification improves with the sphere numbers and distributions in the array arrangement, which provides a novel approach for the designing of the magnetic flux concentrator being monolithically integrated with the magnetometer probe. Our simulation results provide a new degree of freedom by using nanoscale structures to manipulate magnetic fields. [ABSTRACT FROM AUTHOR]

The complex permeability and power losses are very important parameters for soft magnetic materials. In this paper, the temperature dependence of these two parameters is investigated for Mn–Zn ferrite. The Hopkinson peak was observed at 440 K below the Curie temperature (TC), and the domain-wall resonance peaks and the natural resonance peaks gradually move to lower frequencies until the Hopkinson temperature (TH). Further, the domain-wall resonance peaks from relaxation type to resonance type are observed by fitting the permeability spectrum, which is related to the reduction of the loss factor. In addition, the power losses were measured from 245 to 365 K and divided into hysteresis loss (Ph), eddy current loss (Pe), and excess loss (Pexc). Each loss contribution was discussed to be dependent on temperature. The results show that at high temperatures and high frequencies, the thermal superposition effect will cause an abnormal increase in excess loss. [ABSTRACT FROM AUTHOR]

Solid solution modulation is an ideal method for combining the advantages of different parent compounds while mitigating their disadvantages. Here, we investigated the thermal sensitivity, magnetic properties, and microwave absorption of MgxMn1−xAl2xFe2(1−x)O4 (0.2 ≤ x ≤ 0.8) spinel solid solution ceramics for application in multifunctional devices. The electrical transport and magnetic properties can be modulated by adjusting the solution ratio. The ceramics exhibit negative temperature coefficient characteristic. The B‐values from 5065–8056 K, suggesting accurate temperature measurements over a wide temperature range. As a type of soft magnetic material, it has a narrow hysteresis loop and high resistivity. Vector network analyzer studies indicate Mg0.2Mn0.8Al0.4Fe1.6O4 could be a candidate for microwave absorption in S‐band. This study successfully extends the applicability of MgxMn1−xAl2xFe2(1−x)O4 ceramics for high‐temperature thermistors and also confirms potential for multifunctional device. [ABSTRACT FROM AUTHOR]

This study presents the synthesis and comprehensive analysis of polycrystalline Li x Ni 0.6 Zn 0.4-2 x Fe 2+ x O 4 (with x values of 0.00, 0.01, 0.03, 0.05, 0.07, 0.09) ferrites, with lithium (Li) concentrations ranging from x = 0.00 to 0.09, utilizing the sol-gel auto-combustion method followed by sintering at 800 °C for 8 h. A nuanced examination of the lattice constants obtained from the X-ray diffraction patterns revealed a slight decrement from 8.386 to 8.357 Å, exhibiting a linear pattern across the Li concentration spectrum. The crystallite sizes, as determined by the Scherrer formula, fluctuated between 31 and 40 nm, while Field Emission Scanning Electron Microscopy indicated an increase in average grain size from 146 to 186 nm due to nanoparticle agglomeration. High-Resolution Transmission Electron Microscopy analysis of nanoparticles yielded an average grain size of ∼69 nm and an interplanar spacing of approximately 0.1521 nm. Magnetic characterization revealed a decrease in saturation magnetization from 87 to 70 emu/g with increasing Li content, with the lowest Ms observed for the x = 0.09 sample, indicating the material's soft magnetic nature. Raman and Fourier-transform infrared spectroscopy confirmed the retention of the conventional spinel structure, characterized by both tetrahedral and octahedral iron coordination, and illuminated the impact of co-existing iron phases on the structural anomalies observed. These findings contribute valuable insights into the effects of lithium substitution on the structural, morphological, and magnetic properties of Ni-Zn ferrites, underscoring their potential for various technological applications. [ABSTRACT FROM AUTHOR]

The magnetoelastic effect is known as the dependence between the magnetic properties of the material and applied mechanical stress. The stress might not be applied directly but rather generated by the applied torque. This creates the possibility of developing a torque-sensing device based on the magnetoelastic effect. In this paper, the concept of an axially twisted toroidal magnetic core as a torque-sensing element is considered. Most known works in this field consider the utilization of an amorphous ribbon as the core material. However, Ni-Zn ferrites, exhibiting relatively high magnetostriction, also seem to be promising materials for magnetoelastic torque sensors. This paper introduces a theoretical description of the magnetoelastic effect under torque operation on the basis of total free energy analysis. The methodology of torque application to the toroidal core, utilized previously for coiled cores of amorphous ribbons, was successfully adapted for the bulk ferrite core. For the first time, the influence of torque on the magnetic properties of Ni-Zn ferrite was investigated in a wide range of magnetizing fields. The obtained magnetoelastic characteristics allowed the specification of the magnetoelastic torque sensitivity of the material and the determination of the optimal amplitude of the magnetizing field to maximize this parameter. High sensitivity, in comparison with previously studied amorphous alloys, and monotonic magnetoelastic characteristics indicate that the investigated Ni-Zn ferrite can be utilized in magnetoelastic torque sensors. As such, it can be used in torque-sensing applications required in mechanical engineering or civil engineering, like the evaluation of structural elements exposed to torsion. [ABSTRACT FROM AUTHOR]

Corrosion of soft magnetic materials during service can significantly impact their performance and service life, therefore it is important to improve their corrosion resistance. In this paper, the corrosion resistance, alternating current soft magnetic properties (AC SMPs) and microstructure of FeCoNixAl (x = 1.0–2.0) medium-entropy alloys (MEAs) were studied. Corrosion resistance is greatly improved with an increase in Ni content. The x = 2.0 alloy has the lowest corrosion current density (Icorr = 2.67 × 10−7 A/cm2), which is reduced by 71% compared to the x = 1.0 alloy. Increasing the Ni content can improve the AC SMPs of the alloy. When x = 1.75, the total loss (Ps) is improved by 6% compared to the x = 1.0 alloy. X-ray diffraction (XRD) and scanning electron microscopy (SEM) show that the increase in Ni content is beneficial for promoting the formation of the face-centered-cubic (FCC) phase, and the body-centered-cubic (BCC) phase is gradually divided by the FCC phase. Electron backscatter diffraction (EBSD) shows that, with the increase in Ni content, the number of grain boundaries in the alloy is greatly reduced and numerous phase boundaries appear in the alloys. The degree of strain concentration is significantly reduced with the increasing Ni content. The corrosion mechanism of alloys is also discussed in this paper. Our study provides a method to balance the soft magnetic properties and corrosion resistance, paving the way for potential applications of Fe-Co-Ni-Al MEAs in corrosive environments. [ABSTRACT FROM AUTHOR]

The design, modeling, fabrication, and characterization of three types of printed circuit board (PCB)-integrated solenoid inductors using air core and two embedded magnetic cores are demonstrated in this paper. The fabrication applies a double-side PCB process to form the inductor windings. A cavity for accommodating the magnetic cores is created in the middle of the PCB. Two types of magnetic cores fabricated using in-house developed proprietary processes are applied as magnetic cores for the inductors. One of these cores is made out of FeSiAl magnetic powder, while the other is made out of laminated NiFe thin films. The size of the inductor is 5 mm × 3 mm × 1.56 mm. The quality factor of the FeSiAl powder core inductor reaches its peak value of 36.6 at 40 MHz. The NiFe multilayer thin-film core inductor obtains the highest inductance (22.48 nH) at 10 MHz but has a lower quality factor compared with the two other inductors. The tested saturation current of both magnetic core inductors is greater than 3 A. The inductors are also tested in a Buck converter switching at 10 MHz with an input voltage of 4 V, output voltage of 1 V, and load current of 1 A. The FeSiAl powder core inductor has the lowest loss of 115 mW, thereby suggesting that embedding the pre-made powder cores or multilayer thin-film cores is a good option for manufacturing PCB-integrated inductors. The powder core approach tends to yield an excellent high frequency performance, while the multilayer thin-film core option allows the integration of the magnetic thin-film process into the PCB fabrication flow to reduce costs and improve reliability for volume production. [ABSTRACT FROM AUTHOR]

Design and development of novel high entropy alloys (HEAs) having balance magnetic properties with other functional properties are vital for industrial applications of these alloys. In this study, a novel Co35Cr5Fe10Ni30Ti5Al15 HEA was synthesized through mechanical alloying and studied for phase evolution and its effects on magnetic properties with annealing at different temperatures. As-synthesized HEA has a major fcc phase with minor concentrations of bcc and R phases. The as-synthesized HEA is also annealed at different temperatures of 500, 700 and 900°C and found that the phase identity of formed phases maintained after annealing. However, for HEA annealed at 1000°C, slight amount of new σ-phase has formed along with initial phases. Values of Ms and Hc were found to be 75 emu g−1 and 18 Oe for as-synthesized Co35Cr5Fe10Ni30Ti5Al15 HEA. We found that after annealing at different temperatures, magnetic properties of Co35Cr5Fe10Ni30Ti5Al15 HEA show significant improvement. Co35Cr5Fe10Ni30Ti5Al15 HEA annealed at 900°C exhibited good soft magnetic characteristics with high Ms (99 emu g−1), low values of Hc (3.8 Oe) and Mr (0.45 emu g−1), as compared to other samples developed in the present study. Thus, designed and developed 900°C annealed Co35Cr5Fe10Ni30Ti5Al15 HEA can be further used for magnetic switching applications due to the high value of Ms and low value of Mr. [ABSTRACT FROM AUTHOR]

Composite materials are materials composed of two or more components that have different physical and chemical properties. These properties complement each other to create a material with unique properties that cannot be achieved by using the individual components alone. Modelling the effect of preparation processes on the properties of composite materials is an important tool to predict the properties of a material prior to its manufacture. This can help in optimizing the preparation technology and obtaining the desired material properties. In the present work the topicality of the problem of iron-based composite materials and the possibilities of modelling and simulation of selected models are presented. [ABSTRACT FROM AUTHOR]

This study investigates the effects of multi-transition metals on the soft magnetic properties of Fe73.5−xB9Si14Cu1Nb2.5Mx (M = Nb, Mo, and W) nanocrystalline soft magnetic alloys. Nanocrystalline soft magnetic materials are utilized in electronic components on the basis of their permeability and low core loss. In conventional alloys such as FINEMET, Nb inhibits nanocrystal growth and promotes amorphous formation. In this research, Mo and W were used as additional transition metals to control the size of nanocrystals and explore the potential for enhancing soft magnetic properties. We confirmed that the addition of Mo and W reduced the nanocrystal size, and the activation energy for nanocrystal formation and growth showed significant benefits for nanocrystalline alloys. Consequently, the soft magnetic properties of the alloys containing Mo and W exhibited higher permeability and lower coercivity. These results suggest that multi-transition metals are effective in improving soft magnetic properties by inhibiting nanocrystal formation and growth. [ABSTRACT FROM AUTHOR]

Soft magnetic materials (SMMs) are indispensable for electromechanical energy conversion in high-efficiency applications, but they are exposed to increasing mechanical loading conditions in electric motors due to higher rotational speeds. Enhancing the yield strength of SMMs is essential to prevent the degradation in magnetic performance and failure from plastic deformation, yet most SMMs have yield strengths far below one gigapascal. Here, we present a multicomponent nanostructuring strategy that doubles the yield strength of SMMs while maintaining ductility. We introduce morphologically anisotropic nanoprecipitates through dislocation-driven precipitation induced by preceding deformation during heat treatment in an iron–nickel–cobalt–tantalum material. With all dimensions of the precipitates below the magnetic domain wall width, we achieve a high precipitate number density with a large specific surface area, small interprecipitate spacing, and high lattice mismatch, which impede dislocation glide and strengthen the material. Both the matrix and precipitates are ferromagnetic, yielding a high magnetic moment. This nanostructuring approach offers a pathway to two-gigapascal-strong ductile SMMs with moderately increased coercivity that can be tolerated in exchange for significantly improved mechanical performance for sustainable electrification. Designing soft magnets with yield strengths exceeding one gigapascal while remaining ductile to prevent irreversible deformation for safe and efficient operation is challenging. The authors address this challenge by employing a nanostructuring strategy with morphologically anisotropic precipitates. [ABSTRACT FROM AUTHOR]

Energy loss in shielding soft magnetic materials at low frequencies (1–100 Hz) can cause fluctuations in the material's magnetic field, and the resulting magnetic noise can interfere with the measurement accuracy and basic precision physics of biomagnetic signals. This places higher demands on the credibility and accuracy of loss separation predictions. The current statistical loss theory (STL) method tends to ignore the high impact of the excitation dependence of quasi-static loss in the low-frequency band on the prediction accuracy. STL simultaneously fits and predicts multiple unknown quantities, causing its results to occasionally fall into the value boundary, and the credibility is low in the low-frequency band and with less data. This paper proposes a progressive loss decomposition (PLD) method. Through multi-step progressive predictions, the hysteresis loss simulation coefficients are first determined. The experimental data of the test ring verifies the credibility of PLD's prediction of the two hysteresis coefficients, improving the inapplicability of the STL method. In addition, we use the proposed method to obtain the prediction results of the low-frequency characteristics of the loss of a variety of typical soft magnetic materials, providing a reference for analyzing the loss characteristics of materials. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) shows promise as a method for producing soft-magnetic multicomponent alloys for use in electric motors and sustainable electromobility applications. However, the simultaneous achievement of a high saturation magnetic flux density (Bs) and a low coercivity (Hc) in AM soft-magnetic materials remains challenging. Herein, we present an approach that integrates an elemental powder mixture of Fe45Co30Ni25 with Fe2O3 nano-oxides, which is then subjected to laser powder bed fusion (LPBF) followed by high-temperature annealing to achieve an FCC-structured Fe45Co30Ni25 MEA/FeO composite. The FeO nanoparticles, a byproduct of the reaction between Fe powders and Fe2O3 nano-oxides, serve as nucleation sites for the formation of a single FCC phase in the MEA matrix. The resulting LPBF MEA/FeO composite has a Bs of 2.05 T and an exceedingly low Hc of 115 A m−1, compared to those of the BCC/FCC dual phase MEA and other state-of-the-art additively manufactured soft-magnetic alloys. In situ Lorentz transmission electron microscope (TEM) revealed that the low Hc of the FCC-structured MEA/FeO composite originates from the reduced pinning effect of grain boundaries in the FCC phase on domain wall movement compared with those in the FCC/BCC dual phase. Soft magnetic materials are critical components in the electric transport and energy sectors, such that even minor improvements in their properties can yield vast savings in energy. Here, Cao, Zhang and coauthors demonstrate via an additive manufacturing based approach, a medium entropy alloy with superior magnetic properties. [ABSTRACT FROM AUTHOR]

This paper proposes a generalized equivalent magnetic circuit model (EMCM) considering end-effect for a moving-coil electromagnetic linear actuator (MCELA). The model describes the magnetic networks in detail by incorporating the independent variable parallel branch number and constructing them as a function of variable branch number and geometric dimensions. An iterating method to update accurate relative permeability of the soft magnetic material under different working point is also taken into consideration. The comparison study of flux density and thrust force using FEM and EMCM demonstrates the effectiveness and computation efficiency of the proposed model. Additionally, a typical MCELA prototype is implemented to further validate the proposed EMCM. The proposed method can be used for the analysis and design of a wide range of electromagnetic actuators, in addition to its application to MCELA. [ABSTRACT FROM AUTHOR]

The new type of Fe83 − xSi2.5B12P2.5Cx (x = 0, 0.5, 1.0, 1.5, 2.0 at%) amorphous soft magnetic system with low cost, high saturation magnetization and low coercivity were designed and prepared by means of rapid quenching. The effect of C on the amorphous formability, thermal stability, and soft magnetic properties in the alloy system were studied. Results suggest that the addition of small atom C can promote the formation of densely atomic structure of alloy, thereby promoted the enhancement of amorphous formability. With the increase of C content, the temperature interval between two crystallization peaks increases first and then decreases. When C content is 1.0 at%, ΔT (Tx2-Tx1) reaches the maximum value, of about 109.9 ℃, which is beneficial to enhance the thermal stability and soft magnetic properties. As the concentration of C is raised, the Bs exhibit a pattern of increases followed by a subsequent decrease, while coercivity changes in the opposite way. When the C content is 1.0 at%, the Bs of the alloy reaches the highest value of 1.78 T and the coercivity exhibits the best which is 14.055 A/m. The results offer important contributions to the design and advancement of high Bs amorphous soft magnetic materials for industrial applications involving amorphous electric motors. [ABSTRACT FROM AUTHOR]

Magnetic materials always arouse interest due to their unique properties. Both soft and hard magnetic materials are exploited for energy harvesting application, magnetic recording and in MEMS. To boost the applicability of these materials, more versatile fabrication techniques must be developed. Even though the rare earth permanent magnets produced through powder metallurgy can guarantee the highest magnetic performance, this fabrication technique is not practical for the MEMS industry. Moreover, rare earths are very expensive elements. Electrodeposition seems a preferable alternative to chemical or physical vapour deposition techniques to produce both thin and thick magnetic deposits based on transition metal alloys. Among electrodeposition techniques, reverse pulse plating (RPP) guarantees improved mechanical properties and has been found to be beneficial for reducing internal stresses and modifying the internal microstructure and surface morphology as well as for producing thicker layers without observing cracks. Part 1 of the review focuses on how RPP can be used to tailor mechanical properties and morphology to achieve miniaturisation compared to other techniques, particularly in application fields that can benefit from it, such as the microelectronics industry. RPP also modifies magnetic properties by inducing changes in the microstructure. In Part 2 of this review, the state-of-the-art of hard and soft magnetic alloys deposited through RPP will be discussed, examining how this technique can tailor the crystalline structure to influence the coercivity of soft magnetic materials and the magnetic anisotropy of hard magnetic materials. [ABSTRACT FROM AUTHOR]

Magnetic field generators are a key component of Magnetic Particle Imaging (MPI) systems, and their power consumption is a major obstacle on the path to human‐sized scanners. Despite their importance, a focused discussion of these generators is rare, and a comprehensive description of the design process is currently lacking. This work presents a methodology for the design and optimization of selection field generators operating with soft magnetic materials outside the linear regime in the context of MPI. Key elements are a mathematical model of magnetic field generators, a formalism for defining field sequences, and a relationship between power consumption and field sequence. These are used to define the design space of a field generator given its system requirements and constraints. The design process is then formulated as an optimization problem. Subsequently, this methodology is then utilized to design a new magnetic field generator specifically for cerebral imaging studies. The optimization result outperforms our existing MPI field generator in terms of power consumption and field of view size, providing a proof‐of‐concept for the entire methodology. As the approach is very general, it can be extended beyond the MPI context to other areas such as magnetic manipulation of medical devices and micro‐robotics. [ABSTRACT FROM AUTHOR]

Soft magnetic materials are a core element of power electronics and electrical machines. However, none of the soft magnetic materials is able to exploit the full potential of wide bandgap semiconductors, which operate above MHz frequency for efficient energy conversion in power electronic systems. Here, a high‐performance Fe–Si soft magnetic composites with a 2D ordered domain structure are reported, enabling efficient energy conversion at MHz frequencies. By transforming spherical particles into flakes and arranging them in layers, 2D magnetic domains are created within the composite. This leads to a 90% increase in permeability and a tenfold decrease in loss at 3 MHz compared to composite made with spherical particles. The significantly increased cut‐off frequency indicates that the ordered flaky particles are suitable for MHz applications, unlike the disordered spherical particles. These findings provide an effective approach for fabricating high performance soft magnetic composites from traditional spherical particles and miniaturizing magnetic devices for efficient power electronics operation. [ABSTRACT FROM AUTHOR]

We are entering an era of re-electrification, seeking high-power density electrical machines with minimal resource use. Significant performance gains in electrical machines have been achieved through precise manufacturing processes, including the shaping/cutting of soft magnetic materials. However, most studies have evaluated magnetic performance at a macro level, focusing on components, while the fundamental mechanisms, e.g., how the micromagnetic behaviour is affected by mechanical interference, remain unclear. In this study, we examine the impact of sub-micron deformations at opposing strain rates (10−2 to 101 s−1) on the micromagnetic behaviour of soft magnetic non-oriented electrical steel. Using a diamond probe to indent within a single grain of polycrystalline material at different velocities, we induce quasi-static and dynamic mechanical loading. Our analysis, employing magnetic force microscopy, transmission Kikuchi diffraction, and scanning transmission electron microscopy with a pixelated detector, reveals that magnetic texture disturbances rely on the time-dependent dislocation dynamics of the Fe-BCC material. Additionally, we compress micro-pillars to further investigate these effects under bulk-isolated deformation. These findings highlight the importance of considering even ultra-small loads, such as nano-indentations and micro-pillar compressions, in the manufacturing of next-generation electric machines, as they can affect magnetic texture and performance. Mechanical deformations affect magnetic properties of electrical steels, impacting machine efficiency. Here, authors demonstrate that sub-micron deformations at different strain rates alter micromagnetic behaviour of non-oriented electrical steel due to time-dependent dislocation dynamics. [ABSTRACT FROM AUTHOR]

With the rise of eco-friendly policies, advanced motor technologies are being developed to replace fossil fuel-based engines in the mobility industry. Axial flux motors, known for their ability to reduce size and increase output torque compared to radial flux motors, require different materials and manufacturing techniques. Specifically, the production of complex stator cores and segmented magnets presents significant challenges, often leading to higher costs. To address this issue, soft magnetic composite (SMC) materials, which offer greater design flexibility, are being explored for use in stator cores. However, soft magnetic composite materials exhibit lower permeability and saturation flux density compared to laminated silicon steel, resulting in reduced output torque and efficiency. This paper investigates the effects of stator geometry on axial flux motor performance and explores cladding core technology, which combines soft magnetic composite materials with silicon steel. By conducting finite element method (FEM) analysis to evaluate the output torque and efficiency based on the shape of the silicon steel within the cladding core, this study proposes an optimized cladding core design to enhance the efficiency and output torque of axial flux motors. [ABSTRACT FROM AUTHOR]

A preprocessing technique named "spiral annealing" was applied for the first time to magnetic microwires. In this process, the sample was arranged in a flat spiral shape during annealing, and subsequent measurements were conducted on the unbent sample with the induced stress distribution along and transverse to the sample. The research utilized both magnetic and magneto-optical methods. The anisotropy field magnitude in both the volume and surface of the microwire was measured, and for the first time, a direct correlation between the anisotropy field and the curvature of a spirally annealed microwire was established. Additionally, a connection between the type of surface domain structure and the degree of spiral curvature was identified. The preservation of the distribution of spiral annealing-induced magnetic properties both along and across the microwire is a key effect influencing the technological application of the microwire. The range of induced curvature within which a specific helical magnetic structure can exist was also determined. This insight links the conditions of spiral annealing to the selection of microwires as active elements in magnetic sensors. [ABSTRACT FROM AUTHOR]

The advanced soft magnetic material Fe-Co-Si ternary alloy has become a research hotspot in recent years due to its excellent balanced magnetic properties. When used in an environment where oceans and magnetic fields interact, the corrosion behavior of this alloy is currently not well understood. In this study, immersion experiments and electrochemical tests have been used to explore its corrosion behavior under conditions of no magnetic field, a uniform parallel magnetic field, and a vertical magnetic field with a magnetic field. The results indicate that the presence of a magnetic field accelerates corrosion while suppressing pitting and intergranular corrosion of the alloy. Moreover, compared to the perpendicular magnetic field, the impact is more pronounced when applying a parallel magnetic field due to the synergistic effect of Lorentz force and magnetic field gradient force. Additionally, the presence of Si elements affects the formation of Co oxide passivation film, which reduced the corrosion resistance of the alloy under both magnetic and non-magnetic field conditions. This finding contributes to filling the theoretical gap in the corrosion failure behavior of Fe-Co-Si alloy under magnetic field conditions. [ABSTRACT FROM AUTHOR]

This study explores the application of AncorLam HR (Höganäs, Sweden), a soft magnetic composite material, in the stator core of an axial flux permanent magnet drive motor. Building on previous research that provided mechanical and thermal properties of the material, the focus is on analyzing how the manufacturing process affects the motor core's shape. A bulk prototype was created based on case 3, which demonstrated the least deviation in density and internal stress. The prototypes were produced under the conditions of SPM 7 and 90 °C, and a heat treatment in a nitrogen atmosphere for 1 h, resulting in an average density error of 0.54%, confirming process effectiveness. A microstructural analysis using scanning electron microscopy (SEM) on Sample 2, with the highest density, confirmed consistency between simulation and prototype trends. Electron backscatter diffraction (EBSD) and X-ray diffraction (XRD) analyses revealed that the internal phase structure remained unchanged. Energy-dispersive spectroscopy (EDS) and transmission electron microscopy (TEM) identified the elimination of phosphorus (P) during molding, affecting the insulating layer, a critical factor for SMC materials. In motor simulations and actual measurements, the average torque was recorded as 37.7 N·m and 34.7 N·m at 1500 rpm and 27.7 N·m and 25.1 N·m at 2000 rpm, respectively. The torque comparison observed in the actual measurements compared to the simulation results indicates that the output loss increases in the actual measurements due to the deterioration of the insulation performance judged based on the microstructure evaluation. This study confirms the viability of using AncorLam HR in motor cores for electric vehicles and provides key data for improving the performance. [ABSTRACT FROM AUTHOR]

Reducing the saturation magnetostriction is an effective way to improve the performance of soft magnetic materials and reduce core losses in present and future applications. The magnetostrictive properties of binary Fe-based alloys are investigated for a broad variety of alloying elements. Although several studies on the influence of Cu-alloying on the magnetic properties of Fe are reported, few studies have focused on the effect on its magnetostrictive behavior. High pressure torsion deformation is a promising fabrication route to produce metastable, single-phase Fe-Cu alloys. In this study, the influence of Cu-content and the chosen deformation parameters on the microstructural and phase evolution in the Fe-Cu system is investigated by scanning electron microscopy and synchrotron X-ray diffraction. Magnetic properties and magnetostrictive behavior are measured as well. While a reduction in the saturation magnetostriction λs is present for all Cu-contents, two trends are noticeable. λs decreases linearly with decreasing Fe-content in Fe-Cu nanocomposites, which is accompanied by an increasing coercivity. In contrast, both the saturation magnetostriction as well as the coercivity strongly decrease in metastable, single-phase Fe-Cu alloys after HPT-deformation. [ABSTRACT FROM AUTHOR]

In this paper, we explore the benefits of using a magnetostrictive component in a variable reluctance energy harvester. The intrinsic magnetic field bias and the possibility to utilize magnetic force to achieve pre-stress leads to a synergetic combination between this type of energy harvester and magnetostriction. The proposed energy harvester system, to evaluate the concept, consists of a magnetostrictive cantilever beam with a cubic magnet as proof mass. Galfenol, Fe81.6Ga18.4, is used to implement magnetostriction. Variable reluctance is achieved by fixing the beam parallel to an iron core, with some margin to create an air gap between the tip magnet and core. The mechanical forces of the beam and the magnetic forces lead to a displaced equilibrium position of the beam and thus a pre-stress. Two configurations of the energy harvester were evaluated and compared. The initial configuration uses a simple beam of aluminum substrate and a layer of galfenol with an additional magnet fixing the beam to the core. The modified design reduces the magnetic field bias in the galfenol by replacing approximately half of the length of galfenol with aluminum and adds a layer of soft magnetic material above the galfenol to further reduce the magnetic field bias. The initial system was found to magnetically saturate the galfenol at equilibrium. This provided the opportunity to compare two equivalent systems, with and without a significant magnetostrictive effect on the output voltage. The resonance frequency tuning capability, from modifying the initial distance of the air gap, is shown to be maintained for the modified configuration (140 Hz/mm), while achieving RMS open-circuit coil voltages larger by a factor of two (2.4 V compared to 1.1 V). For a theoretically optimal load, the RMS power was simulated to be 5.1 mW. Given the size of the energy harvester (18.5 cm3) and the excitation acceleration (0.5 g), this results in a performance metric of 1.1 mW/cm3g2. [ABSTRACT FROM AUTHOR]

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Magnetic materials with zero hysteresis are posed to have a significant impact on sustainable energy conversion, electronics, and communication technologies. As the global market for soft magnetic materials continues to expand, driven by increasing demand in renewable energy, automotive, and power transmission sectors, it is important to design magnets that can be cycled under an external field reversibly and rapidly multiple times without a decay in magnetic response. However, designing magnets with small hysteresis has been a challenge because we do not fully understand its origins. In this article, I outline key research efforts investigating the fundamental mechanisms underpinning hysteresis in soft magnets and, highlight recent developments in the use of nonlinear analysis and nucleation barrier methods to predict coercivity in these materials. [ABSTRACT FROM AUTHOR]

Soft magnetic composites (SMCs) are key materials in electronic devices. Conventional SMCs incorporate too much insulating material in order to reduce eddy current loss at high frequency, resulting in severe magnetic dilution and demagnetization field, which leads to deterioration of the magnetic performance. In this paper, ZnO precursor is homogeneously deployed on the surface of FeSiAl, which in situ generates a thin and dense Al2O3 layer on the surface of FeSiAl through the interfacial solid phase reaction between Al and O atoms during annealing process. Meanwhile, ferromagnetic ZnO layer is simultaneously obtained due to the loss of O. The formed Al2O3/ZnO layers effectively reduce power loss and endow high frequency stability with less influence on effective permeability. Finally, FeSiAl/ZnO‐0.4% SMC exhibits low power loss of 83.2 mW cm−3 (50 mT/100 kHz), high effective permeability of 92, and cut‐off frequency as high as 40 MHz. This study provides an efficient route for high performance SMCs and broadens high frequency application of soft magnetic devices. [ABSTRACT FROM AUTHOR]

The article introduces a novel roasting technique under a dynamic magnetic field (RDMF) that enables the rapid synthesis of MnB crystals, producing bulk and powder forms within seconds.

A class of transformable materials is introduced with magnetic defect‐defined switchable configurations. The soft material can be magnetically‐programmed to transform into various encoded patterns utilizing the rich interplay of magnetic interactions and instability phenomenon. The strategy allows us to break the limit of admissible configurations of the instability‐induced patterns that dictate the post‐transformation behavior. The phenomenon is experimentally realized in a material system consisting of periodically distributed magnetic inclusions in a soft matrix. The programmable magnetic interactions between the inclusions act as smart defects redirecting the material transformations to targeted geometric configurations. Moreover, the role of magnetic spacing and field strength is systematically investigated to map the transition between mechanically‐dominant and magnetics‐dominant instability patterns. Lastly, the idea of reconfigurable material design is showcased by embedding binary information in magnetic form, which can be read out through the unique repositioning of inclusions via the applied mechanical deformation. [ABSTRACT FROM AUTHOR]

Coatings play a crucial role in minimizing eddy current loss in soft magnetic composites (SMCs). The powder atomic layer deposition (PALD) technique was utilized to coat Fe–Ni–Mo soft magnetic powder in this study. The Al 2 O 3 coating fabricated via PALD enhanced corrosion resistance and reduced core loss in SMCs. Additional deposition cycles increased the resistivity of the Fe–Ni–Mo powder and the corrosion resistance of the Fe–Ni–Mo SMCs, indicating that the density and integrity of the amorphous Al 2 O 3 coating were enhanced. Thinner coatings (20 cycles) exhibited anodic passivation in corrosion, which was attributed to insufficient density. Nevertheless, an excessively thick coating (100 cycles) resulted in a decrease in effective permeability and an increase in hysteresis loss. The fabricated Fe–Ni–Mo SMCs (50 cycles) demonstrated a core loss of 603.1 mW/cm3 at 100 kHz/100 mT, coupled with an effective permeability of 108.5 and a Q value of 97.8 at 100 kHz. [ABSTRACT FROM AUTHOR]

Nowadays, there is a global search for electromagnetic gadgets that are affordable, eco-friendly, and energyefficient. This motivates engineers and scientists to develop new materials or enhance those that already exist. Fe-based soft magnetic materials are a significant class of soft magnetic materials that are essential to many energy-related industrial applications, including motors, converters, and electric transformers. This article focuses on the general characterization of magnetic materials, their magnetic properties and the analysis of the influence of mechanical milling of Fe powders prepared by mechanical milling in two different sizes (sample 1 - smaller then < 400 µm and sample 2 greater than > 400 µm). The experimentally obtained hysterical curves of ground Fe powders are measured using the Vibratimg Sample Magnetometer (VSM). [ABSTRACT FROM AUTHOR]

The Co-based nanocomposite alloys exhibit promising magnetic properties suitable for high-temperature applications. However, their metastable microstructure, especially the intergranular amorphous phase, raises concerns regarding their stability in elevated temperature conditions. In this study, we investigated the case of the Co75.4Fe2.3Mn2.3Si2Nb4B14 alloy. Initially, we measured activation energies under non-isothermal annealing conditions using both the Kissinger and Ozawa methods, and then further measured local activation energies by the Ozawa method. The thermal stability of the amorphous phase below the secondary crystallization temperature was explored using isothermal DSC tests, and represented using a time-temperature-transformation (TTT) diagram. Subsequently, we conducted experimental examinations to explore the microstructure evolution and air oxidation behavior at 500°C for up to 20 days. During the 20-day annealing process, abnormal grain growth of secondary crystallization was observed, leading to a deterioration in the soft magnetic properties of the material. In the 20-day oxidized sample, we found that larger crystalline grains were concentrated at the center, while the surface retained nanosized crystalline grains embedded in the residual amorphous phase. This stabilized surface area offers excellent corrosion resistance in the long-term exposure of the nanocrystalline Co75.4Fe2.3Mn2.3Si2Nb4B14 alloy. [ABSTRACT FROM AUTHOR]

An Ni25Co20Cu10Fe25Mn20 high-entropy alloy (HEA) was produced using mechanical alloying. Similar to equiatomic NiCoCuFeMn alloy, a face-centered cubic single-phase nanocrystalline HEA was obtained after 28-h milling. The lattice parameter of this new HEA (0.360 nm) was slightly smaller than that of equiatomic alloy (0.361 nm). The crystallite size of the final product was ~ 9 nm, significantly finer than the values reported for the equiatomic HEAs. According to the analysis of the HEA powder particles' deformation behavior, the system operated in a ductile-brittle mode. The thermal behavior of prepared alloy, characterized by differential thermal analysis, was similar from that of equiatomic NiCoCuFeMn alloy. Similar to the equiatomic NiCoCuFeMn, the sluggish diffusion effect was not true for the Ni25Co20Cu10Fe25Mn20 HEA. Studying the magnetic behavior of Ni25Co20Cu10Fe25Mn20 HEA, using vibrating sample magnetometry, confirmed a soft magnetic behavior for this material like an equiatomic alloy. [ABSTRACT FROM AUTHOR]

The MAX phase is a layered ternary carbide and nitride with unique properties, in which doping with transition metals can be utilized to give it new properties using alloying while ensuring its intrinsic structure. In this study, the magnetic solid solution MAX phases V2(MnxSn1-x)C, V2(FexSn1-x)C and V2(MnxFexSn1-2x)C were synthesized by pressureless sintering in V2SnC doped with Mn and Fe atoms and pressureless sintering for 3 h at 1000 °C. The maximum saturation was reached when the total doping amount was 0.4, while purity of the product decreased with the addition of solid solution elements. SEM-EDS results showed that the doping did not change the original lamellar morphology. The magnetic test results show that V2(MnxSn1-x)C(A = Mn/Fe) is a typical low-temperature ferromagnetic material. V2(MnxSn1-x)C has a wide hysteresis loop and is a typical hard magnetic material with a coercivity of 1428 Oe, while V2(FexSn1-x)C shows lower coercive properties and is a soft magnetic material, and does not show ferromagnetism at x=0.2 and x=0.4, and the Curie temperature at x=0.6 is only 42 K. The magnetization curve of V2(MnxFexSn1-2x)C shows a transition from ferromagnetism to paramagnetism at a Curie temperature of 61 K, and the hysteresis loop shows that it has a ferromagnetic property. The magnetization curve of V2(MnxFexSn1-2x)C shows a transition from ferromagnetism to paramagnetism at a Curie temperature of 61 K. The hysteresis line shows that it has the properties of a soft magnetic material and the magnetic saturation strength reaches 3.80 emu⋅g-1. [ABSTRACT FROM AUTHOR]

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Dexterity micromanipulation is a significant topic in the field of robotics. Herein, a novel robotic rotating microjoint controlled by an exogenous magnetic field based on magnetic programmable soft materials, which brings more dexterity to the micromanipulation task is proposed. First, the magnetic soft material is synthesized and the microjoint is manufactured. The maximum rotation angle and response time are characterized. Then the force analysis of the microjoint in a uniform magnetic field is performed and the relationship between the deformation bending angle of a microjoint and the magnetic field magnitude is first proposed. A sliding mode controller based on the deformation mechanism of microjoints and radial basis function neural network (DMRSMC) is proposed to achieve robust deformation control of the microjoint. The experiment that depicts the microjoint is able to achieve a maximum rotation angle of 22.16° and a response time of 16 ms. The DMRSMC controller performs angle control with higher accuracy than conventional SMC and PID controllers. Finally, a dexterous suction mechanism is developed by combining the microjoint with a soft micropipette needle to achieve dexterous grasping of zebrafish embryos with a 97% success rate and an orientation adjustment error is 1.36°. [ABSTRACT FROM AUTHOR]

Nickel-doped manganese–magnesium ferrite (NixMn0.25-xMg0.75Fe2O4) was prepared using the auto-combustion method. X-ray diffraction patterns showed a single ferrite spinel phase in all the prepared samples. The crystallite size ranged from 24.30 to 28.32 nm, increasing with increasing the Ni content. The porous structure of all the samples was verified with a scanning electron microscope. FESEM images were used to confirm the production of spherical or semi-spherical nanoparticles with little change in particle size distribution. The study revealed that the nanoparticles were small enough to behave superparamagnetically. According to the magnetic tests conducted with the VSM at room temperature, the hysteresis loop region is practically non-existent, indicating typical soft magnetic materials. In addition, the conductance responses of the magnesium ferrite nanocomposite were measured by exposing it to the oxidizing gas (NO2) at different operating temperatures. The results showed that the sensor with the nano ferrite sample of (x = 0.20) has a good sensitivity of 707.22% as well as response and recovery times. [ABSTRACT FROM AUTHOR]

The detection of magnetic nanoparticles in a liquid medium and the quantification of their concentration have the potential to improve the efficiency of several relevant applications in different fields, including medicine, environmental remediation, and mechanical engineering. To this end, sensors based on the magneto-impedance effect have attracted much attention due to their high sensitivity to the stray magnetic field generated by magnetic nanoparticles, their simple fabrication process, and their relatively low cost. To improve the sensitivity of these sensors, a multidisciplinary approach is required to study a wide range of soft magnetic materials as sensing elements and to customize the magnetic properties of nanoparticles. The combination of magneto-impedance sensors with ad hoc microfluidic systems favors the design of integrated portable devices with high specificity towards magnetic ferrofluids, allowing the use of very small sample volumes and making measurements faster and more reliable. In this work, a magneto-impedance sensor based on an amorphous Fe73.5Nb3Cu1Si13.5B9 wire as the sensing element is integrated into a customized millifluidic chip. The sensor detects the presence of magnetic nanoparticles in the ferrofluid and distinguishes the different stray fields generated by single-domain superparamagnetic iron oxide nanoparticles or magnetically blocked Co-ferrite nanoparticles. [ABSTRACT FROM AUTHOR]