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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]

Accurately calculating the losses of ferromagnetic materials is crucial for optimizing the design and ensuring the safe operation of electrical equipment such as motors and power transformers. Commonly used loss calculation models include the Bertotti empirical formula and hysteresis models. In this paper, a new hybrid hysteresis model method is proposed to calculate losses—namely, the combination of the Jiles–Atherton hysteresis model (J–A) and the Fourier hysteresis model. The traditional Jiles–Atherton hysteresis model is mainly suitable for fitting the saturation hysteresis loop, but the fitting error is relatively large for internal minor hysteresis loops. In contrast, the Fourier hysteresis model is suitable for fitting the minor hysteresis loops because the corresponding magnetic induction strength or magnetic field is lower and the waveform distortion is small. Moreover, Fourier series expansion can be expressed with fewer terms, which is convenient for parameter fitting. Through examples, the results show that the hybrid hysteresis model can take advantage of the strengths of each model, not only reducing computational complexity, but also ensuring high fitting accuracy and loss calculation accuracy. [ABSTRACT FROM AUTHOR]

Additive manufacturing of soft magnetic materials is a promising technology for creating topologically optimized electrical machines. High-performance electrical machines can be made from high-silicon-content FeSi alloys. Fe-6.5wt%Si material has exceptional magnetic properties; however, manufacturing this steel with the classical cold rolling methodology is not possible due to the brittleness of this material. Laser powder bed fusion technology (L-PBF) offers a solution to this problem. Finding the optimal printing parameters is a challenging task. Nevertheless, it is crucial to resolve the brittleness of the created materials so they can be used in commercial applications. The temperature dependence of magnetic hysteresis properties of Fe-6.5wt%Si materials is presented in this paper. The magnetic hysteresis properties were examined from 20 °C to 120 °C. The hysteresis measurements were made by a precision current generator–based hysteresis measurement tool, which uses fast Fourier transformation–based filtering techniques to increase the accuracy of the measurements. The details of the applied scalar hysteresis sensor and the measurement uncertainties were discussed first in the paper; then, three characteristic points of the static hysteresis curve of the ten L-PBF-manufactured identical toroidal cores were investigated and compared at different temperatures. These measurements show that, despite the volumetric ratio of the porosities being below 0.5%, the mean crack length in the samples is not significant for the examined samples. These small defects can cause a significant 5% decrement in some characteristic values of the examined hysteresis curve. [ABSTRACT FROM AUTHOR]

In this study, we provide the synthesis and analysis of the structure, microstructure, and spectroscopic properties of V‐doped SrTiO3. The monophasic samples were made using the usual ceramic method, which involved calcination at temperatures of 1000°C and 1300°C. The X‐ray diffraction analysis, combined with the Rietveld refinement, conclusively demonstrates that they have crystallized in a cubic structure, namely under the space group Pm3¯m$Pm\bar{3}m$. The inclusion of vanadium (V) at the titanium (Ti) site has been investigated by evaluating the size of the crystallite and grain. The investigation of dielectric and dissipation factors at different frequencies indicates the existence of interfacial and orientational polarization. Two distinct conduction and relaxation processes were identified within the temperature range examined based on the spectroscopic plot. The presence of a paramagnetic phase in the samples, caused by the presence of V and its magnetic interaction with oxygen vacancies, indicates that it can be classified as a soft magnetic material. The electrode's consistent dielectric constant and dissipation factor make it well‐suited for use in supercapacitor dielectric capacitors. Additionally, its mixed‐type conduction, involving both ionic and electronic conduction, makes it excellent for use as electrode materials in intermediate‐temperature solid oxide fuel cells' applications. [ABSTRACT FROM AUTHOR]

Permalloy (Py) films are commonly regarded as soft magnetic materials, wherein the magnetization aligns within the film plane. Our studies reveal the presence of perpendicular magnetic anisotropy in Py thin films deposited on the collinear antiferromagnetic RuO2(101) surface. By employing both the magneto-optical Kerr effect and the anomalous Hall effect, we identified the interfacial origin of the observed perpendicular anisotropy, quantifying it with an interfacial anisotropy energy of approximately 0.77 erg/cm2. Current-induced magnetization switching in Py/RuO2(101) has been achieved under an in-plane field, with the current applied along both [010] and [10 1 ¯ ] directions. Py films exhibiting perpendicular magnetic anisotropy offer an innovative material platform for investigating the spin–orbit effect, holding significant potential for spintronics applications. [ABSTRACT FROM AUTHOR]

The spinel ferrites (SFs) are renowned for their distinctive magnetic and electrical characteristics. Sol-gel route was used for the fabrication of Sr0.6 Zn0.4 Gdx Fe2-x O4 (0.00, 0.025, 0.050, 0.075, 0.100) ferrites. The structural, magnetic, microwave, and DC (direct current) properties of prepared Nps were found using of number characterization techniques. The X-ray diffraction (XRD) pattern of Sr0.6 Zn0.4 Gdx Fe2-x O4 SFs showed a single cubic phase. The magnetic behavior was determined by applying a field of 2 kOe. The various magnetic features, including those determined based on the M-H loop, and prepared spinel ferrites showed the soft nature of magnetic materials. When amount of gadolinium (Gd) is increased, then saturation magnetization, coercivity, remanence magnetization is decreased. The Ms values decreased from 69.36 to 32.18 emu/g, coercivity reduced from 220 to 14 emu/g, and remanence magnetization is decreased from 32 to 3 emu/g. The electrical parameters revealed that direct current resistivity and activation energy (Ea) increased (from 0.16 eV to 0.28eV) with the inclusion of the Gd. The activation energy was increased from 0.16 to 0.28 eV. The dielectric constant and loss of permittivity and permeability were determined by applying the frequency 5.5–9.5 GHz. From the above enhanced parameters, it can be concluded that fabricated SFs may be suitable for high-frequency devices. [ABSTRACT FROM AUTHOR]

Permanent magnets based on ferrites are currently studied as possible alternatives, in several application areas, to rare-earth-based magnets to overcome the barriers of high costs, unavailability, and environmental impact. Their attractiveness lies in the large crystalline anisotropy, ensuring resistance to demagnetization, and the possibility of having their modest saturation magnetization enhanced through exchange-coupling with a compatible soft magnetic material of higher saturation magnetization. Using analytical calculations, a micromagnetic finite element model, and comparison with measurements on a produced sample, the conditions that give the highest possible maximum energy product are determined for ferrite-based exchange-coupled Zn0.2Fe2.8O4/SrFe12O19 soft/hard nanocomposite magnets. Two geometries are considered: a spherical core–shell geometry and a composite granular microstructure. Two sets of material parameters are considered for the granular structure, one from the literature and one obtained by fitting to the measured magnetization data. The results show that it is important to have a well-aligned easy axis of hard grains and that the optimal amount of the soft material depends on the alignment of the hard grains as well as their size, with smaller grains yielding larger (BH)max values. The core–shell model shows that the maximum (BH)max can be strongly enhanced, from ∼40 to ∼60 kJ/m3, by using a hard core diameter of <30 nm and a soft shell thickness of <7 nm. The composite granular structure yields a maximum (BH)max of ∼50 kJ/m3 for a soft volume fraction of 43%. [ABSTRACT FROM AUTHOR]

In the face of the rapid development of the motor industry, some motors with traditional soft magnetic materials can no longer meet the needs of the market. Using new high-saturation magnetic density materials has become a new breakthrough to improve the torque density of motors. Fe-Co alloys (1J22) have high-saturation magnetic induction strength, which can effectively improve the motor's magnetic field strength and increase its torque density. At the same time, the temperature rise of the motor is also an important factor to consider in the motor design process. In particular, the change in core temperature caused by loss makes the coupling of the internal temperature field and the electromagnetic field of the motor more common. Therefore, it is necessary to test the temperature and magnetic properties of 1J22 together. In this paper, a coupling measurement device for magnetic properties of soft magnetic materials is built, and a 1J22 temperature field–electromagnetic field coupling experiment is completed. It is found that the maximum loss of 1J22 decreases by 4.44% with the increase in temperature; the maximum loss is 6.41% less than that of traditional silicon steel. Finally, a finite element simulation model is built to simulate the actual working conditions of the motor, and it is verified that the magnetic properties of the material at high temperature will have a certain impact on the performance of the motor. [ABSTRACT FROM AUTHOR]

Dual-phase composite magnetic materials have magnetic and permanent magnetic properties. They can realize the dual-phase conversion of soft magnetic and permanent magnetic composites with a small amount of excitation energy. They have the advantages of good control and conversion characteristics and save energy, and they have a wide range of application scenarios in regard to power equipment. In this paper, the magnetization modeling of dual-phase composite magnetic materials is carried out based on micromagnetic theory, and a specific mathematical expression is given. Secondly, the preparation process of the dual-phase composite magnetic material is studied, the dual-phase composite magnetic material is prepared, and the demagnetization curve of the dual-phase composite magnetic material is measured. Finally, the application of dual-phase composite magnetic materials in power equipment is carried out. Using the soft magnetic and permanent magnetic characteristics of dual-phase composite magnetic materials, their impact on DC bias suppression in transformers is assessed. Magnetic circuit reluctance theory is used to develop the structure and electromagnetic design of a transformer. A transformer prototype with DC bias suppression ability based on dual-phase composite magnetic materials is manufactured, and simulation and experimental research are carried out. The simulation and experimental results verify the correctness of the proposed scheme. Although this scheme requires a more complex core structure, the energy-saving effect is remarkable without changing the transformer's neutral grounding. The indicators meet the actual requirements of the project. [ABSTRACT FROM AUTHOR]

Laminated, powder filled, and dense bulk soft magnets are currently used for various electrical and electronic applications due to their characteristic magnetic properties. In order to systematically investigate the correlation between the structural features and the resulting magnetic performance of various soft magnetic materials, toroidal Fe93.5Si6.5 (wt.%) specimens with "layer structure", "powder structure", and "dense structure" are additively manufactured and characterized by means of electron beam powder bed fusion (PBF‐EB). The specimens with "layer structure" show outstanding magnetic performance in terms of low power losses and good maximum magnetic flux density at frequencies ranging from 50 to 1000 Hz, outperforming even some soft magnetic materials fabricated using conventional methods. Fe93.5Si6.5 (wt.%) specimens with various layered structures are produced using different processing strategies, allowing for sophisticated structural tailoring, and modifying the corresponding magnetic performance. Based on the results derived in this study, an ideal structure that can result in superior soft magnetic properties is proposed. [ABSTRACT FROM AUTHOR]

This study proposed an improved analytical method for electromagnetic field analysis of a wound rotor synchronous machine (WRSM) considering the permeability of soft magnetic materials. A simplified analytical model considering the magnetic permeability of each region is presented. The governing equations of each region are derived from Maxwell's equations and the electromagnetic field theory, and a general solution is derived by using mathematical techniques. The analytical solutions of all domains are derived by calculating the boundary conditions. To validate the proposed analytical method, the radial and circumferential magnetic flux densities are compared with finite element analysis (FEA) results. In addition, electromagnetic performance parameters such as flux linkage, back-electromotive force, and torque are determined using electromagnetic theories. In particular, the magnetic saturation of the soft magnetic material is due to field and armature current, and the superiority of the proposed method is demonstrated by comparing the improved analytical method considering the global saturation of each region with the nonlinear FEA result considering local saturation. The proposed analytical method can be widely used in the initial and optimal design of WRSM because it can consider saturation of the core due to changes in field and armature current. [ABSTRACT FROM AUTHOR]

Permanent magnets remain the primary source of magnetic field in magnetic refrigerators and thermomagnetic motors, generally being evaluated by the Λ cool parameter, which is applicable to a magnetic field source used in a magnetic refrigeration system. The main objective of this work is to perform a parametric and comparative analysis of a C-shaped and double C-shaped permanent magnet based on a common parameter to any arrangement of magnets, namely the figure of merit M ∗ . The analysis was conducted through computational modeling and simulation with COMSOL Multiphysics® software. Different soft magnetic materials were used in the simulations and the best-performing material was used in the magnetic circuit of the C-shaped permanent magnet to evaluate the magnetic force acting on a set of gadolinium plates. It was observed that the soft magnetic material has a significant impact on M ∗ . No significant impact on M ∗ was observed regarding to the number of gaps as long as more magnetized blocks are employed in the arrangement. Consequently, a greater gap accompanied by a lower magnetic flux density has the potential to result in an increased magnetostatic force density. [ABSTRACT FROM AUTHOR]

An approach was proposed to control the displacement of domain walls in magnetic microwires, which are employed in magnetic sensors. The velocity of the domain wall can be altered by the interaction of two magnetic microwires of distinct types. Thorough investigations were conducted utilizing fluxmetric, Sixtus–Tonks, and magneto-optical techniques. The magneto-optical examinations revealed transformation in the surface structure of the domain wall and facilitated the determination of the mechanism of external influence on the movement of domain walls in magnetic microwires. [ABSTRACT FROM AUTHOR]

In our previous work [Chen et al., Int. J. Solids Struct. 246–247, 111607 (2022)], we designed a flat arch structure for hard magnetic soft material. It used snap-through instability for remote actuation and large deformation in a small magnetic field range (25–170 Oe). The ratio of the magnetic-driven deflection to the arch length was about 0.05. To improve this ratio, we designed a high arch of magneto elastomers, which expanded the range of ratio from 0.05 to 0.5, increasing it by an order of magnitude. However, raising the arch height extended the driving range while unintentionally increasing the critical magnetic field for snap-through. To overcome this challenge, we reduced the bending stiffness of the arch-shaped structure, effectively lowering the critical magnetic field. Our goal is to optimize the structure of hard magnetic soft materials to achieve a broader driving range under quasi-static applied magnetic field conditions. This is accomplished by adjusting the arch height and structural stiffness to balance different performance requirements. Our research could have a significant impact on applications and devices that utilize magnetic materials. [ABSTRACT FROM AUTHOR]

The performance requirements of motors are gradually increasing, and anisotropic soft magnetic materials have been applied in motors to improve performance, The magnetostriction of anisotropic soft magnetic materials is one of the main contributors in extensive research on anisotropic soft magnetic material transformers. Compared to transformers, the magnetic field in motors has more complex harmonic and multi-directional characteristics. In this paper, the magnetic field of motors stator teeth under both no-load and load conditions is calculated and analyzed to research magnetostriction of anisotropic soft magnetic materials in motor magnetic field and predict the NVH performance of anisotropic soft magnetic material motors accurately. Furthermore, the magnetostriction in different magnetization angles is investigated for the multi-directional characteristics, and the result is explained from microscopic principles. This paper focuses on a splicing oriented silicon steel (OSS) motor, the magnetization angle of OSS in motor varying from 0° to 90°. Firstly, the equivalent formulas of magnetic field are obtained under the analytical and finite element calculations. After that, the frequency and direction of experiment magnetic field are confirmed and the magnetostriction of OSS in different magnetization angle and frequency is measured. In the end, the variation character of magnetostriction of OSS is summarized. [ABSTRACT FROM AUTHOR]

An effect of Cu-doped Ni-Zn nanoferrite particles synthesized through the citrate gel auto-combustion method on structural dielectric and magnetic properties was investigated. The structural characterization of synthesized powder is investigated using XRD (X-ray diffraction), FE-SEM (field emission scanning electron microscopy), EDXS (energy-dispersive X-ray spectroscopy), AFM (atomic force microscope), and TEM (transmission electron microscope). All prepared samples were established to have a single-phase spinel structure and fine grain size with an Fd-3 m space group. The lattice parameter, volume, and crystallite size decrease with increasing copper substitution. By adding copper ions, the surface area rises from 123.9 to 187.4 m2 g−1. The surface roughness is increased by AFM examination from 7.6 to 11 nm. From the AFM samples, it is shown that they are soft to hard in nature due to the Cu doping. The real imaginary impedance and the complex electric modulus were studied within the frequency range of 20 Hz to 1 kHz at room temperature, respectively. In the Cole–Cole plots studied for dielectric constant, it was observed that all samples had single semi-circles and continuously decreased with increasing copper content. This shows that the prepared material is good for high-resistance applications and the fabrication of multilayer inductor chips. The magnetic characteristics of hysteresis loops were studied at room temperature using a VSM (vibration sample magnetometer) for nanoferrites. The prepared ferrites samples were examined; copper doping increased the width of the loops, which confirms the change from soft to hard magnetic material. They are utilized in data processing, telecommunications, and the automobile industries. At low temperatures, the prepared samples showed superparamagnetic behavior. It is used in medical and electrical device applications. [ABSTRACT FROM AUTHOR]

This paper deals with the electromagnetic characterization of a laminated toroidal ferromagnetic core made through additive manufacturing, specifically using the laser powder bed fusion process. The continuing demand for increasingly efficient, lightweight, and higher performance electric machines is creating huge challenges in the design and realization of new electric motor solutions. The constant improvements in additive manufacturing technologies have prompted researchers to investigate the possibility of adopting these production techniques for the manufacture of high-value electric motors. For these reasons, this paper investigates the ferromagnetic characteristics of an additively manufactured core made with FeSi6.5 powder. The BH curve and the specific iron losses of the processed material have been measured so that they can be compared with a commercial lamination, and have the possibility of carrying out more precise finite element simulations. [ABSTRACT FROM AUTHOR]

Improvement of magnetic properties of electrical steel can be achieved by reduction the size of magnetic domains. The application of local stresses through laser scribing leads to reduced core losses. In order to determine the effect of laser refinement conditions of magnetic domains on the properties of the soft magnetic material, four samples with a thickness 0.23 mm were refined. The refinement of each sample was carried out using different line energies of the laser beam. Estimation of the magnetic domain size was performed using the Jeffries method, the magnetic viewer was used to reveal the domain structure. The measurement of the magnetic properties was performed at a frequency of 50 Hz and an induction of 1.5 T. The analyzed results presented in this work indicate impact of laser refining on magnetic properties of grain oriented electrical steel depending on used laser beam energy. [ABSTRACT FROM AUTHOR]

The paper presents the results of research from the analysis of primary magnetization curves for Fe based amorphous alloys. Structural defects in the form of pseudodislocation dipoles occur in amorphous alloys. Using the theory developed by H. Kronmuller called the approach to ferromagnetic saturation, it is possible to indirectly observe internal stresses occurring in the volume of amorphous alloys. The magnetic structure is sensitive to all kinds of inhomogeneities that become visible in the process of high-field magnetization. It has been shown that the cooling rate of the liquid alloy has a great influence on the migration of atoms during the solidification process. Longer time of alloy formation causes more atoms to occupy ordered positions, which results in a change in the distance between the magnetic atoms and a higher degree of structure relaxation. This is indicated by a significant difference in the value of the spin wave stiffness parameter Dspf. The structural differences of the alloys were also investigated using a magnetic balance. It has been shown that the cooling rate influences insignificant differences in the course of thermomagnetic curves and the Curie temperature. [ABSTRACT FROM AUTHOR]

This study was conducted to synthesize magnetic wood through the ex situ impregnation method of magnetite nanoparticles and analyze its physical properties and characterization. The process was initiated with the synthesis of magnetite nanoparticles by the co-precipitation method and the nano-magnetite was successfully synthesized with a particle distribution of 17–233 nm at an average size of 75 nm. Furthermore, the impregnation solution consisted of three different levels of magnetite nanoparticles dispersed in furfuryl alcohol, untreated and furfurylated wood for comparison. Sengon wood (Falcataria moluccana Miq.) was also used due to its low physical properties. The impregnation process was conducted by immersing the samples in the solution at a vacuum of −0.5 bar for 30 min, followed by a pressure of 1 bar for 2 h. There was also an improvement in the physical properties, such as weight percent gain, bulking effect, anti-swelling efficiency and density, while the water uptake continued to decrease. Additionally, magnetite nanoparticles appeared in wood microstructure image, supported by the result of ferrum content in chemical element analysis. The results showed that chemical change analysis proved the presence of Fe–O functional group cross-linked with wood polymer. The diffractogram also reported the appearance of magnetite nanoparticles peak and a decrease in crystallinity due to an increase in the concentration. Based on the analysis, sengon wood was classified as a superparamagnetic material with soft magnetic characteristics and the optimum treatment was furfurylated-magnetite 12.5% wood. [ABSTRACT FROM AUTHOR]

We have examined the dynamic hysteresis characteristics and phase transition behavior of permalloy nanodisk with three different shapes, which are controlled by a metric order parameter, using the OOMMF micromagnetic simulation program based on the solution of the Landau-Lifshitz-Gilbert equation by finite difference numerical method approach. The hysteresis loop area, remanent magnetization, and coercive field values of the permalloy disk have been obtained as functions of the frequency and amplitude of the external sinusoidal magnetic field. In accordance with the simulation results obtained, a transition from a dynamically disordered phase to a dynamically ordered phase has been observed after a certain frequency value, and the phase transition region moved towards higher frequency values with increasing field amplitude. The triggered dynamical orders in other directions than the field have been observed for different frequency intervals. According to the shape effect of soft magnetic material, permalloy disk on dynamic behavior has been slowly reflected when the shape is concave. [ABSTRACT FROM AUTHOR]

This document is an editorial for a special issue of the journal "Materials" that focuses on "Soft Magnetic Materials and Their Applications." Soft magnetic materials are easily magnetized and demagnetized within magnetic fields and are used in electronics, energy conversion, and information processing. The special issue presents the latest advancements in the synthesis, characterization, and applications of soft magnetic materials, including soft ferrites, alloys, and composites. The papers cover topics such as improving high-frequency properties of soft ferrites, developing FeCo thin films for high-frequency electronic devices, and measuring and characterizing soft magnetic materials. The document discusses the applications of soft magnetic materials in electrical machines, motors, magnetic shielding structures, and atomic sensors. Various studies on the magnetic properties and performance of different soft magnetic materials are presented, suggesting their potential for enhancing the efficiency, sensitivity, and precision of electrical machines and sensors. The document concludes by acknowledging the authors and funding support for the research. [Extracted from the article]

The manufacturing processing of Electrical Steel Laminations (ESLs) for electric machines comprises cutting, stacking, and housing techniques which can result in plastic deformation and residual stress in the soft magnetic material. These manufacturing processes result in decreasing the magnetic quality and a local increase in both the static and dynamic hysteresis losses near the cut edges and consequently a reduction in the performance of the designed motor. The iron losses resulting from cutting can vary by a factor of two or more depending on geometrical, material, and processing parameters as well as the magnetic field strength. It is advantageous to consider these manufacturing effects in the design stage to reduce the probability of underperforming mass production. In this paper, the manufacturing processes of ESLs and their modelling methods are comprehensively surveyed. The gaps in scientific understanding and the research need for the expansion of accurate modelling of the cutting and joining of ESLs are subsequently discussed. [ABSTRACT FROM AUTHOR]

Cleanliness and microstructure significantly impact the magnetic properties of soft magnetic materials. This study investigates the impact of Mg treatment on the cleanliness, microstructure, and magnetic properties of Fe–80Ni alloy. The content of Mg ranges from 0% to 0.034%. The O and S contents can be reduced to 0.0006% and 0.0011%, respectively, when the content of Mg is 0.027%, and the number of inclusions is reduced. Simultaneously, the primary inclusions are modified to Mg‐containing inclusions. Based on electron backscattered diffraction results, Mg treatment can refine the deformed grain and enhance grain boundary energy after cold rolling. In addition, the grains exhibit enhanced growth after annealing with Mg treatment. Due to the improvement of cleanliness and microstructure, the magnetic properties of Fe–80Ni alloy are enhanced with Mg treatment. With Mg treatment, the coercivity of alloys is reduced, and maximum magnetic susceptibility (χmax) increases to 0.3247 with Mg treatment, while that is 0.1938 without Mg treatment. [ABSTRACT FROM AUTHOR]

Owing to its processing freedom, additive manufacturing has emerged as a promising material processing method for Fe–Si alloys. In this process, the melt pool fused by selective laser undergoes rapid cooling, which results in non-equilibrium solidifications. Therefore, it is essential to systematically investigate the relationship between process parameters, microstructure and magnetic properties of the Fe–Si alloys manufactured by the L-PBF process. However, the conventional experimental approaches require time-consuming and costly procedures and a great deal of trial and error. In this regard, an efficient and cost-effective tool is needed to investigate the effect of process parameters on the microstructure and magnetic properties under a wide range of process conditions. In this study, the processing parameter correlations were conducted based on the statistical methods using the design of experiments. Through this method, the effect of process parameters on various properties, including relative density, coercivity and saturation magnetisation, was systematically investigated. [ABSTRACT FROM AUTHOR]

An interfacial integration at the nanoscale domain through a core@shell (CS) nanostructure has constructively unbarred a wide dimension to researchers on biomedical applications, especially for magnetic fluid hyperthermia. Lately, the interconnection of the exchange bias effect (EBE) through the interface coupling to the magnetic heating efficiency has uttered its utmost prominence for researchers. Here, we delineate the ascendency of the heating ability through a coalescing assembly of mixed ferrite Co0.5Zn0.5 Fe2O4 (CZ) and soft magnetic material Fe3O4 (F), by devising a network of CoZnFe2O4@Fe3O4 (CZF) CS nanostructure. A hefty interface activity with validation of the EBE phenomenon is divulged through magnetic scrutiny for the CS sample. The magnetic nanoparticles heating response to applied magnetic field and frequency is discerned at three distinct fields, where the outcome prevailed to inflated specific loss power for CS CZF in distinction to bare F and CZ samples for all the assessments. Remarkably; a lofty intrinsic loss parameter is also perceived for the CS sample recorded to about 5.36 nHm2 g−1; which is another eccentric outcome that significantly labels the CS CZF sample as a potentially high heating competence agent. This comprehension accords to a finer perspective to meliorate the theranostic environment for hyperthermia applications. [ABSTRACT FROM AUTHOR]

Amorphous alloys are still a challenge for science when it comes to an accurate description of their structure and magnetic properties. There are many techniques for studying the structure, however, the direct observation of the amorphous structure does not bring much to the description of the phenomena occurring in them. In the case of ferromagnetic amorphous alloys, their properties can be studied based on the analysis of transmission Mössbauer spectra and the hyperfine field induction distributions obtained on their basis. The work investigated the influence of changing the surroundings of the central iron atom on the magnetic properties of a soft magnetic amorphous alloy. Samples after solidification and after isothermal annealing at a temperature below the crystallization temperature were tested. [ABSTRACT FROM AUTHOR]

Soft magnetic materials (SMMs) are extensively used in various fields such as power generation, energy transfer and electromagnetic interference damping. The preparation of SMMs in different forms requires expertise in diverse fabrication techniques. Furthermore, achieving optimal performance requires an understanding of the relationship between magnetic behavior and microstructure and mechanical properties of SMMs. This study focuses on analyzing the effects of accumulative roll-bonding (ARB) processing on the texture, microstructure, and magnetic properties of a commercial Permimphy alloy (Fe–80Ni–5Mo wt%). Electron BackScattered Diffraction (EBSD) analysis confirmed the expected refinement of the grain structure resulting from ARB processing, leading to a reduction in the transverse dimension of the elongated grain down to 800 nm after five cycles. The microhardness of the alloy increased by 80% compared to the as-received sample, primarily due to the refinement of the microstructure and the formation of a high density of dislocations. The findings suggest that the magnetic domain walls are more affected by low-angle boundaries rather than grain/high-angle boundaries. In addition, it was proved that subsequent annealing at 550 °C for one hour improved the alloy's magnetic softness while maintaining the mechanical hardness achieved through ARB deformation. This improvement was attributed mainly to the removal of stresses and defects in the material without initiating the process of recrystallization. [ABSTRACT FROM AUTHOR]

Nano-satellites, which are following the CubeSat standard are increasingly utilized for demanding industrial and astronomical applications with critical requirements on pointing and stability. Due to their small moment of inertia, even a small disturbance torque - caused by the residual magnetic moment - can result in a significant effect on the attitude. In order to study the magnetic moment of a 3 U CubeSat, an electrical model with a representative set of subsystems has been developed. A simulation tool was developed to calculate the magnetic field generated by the current flow inside the satellite. The simulation tool served to study the CubeSat mission so-called CLIMB, which employs a Field-emission electric propulsion electric propulsion system to rise its orbit by 500 km with a power consumption of 40 W at operation. In this context, the magnetic fields of this high energy density nano-satellite were measured for different operation modes inside the magnetic test facility of IABG. The data were correlated to the simulation results of the automatized model. It demonstrates, that the magnetic dipole moment is dominated by soft and hard magnetic materials like Li-ion batteries, especially at the discharging modes. This results in magnetic dipole moments of 14 mAm2 to 18 mAm2 for discharging and in between 4 mAm2 and 6 mAm2 for charging modes. The simulation tool was verified by a comparison with multi dipole models of the satellite and by modeling the impact of the solar panels only. [ABSTRACT FROM AUTHOR]

From portable electronics to high-performance computing, the requirement for miniaturized and high-efficiency power supply is ever-increasing. Soft magnetic material with higher resistivity and moderate anisotropy field can be considered as a promising candidate as core materials for high-frequency integrated magnetic passives leading to such on-chip power supply devices. Here, in-plane magnetic orientation (φ )dependent ultrafast magnetization dynamics of electrodeposited cobalt phosphorus (CoP) alloy are investigated with partial demagnetization within few hundreds of femtoseconds (fs) followed by fast and slow relaxation in relatively longer timescale. The precession frequency extracted from the magnetization precession shows dominant two-fold anisotropy superposed with a moderate four-fold anisotropy, whereas the Gilbert damping coefficient reveals a four-fold anisotropy as a function of φ . On the contrary, the ultrafast demagnetization is found to be nearly isotropic with φ . We can speculate that spin–orbit coupling (SOC) plays a major role in these anisotropic precessional dynamics but for highly non-equilibrium dynamics, the role of anisotropic SOC is negligible for ultrafast spin-flip scattering process. Such detailed studies of ultrafast spin dynamics revealing important dynamical properties will underpin potential applications in high-frequency integrated magnetic passives for future monolithic power supply on-chip. [ABSTRACT FROM AUTHOR]

In this article, we study the effect of annealing temperature and applied stress on the magnetic properties of Fe 71.80 B 13.27 Si 11.02 Nb 2.99 Ni 0.92 and Co 65.34 Si 12.00 B 10.20 Cr 8.48 Fe 3.90 Mo 0.08 microwires. An anomalous behavior of the coercive field is observed while applying stress, indicating nontrivial changes in the microwire magnetic anisotropy. The effect of applied stimuli on the magnetic anisotropy and magnetostriction constant in both microwires is also discussed. [ABSTRACT FROM AUTHOR]

Ni-Zn ferrites have important applications in the field of soft magnetic materials due to their excellent magnetic properties, but their high bulk density hinders their widespread use. CNT/nickel-zinc ferrite (CNT/Ni0.5Zn0.5Fe2O4) nanocomposites was prepared by sol-gel method, and sintered at 1000 °C to be used as an electromagnetic wave absorber. The results showed that the morphology, impedance matching, density, electrical conductivity and absorption coefficient of CNT/Ni-Zn ferrite was controlled by the additional CNT content. The NZ3 sample containing 0.06 g of CNT showed high conductivity, and high absorption coefficient. The amount of 0.06 g of CNT was a critical amount for the CNT/Ni-Zn ferrite nanocomposites. Above this value, the increasing trend toward improved nanocomposite properties due to the agglomeration of CNTs was reversed. The absorption performance of the CNT/Ni-Zn ferrite nanocomposites are attributed to the incorporation of dielectric and magnetic loss mechanisms in which the magnetic portion is comparable to the dielectric portion. Possessing excellent magnetic and absorption properties, it has the potential to be an excellent electromagnetic wave absorbing material. [ABSTRACT FROM AUTHOR]

In this article, an efficient multi-objective optimization strategy for the Halbach array permanent magnet synchronous machine (PMSM) is developed by taking into consideration the nonlinear B-H behavior of soft magnetic materials. Based on the harmonic modeling (HM) technology, the electromagnetic performances (EPs) of the Halbach array PMSM can be computed. To specifically model the local magnetic saturation, the stator teeth are separated into several annular layers, and each tooth is further divided into several regions along the tangential direction. Then, the parameters of the Halbach array PMSM are optimized utilizing combined nonlinear semi-analytical model (SAM) and non-dominated sorting genetic algorithm II (NSGA-II). To validate the effectiveness and accuracy of the developed optimization scheme, a Halbach array prototype is then manufactured in accordance with the optimization results. The multi-objective rapid optimization strategy developed in this article, which includes but is not limited to Halbach array permanent magnet (PM) machines, serves as a reference for the design and optimization of various PM machines. [ABSTRACT FROM AUTHOR]

Three-dimensional printing is a promising technology that offers increased freedom to create topologically optimised electrical machine designs with a much smaller layer thickness achievable with the current, laminated steel-sheet-based technology. These composite materials have promising magnetic behaviour, which can be competitive with the current magnetic materials. Accurately calculating the iron losses is challenging due to magnetic steels' highly nonlinear hysteretic behaviour. Many numerical methodologies have been developed and applied in FEM-based simulations from the first introduced Steinmetz formulae. However, these old curve-fitting-based iron loss models are still actively used in modern finite-element solvers due to their simplicity and high computational demand for more-accurate mathematical methods, such as Preisach- or Jiles–Atherton-model-based calculations. In the case of 3D-printed electrical machines, where the printed material can have a strongly anisotropic behaviour and it is hard to define a standardised measurement, the applicability of the curve-fitting-based iron loss methodologies is limited. The following paper proposes an overview of the current problems and solutions for iron loss calculation and measurement methodologies and discusses their applicability in designing and optimising 3D-printed electrical machines. [ABSTRACT FROM AUTHOR]

The importance of amorphous and nanocrystalline Fe-based soft magnetic materials is increasing annually. Thus, characterisation of the chemical compositions, alloying additives, and crystal structures is significant for obtaining the appropriate functional properties. The purpose of this work is to present comparative studies on the influence of Nb (1, 2, 3 at.%) and Mo (1, 2, 3 at.%) in Fe substitution on the thermal stability, crystal structure, and magnetic properties of a rapidly quenched Fe79.4Co5Cu0.6B15 alloy. Additional heat treatments in a vacuum (260–640 °C) were performed for all samples based on the crystallisation kinetics. Substantial improvement in thermal stability was achieved with increasing Nb substitution, while this effect was less noticeable for Mo-containing alloys. The heat treatment optimisation process showed that the least lossy states (with a minimum value of coercivity below 10 A/m and high saturation induction up to 1.7 T) were the intermediate state of the relaxed amorphous state and the nanocomposite state of nanocrystals immersed in the amorphous matrix obtained by annealing in the temperature range of 340–360 °C for 20 min. Only for the alloy with the highest thermal stability (Nb = 3%), the α-Fe(Co) nanograin grows, without the co-participation of the hard magnetic Fe3B, in a relatively wide range of annealing temperatures up to 460 °C, where the second local minimum in coercivity and core power losses exists. For the remaining annealed alloys, due to lower thermal stability than the Nb = 3% alloy, the Fe3B phase starts to crystallise at lower annealing temperatures, making an essential contribution to magneto-crystalline anisotropy, thus the substantial increase in coercivity and induction saturation. The air-annealing process tested on the studied alloys for optimal annealing conditions has potential use for this type of material. Additionally, optimally annealed Mo-containing alloys are less lossy materials than Nb-containing alloys in a frequency range up to 400 kHz and magnetic induction up to 0.8 T. [ABSTRACT FROM AUTHOR]

An interior permanent magnet synchronous motor (IPMSM) is characterized by its high efficiency. However, torque ripple and loss occur because of the spatial harmonics generated by air‐gap permeance fluctuations. This study clarified that slot harmonic components can be suppressed by inserting magnetic wedges made of magnetic composite material in the slot opening of an IPMSM. First, the authors examined the torque and loss characteristics by varying relative permeability and saturation magnetic flux density of magnetic wedges using finite element analysis (FEA). Results indicated that the torque ripple and loss could be suppressed when the relative permeability of the magnetic wedge was μr = 10 to 22 and the saturation magnetic flux density was Bs = 0.5 to 0.75 T. Furthermore, the authors produced magnetic composite materials made of various soft magnetic material powders and examined their magnetic properties and viscosities. Results showed that a magnetic composite material with optimal magnetic properties and injectable viscosity could be manufactured using Fe‐Si‐Al with a low volume fraction. [ABSTRACT FROM AUTHOR]

In order to accurately describe the hysteresis and loss characteristics of soft magnetic materials, a nonlinear Preisach model is introduced to simulate the hysteresis characteristics of three soft magnetic materials, and the dynamic distribution parameters of the nonlinear model are determined by experimentally measuring the data of the first-order reversal curves and second-order reversal curves of three soft magnetic materials under DC static magnetic fields. Comparing the static limit hysteresis lines of soft magnetic materials, it is proved that the model can describe the hysteresis characteristics of soft magnetic materials more accurately. Combined with the loss separation principle, a more accurate loss prediction method for soft magnetic materials is proposed. By comparing the experimental results of loss separation of different soft magnetic materials under different working conditions with the calculated results, it is found that they are in good agreement, which shows that the dynamic loss model can better describe the magnetic loss of soft magnetic materials and each component and verify the correctness and generality of the model. [ABSTRACT FROM AUTHOR]

Soft magnetic materials are a kind of promising materials for antenna substrates because their permeability and permittivity are both greater than unity. However, their magnetic properties would deteriorate dramatically as the frequency reaches 1 GHz owing to Snoek limit and domain wall resonance, thus limiting their application at high frequency. Here, we report a low-dimensional soft magnetic composite (SMC) prepared by FeB nanochains, achieving the optimized magnetic loss tangent ( tan δ μ ) of 0.09 and the real part of permeability ( μ ′ ) of 3.3 at 1 GHz, which is more competitive than the conventional spherical FeB SMCs. Such an optimization is ascribed to the change in the dominant mechanism of the magnetization process from domain wall motion to magnetic moment precession, associated with the transition of the magnetic domain structure of the particles from multi- to mono-domain. The SMC proposed in this work provides a significantly potential candidate for high-frequency and miniaturized 5G antennas. Furthermore, the design concept and preparation method can be extended to other SMCs, providing a guidance for the development of high-performance antenna substrate materials. [ABSTRACT FROM AUTHOR]

An interfacial integration at the nanoscale domain through a core@shell (CS) nanostructure has constructively unbarred a wide dimension to researchers on biomedical applications, especially for magnetic fluid hyperthermia. Lately, the interconnection of the exchange bias effect (EBE) through the interface coupling to the magnetic heating efficiency has uttered its utmost prominence for researchers. Here, we delineate the ascendency of the heating ability through a coalescing assembly of mixed ferrite Co0.5Zn0.5 Fe2O4 (CZ) and soft magnetic material Fe3O4 (F), by devising a network of CoZnFe2O4@Fe3O4 (CZF) CS nanostructure. A hefty interface activity with validation of the EBE phenomenon is divulged through magnetic scrutiny for the CS sample. The magnetic nanoparticles heating response to applied magnetic field and frequency is discerned at three distinct fields, where the outcome prevailed to inflated specific loss power for CS CZF in distinction to bare F and CZ samples for all the assessments. Remarkably; a lofty intrinsic loss parameter is also perceived for the CS sample recorded to about 5.36 nHm2 g−1; which is another eccentric outcome that significantly labels the CS CZF sample as a potentially high heating competence agent. This comprehension accords to a finer perspective to meliorate the theranostic environment for hyperthermia applications. [ABSTRACT FROM AUTHOR]

Magnetic skyrmions, topological quasiparticles, are small stable magnetic textures that possess intriguing properties and potential for data storage applications. Hybrid nanostructures comprised of skyrmions and soft magnetic material can offer additional advantages for developing skyrmion-based spintronic and magnonic devices. We show that a Néel-type skyrmion confined within a nanodot placed on top of a ferromagnetic in-plane magnetized stripe produces a unique and compelling platform for exploring the mutual coupling between magnetization textures. The skyrmion induces an imprint upon the stripe, which, in turn, asymmetrically squeezes the skyrmion in the dot, increasing their size and the range of skyrmion stability at small values of Dzyaloshinskii–Moriya interaction, as well as introducing skyrmion bi-stability. Finally, by exploiting the properties of the skyrmion in a hybrid system, we demonstrate unlimited skyrmion transport along a racetrack, free of the skyrmion Hall effect. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) is an attractive set of processes that are being employed lately to process specific materials used in the fabrication of electrical machine components. This is because AM allows for the preservation or enhancement of their magnetic properties, which may be degraded or limited when manufactured using other traditional processes. Soft magnetic materials (SMMs), such as Fe–Si, Fe–Ni, Fe–Co, and soft magnetic composites (SMCs), are suitable materials for electrical machine additive manufacturing components due to their magnetic, thermal, mechanical, and electrical properties. In addition to these, it has been observed in the literature that other alloys, such as soft ferrites, are difficult to process due to their low magnetization and brittleness. However, thanks to additive manufacturing, it is possible to leverage their high electrical resistivity to make them alternative candidates for applications in electrical machine components. It is important to highlight the significant progress in the field of materials science, which has enabled the development of novel materials such as high-entropy alloys (HEAs). These alloys, due to their complex chemical composition, can exhibit soft magnetic properties. The aim of the present work is to provide a critical review of the state-of-the-art SMMs manufactured through different AM technologies. This review covers the influence of these technologies on microstructural changes, mechanical strengths, post-processing, and magnetic parameters such as saturation magnetization (MS), coercivity (HC), remanence (Br), relative permeability (Mr), electrical resistivity (r), and thermal conductivity (k). [ABSTRACT FROM AUTHOR]

A vehicle's solenoid valve-actuated shock (SVSA) absorber is of wide interest because of its adjustable damping characteristics. The proportional solenoid valve is a pivotal component for commanding damping force, but the research on its model principle still needs to be improved. Therefore, this research aimed to establish an accurate model of the proportional solenoid valve composed of the pilot valve and relief valve. In the pilot valve, we proposed a valve spool structure using a two-stage combined throttling groove to control flow accurately. Then, the dynamic equation of the spool was established, and it is also considered that the magnetic saturation of soft magnetic materials impacts electromagnetic force. The flow force in the dynamic equation was numerically solved by the CFD method. The flow rate in the relief valve was analyzed from the deformation of the lamination valves and main valve plate through the small deflections thin plate theory. Then, the SVSA bench test was carried out. The results show good agreement between the test and calculation, and the maximum error is within 9 %. It is indicated that the model of the SVSA equipped with the proportional solenoid valve has high accuracy. [ABSTRACT FROM AUTHOR]

Materials with so-called soft magnetic properties are an important object of material engineering research due to their potentialapplication, among others, in the construction of low-loss transformer cores. Such properties are typical for alloys with an amorphous structureand with a high content of ferromagnetic elements: Fe, Co, Ni. Difficulties related with obtaining alloys which meet satisfactory dimensions resultin the search for new solutions. One of them is the production of composites based on ferromagnetic powders obtained from amorphous alloys.This paper presents results of structure research for composite materials produced in a multi-stage production process. Magnetic compositeswere made on the basis of a bulk amorphous Fe70B20Y5Nb4Mo1 alloy produced by the injection method. On the basis of the obtained powder,two series of moldings were made: with 0.5% resin and covered with high-temperature varnish. Final composites were produced by using hightemperature isostatic press. On the basis of the conducted research, it was found that the composites without resin are characterized by distinctlybetter magnetic properties as compared to resin-bonded composites. [ABSTRACT FROM AUTHOR]

In the present study, Fe1.1(CrxMn1-x)1.9O4 nanoparticles (0 ≤ x ≤ 0.5) were successfully synthesized by a combustion method, and the influence of Cr substitution on the structural and magnetic properties of the obtained nanoparticles was studied by various methods. The structural analysis revealed that the sample with x = 0 has a tetragonal structure, while all Cr-doped samples crystallize into a cubic structure. Additionally, the results of TEM show that doping with chromium leads to an increase in particle size. The magnetic hysteresis loops demonstrate the behavior typical for soft magnetic materials with low coercivity and remanence magnetization. The magnetic measurements revealed that the saturation magnetization of the obtained nanoparticles demonstrates a decreasing trend with increasing Cr content. The influence of chromium doping on the observation change in saturation magnetization is discussed. Based on the results of temperature-dependent magnetization measurements, it was found that the temperature of a magnetic transition in synthesized nanoparticles depends on Cr content. [ABSTRACT FROM AUTHOR]

Fe‐based amorphous and nanocrystalline alloys are widely used in transformers, electronic information, and aerospace applications due to their high saturation flux density (Bs), high permeability, low iron loss, and low coercivity (Hc). This article briefly introduces soft magnetic materials, gives an overview of the classification, preparation methods, soft magnetic properties, and applications of Fe‐based amorphous and nanocrystalline alloys, and reviews the effects of elements such as Fe, Co, Ni, Si, B, P, and Nb in the alloys on the properties of Fe‐based amorphous and nanocrystalline alloys such as amorphous forming ability, Bs and Hc. The challenges and development directions of Fe‐based amorphous and nanocrystalline alloys in research are pointed out. [ABSTRACT FROM AUTHOR]

Nanopowder of iron oxide (mainly Fe 3 O 4) has been obtained by electroerosion dispersion method and was used for manufacturing of gradient polymer-based microwave absorbing materials which absorb (1) on 36.6 GHz with a level of absorption of 99% (with a maximum penetration −40 dB and reflection −23 dB) and (2) on 10 GHz and 36.6 GHz with an absorption of 90% and 98.4%, correspondently (with a maximum reflection −18 dB and −10 dB and penetration −40 dB and −60 dB, respectively). It was demonstrated, that change of magnetic properties of the absorbing material under mechanical load can be used for non-destructive control. Sintered under high pressure-high temperature conditions (2 GPa, at 900, 1000, 1100, 1200 and 1300 °C for 4 min) iron oxide nanopowder in presence of hexagonal boron nitride (hBN) demonstrated soft magnetic behavior. Electron Backscatter Diffraction (EBSD) study has showed that during sintering the grains have grown beyond the superparamagnetic size limit inspire short annealing time. The structure of sintered materials was investigated using X-ray diffraction with a full-profile fitting procedure. The materials sintered at 2 GPa at 900 and 1000 °C contained 75–80 wt% of FeO and 25–20 wt% Fe. Materials sintered at 1100 oC, along with 32 wt% FeO and 2 wt% Fe, contained a significant amount of Fe 3 N: 66 wt%. However, materials sintered at 1200–1300 °C contain almost pure Fe 3 N phase. Thus, under conditions of high pressures and temperatures with increasing sintering temperature, reduction of iron oxide was observed, followed by its nitriding with nitrogen released from the boron nitride, which led to a reduction of coercive force and thus improving soft magnetic characteristics of the sintered materials. The scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX) study of the sample, sintered at 1300 oC showed approximate composition of Fe 3 N 0.8 C 0.3-0.6 O 0.06-0.3. [ABSTRACT FROM AUTHOR]

Manganese-Zinc (Mn-Zn) ferrite is a ceramic and soft magnetic material, which can be, used for the fabrication of passive elements integrated in power converters. The main, challenge related to these converters rely on their miniaturization and efficiency, enhancement. Digital Light Processing (DLP) is a potential additive manufacturing, technique to fabricate fine and complex Mn-Zn ferrite components. This paper focuses, on the analysis of the optical properties of the formulations containing Mn-Zn ferrite, powder. Different particle's sizes (71–1.3 µm) were used to study the influence of the, cured monolayer evolution and the optical properties of the ferrite. We compared, experimental data obtained on formulations with a low content of ferrite particles, (15%.wt) to the results issued from the Mie theory. High solid content (75%.wt) were, investigated to cover the practical applications of DLP and the role of light scattering, was analyzed and discussed in detail for this specific configuration. [ABSTRACT FROM AUTHOR]

This paper reports on structure and phase formation of a Ni–Al–Co based alloy prepared by self-propagating high-temperature synthesis. The maximum combustion temperature was 1020°C in argon and 913°C in vacuum. The phase composition of the synthesized alloy includes a Ni0.7Co0.3 solid solution with a cubic (Pm m) crystal lattice. Its microstructural constituents based on γ- and β-phases are 10–20 μm in size, and γ + β interlayers located on the interface between the γ- and β-phases are up to 1–2 μm in thickness. The alloy offers high plasticity, and its compressive strength is 451 MPa. Its low remanence, low coercive force, and high saturation magnetization indicate that the alloy is a soft magnetic material. It has a coercive force Hc = 146 Oe, remanent magnetization σr = 0.35 emu/g, and saturation magnetization σs = 36.76 emu/g. [ABSTRACT FROM AUTHOR]

This paper deals with the noise level of power transformers operating at a middle frequency from 800 Hz to 2000 Hz. The factors that influence the noise produced by power transformers are size, design and operating conditions. The research shows that the noise level of power transformers can vary widely depending on these factors. The paper discusses an overview of different types of power transformers core and their impact on the transformer's noise performance. This paper describes the design of a middle-frequency power transformer, its material composition and the design of the magnetic circuit and windings, operating in the frequency range 800 to 2000 Hz, with a capacity of 200 kVA, air-cooled, to be fed from a suitable frequency converter, characterized by reduced noise. The proposed solution allows implementation of galvanically isolated DC-DC converters for auxiliary traction drives and other DC-DC converters. [ABSTRACT FROM AUTHOR]