Pub Date : 2025-11-25DOI: 10.1109/TMAG.2025.3636893
S. Clénet;J. Korecki;H. Igarashi;S. Yin;X. Kong
This article proposes a forward method to determine the optimal direction of the magnetization of permanent magnets, as well as their optimal shape, in order to maximize the magnetic flux in a coil. The method can be advantageously used, for example, during the design stage of an electrical machine in order to maximize the flux in the stator windings generated by the permanent magnets located on the rotor. The method is first developed in the continuous domain. It appears that the optimal permanent magnet configuration can be determined from the magnetic flux density distribution generated by the coil when it is supplied by a current of 1 A. No need to solve any inverse problem to find the optimal configuration since the procedure is explicit. It is shown that this method remains valid in the discrete domain when the finite element method is applied, and can take advantage of this method for topology optimization. Two configurations of permanent magnet magnetization are considered: either having a continuously variable direction or made with blocks in which the direction is constant as in a Halbach array. In the same way, for topology optimization, two cases are considered when the magnetization is fixed or considered as a variable to be optimized. A 3-D example is treated in order to illustrate the effectiveness of the method.
{"title":"A Forward Approach for Topology Optimization and Magnetization Direction Optimization of Permanent Magnets","authors":"S. Clénet;J. Korecki;H. Igarashi;S. Yin;X. Kong","doi":"10.1109/TMAG.2025.3636893","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3636893","url":null,"abstract":"This article proposes a forward method to determine the optimal direction of the magnetization of permanent magnets, as well as their optimal shape, in order to maximize the magnetic flux in a coil. The method can be advantageously used, for example, during the design stage of an electrical machine in order to maximize the flux in the stator windings generated by the permanent magnets located on the rotor. The method is first developed in the continuous domain. It appears that the optimal permanent magnet configuration can be determined from the magnetic flux density distribution generated by the coil when it is supplied by a current of 1 A. No need to solve any inverse problem to find the optimal configuration since the procedure is explicit. It is shown that this method remains valid in the discrete domain when the finite element method is applied, and can take advantage of this method for topology optimization. Two configurations of permanent magnet magnetization are considered: either having a continuously variable direction or made with blocks in which the direction is constant as in a Halbach array. In the same way, for topology optimization, two cases are considered when the magnetization is fixed or considered as a variable to be optimized. A 3-D example is treated in order to illustrate the effectiveness of the method.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"62 1","pages":"1-11"},"PeriodicalIF":1.9,"publicationDate":"2025-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11268310","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145847766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-25DOI: 10.1109/TMAG.2025.3637158
Jan Pytlík;Ondřej Životský;Jiří Luňáček
In the article, experimentally measured magnetization curves obtained on an amorphous Fe77.5Si7.5B15 ribbon at room and elevated temperatures are fit using the differential isotropic model of ferromagnetic hysteresis (DIMFH). The temperature dependence of the DIMFH model parameters is analyzed both in the ferromagnetic region and near the Curie temperature and is related to the size of magnetic clusters. The simple two-level model with Weiss approximation is used to fit the temperature dependence of saturation magnetization.
{"title":"Differential Isotropic Model of Ferromagnetic Hysteresis: Temperature Dependence of Saturation Magnetization and Cluster Magnetic Moment","authors":"Jan Pytlík;Ondřej Životský;Jiří Luňáček","doi":"10.1109/TMAG.2025.3637158","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3637158","url":null,"abstract":"In the article, experimentally measured magnetization curves obtained on an amorphous Fe77.5Si7.5B15 ribbon at room and elevated temperatures are fit using the differential isotropic model of ferromagnetic hysteresis (DIMFH). The temperature dependence of the DIMFH model parameters is analyzed both in the ferromagnetic region and near the Curie temperature and is related to the size of magnetic clusters. The simple two-level model with Weiss approximation is used to fit the temperature dependence of saturation magnetization.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"62 1","pages":"1-4"},"PeriodicalIF":1.9,"publicationDate":"2025-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145847765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-20DOI: 10.1109/TMAG.2025.3635521
Seth Stewart;Joseph Pawelski;Steve Ward;Andrew J. Petruska
Extending the field of magnetic manipulation to conductive, non-magnetic objects opens the door for a wide array of applications previously limited to hard or soft magnetic materials. Of particular interest is the recycling of space debris through the use of oscillating magnetic fields, which represent a cache of raw materials in an environment particularly suited to the low forces generated from inductive magnetic manipulation. Building upon previous work that demonstrated 3-D open-loop position control by leveraging the opposing dipole moment created from induced eddy currents, this work demonstrates closed-loop position control of a semibuoyant aluminum sphere in laboratory tests, and the efficacy of varying methods for force inversion is explored. The closed-loop methods represent a critical first step toward wider applications for 3-DOF position control of induced magnetic dipoles.
{"title":"Non-Contact Manipulation of Induced Magnetic Dipoles","authors":"Seth Stewart;Joseph Pawelski;Steve Ward;Andrew J. Petruska","doi":"10.1109/TMAG.2025.3635521","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3635521","url":null,"abstract":"Extending the field of magnetic manipulation to conductive, non-magnetic objects opens the door for a wide array of applications previously limited to hard or soft magnetic materials. Of particular interest is the recycling of space debris through the use of oscillating magnetic fields, which represent a cache of raw materials in an environment particularly suited to the low forces generated from inductive magnetic manipulation. Building upon previous work that demonstrated 3-D open-loop position control by leveraging the opposing dipole moment created from induced eddy currents, this work demonstrates closed-loop position control of a semibuoyant aluminum sphere in laboratory tests, and the efficacy of varying methods for force inversion is explored. The closed-loop methods represent a critical first step toward wider applications for 3-DOF position control of induced magnetic dipoles.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"62 1","pages":"1-13"},"PeriodicalIF":1.9,"publicationDate":"2025-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145847833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-20DOI: 10.1109/TMAG.2025.3635285
M. Šoka;M. Ušáková;R. Dosoudil;V. Jančárik;J. Škriniarová;E. Ušák
The effect of lanthanum (La) substitution and sintering temperature variation on the selected parameters of nickel–zinc ferrites was the subject of our analysis. To determine the structural parameters, we used X-ray diffraction (XRD) along with scanning electron microscopy (SEM) micrographs. The magnetic properties of ferrites were measured by applying the methods of thermomagnetic analysis and using the hysteresis loop measurements. Moreover, to analyze the magnetic behavior of prepared polymer composites, we used the results of measuring the frequency dependences of the complex permeability. The ferrite filler content in all the investigated composites was 60 vol% and epoxy resin was used as the polymer matrix. The conducted research represents a comprehensive study of doped ferrites covering a remarkable range of sintering temperatures at a constant ratio of input materials.
{"title":"Lanthanum-Substituted Nickel–Zinc Ferrites Used as Fillers for Composites","authors":"M. Šoka;M. Ušáková;R. Dosoudil;V. Jančárik;J. Škriniarová;E. Ušák","doi":"10.1109/TMAG.2025.3635285","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3635285","url":null,"abstract":"The effect of lanthanum (La) substitution and sintering temperature variation on the selected parameters of nickel–zinc ferrites was the subject of our analysis. To determine the structural parameters, we used X-ray diffraction (XRD) along with scanning electron microscopy (SEM) micrographs. The magnetic properties of ferrites were measured by applying the methods of thermomagnetic analysis and using the hysteresis loop measurements. Moreover, to analyze the magnetic behavior of prepared polymer composites, we used the results of measuring the frequency dependences of the complex permeability. The ferrite filler content in all the investigated composites was 60 vol% and epoxy resin was used as the polymer matrix. The conducted research represents a comprehensive study of doped ferrites covering a remarkable range of sintering temperatures at a constant ratio of input materials.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"62 1","pages":"1-4"},"PeriodicalIF":1.9,"publicationDate":"2025-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145847838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-19DOI: 10.1109/TMAG.2025.3634275
P. Pillárová;I. Antal;I. Khmara;V. Závišová;M. Kubovčíková;A. Juríková;V. Jedinák;J. Kováč;M. Koneracká
Recent advancements in nanoscience have demonstrated the enzyme-mimicking capabilities of iron oxide nanoparticles. In this study, the peroxidase-like activity of iron oxide nanoparticles coated with polyvinyl alcohol (PVA) of different molecular weights was investigated. The results revealed that magnetic nanoparticles (MNPs) coated with a lower molecular weight PVA exhibited a higher substrate affinity toward N, N-diethyl-p-phenylenediamine sulfate (DPD), suggesting enhanced catalytic efficiency at lower substrate concentrations.
{"title":"Polyvinyl Alcohol-Coated Magnetic Nanoparticles for Biomedical Applications","authors":"P. Pillárová;I. Antal;I. Khmara;V. Závišová;M. Kubovčíková;A. Juríková;V. Jedinák;J. Kováč;M. Koneracká","doi":"10.1109/TMAG.2025.3634275","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3634275","url":null,"abstract":"Recent advancements in nanoscience have demonstrated the enzyme-mimicking capabilities of iron oxide nanoparticles. In this study, the peroxidase-like activity of iron oxide nanoparticles coated with polyvinyl alcohol (PVA) of different molecular weights was investigated. The results revealed that magnetic nanoparticles (MNPs) coated with a lower molecular weight PVA exhibited a higher substrate affinity toward N, N-diethyl-p-phenylenediamine sulfate (DPD), suggesting enhanced catalytic efficiency at lower substrate concentrations.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"62 1","pages":"1-4"},"PeriodicalIF":1.9,"publicationDate":"2025-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145847798","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-19DOI: 10.1109/TMAG.2025.3634805
Xin Wang;Chuan Zhao;Shuoyu Wang;Junjie Jin;Feng Sun
The magnetic levitation conveyor system consists of two primary components: the levitation system and the drive system. This article proposes a drive system for a long stroke magnetic levitation conveyor. The mover has the characteristics of low mass, high-frequency noise suppression, fast dynamic response, and low disturbance. First, the no-load magnetic field model is developed using the equivalent surface current method. Subsequently, the parameters of the drive system are modeled and analyzed. Utilizing these parameters as fundamental inputs, a state-space equation for the system is established. Furthermore, to account for the mechanical and electrical coupling of the bilateral mover, parameter asymmetry, and mutual-inductance coupling are incorporated into the state-space equations, resulting in a model of the drive system. The open-loop response is analyzed to reveal the inherent characteristics and dynamic behaviors of the drive system. Finally, based on the inherent characteristics of the drive system, the fractional-order proportional–integral–derivative (FOPID) controller is designed for displacement and speed control. Moreover, the particle swarm optimization (PSO) algorithm is employed to optimize multiple controller parameters. Experimental results demonstrate that the controller parameters optimized using the PSO algorithm ensure stable displacement control. Additionally, the displacement precision of the magnetic drive system is enhanced by the FOPID controller. Experimental verification confirms that the analytical model achieves high computational accuracy.
{"title":"Characteristic Analysis and Displacement Control of Magnetic Drive System for Magnetic Levitation Conveyor","authors":"Xin Wang;Chuan Zhao;Shuoyu Wang;Junjie Jin;Feng Sun","doi":"10.1109/TMAG.2025.3634805","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3634805","url":null,"abstract":"The magnetic levitation conveyor system consists of two primary components: the levitation system and the drive system. This article proposes a drive system for a long stroke magnetic levitation conveyor. The mover has the characteristics of low mass, high-frequency noise suppression, fast dynamic response, and low disturbance. First, the no-load magnetic field model is developed using the equivalent surface current method. Subsequently, the parameters of the drive system are modeled and analyzed. Utilizing these parameters as fundamental inputs, a state-space equation for the system is established. Furthermore, to account for the mechanical and electrical coupling of the bilateral mover, parameter asymmetry, and mutual-inductance coupling are incorporated into the state-space equations, resulting in a model of the drive system. The open-loop response is analyzed to reveal the inherent characteristics and dynamic behaviors of the drive system. Finally, based on the inherent characteristics of the drive system, the fractional-order proportional–integral–derivative (FOPID) controller is designed for displacement and speed control. Moreover, the particle swarm optimization (PSO) algorithm is employed to optimize multiple controller parameters. Experimental results demonstrate that the controller parameters optimized using the PSO algorithm ensure stable displacement control. Additionally, the displacement precision of the magnetic drive system is enhanced by the FOPID controller. Experimental verification confirms that the analytical model achieves high computational accuracy.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"62 1","pages":"1-14"},"PeriodicalIF":1.9,"publicationDate":"2025-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145847767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-14DOI: 10.1109/TMAG.2025.3633161
P. Hrubovčák;L’. Nagy;A. Zeleňáková;D. Volavka;M. Abdolrahimi;A. Omelyanchik;D. Peddis
Using the thermal decomposition method, we have prepared monodisperse cobalt ferrite nanoparticles (CoFe2O4 NPs) of average size ~12 nm. A ligand exchange process was carried out to replace the post-synthesis hydrophobic oleic acid (OA) coating with hydrophilic polyacrylic acid (PAA). X-ray photoelectron spectroscopy (XPS) confirmed the successful ligand exchange process, and zeta potential measurements validated long-term stability in water in a broad pH range due to a significant negative charge of PPA-coated samples (−30 mV). Importantly, the magnetic behavior remains essentially unchanged with saturation magnetization (~65 A · m2/kg) and coercivity (~80 mT) at 300 K for samples before and after ligand exchange. In addition, δm plots confirmed moderate dipoledipole interparticle magnetic interactions, which remained consistent after surface modification. These findings demonstrate that surface functionalization with PAA preserves the key magnetic features of CoFe2O4 NPs, while providing stability in aqueous media for further biomedical applications.
{"title":"Polyacrylic Acid Ligand Exchange in Cobalt Ferrite Nanoparticles: Aqueous Stability Without Compromising Magnetic Properties","authors":"P. Hrubovčák;L’. Nagy;A. Zeleňáková;D. Volavka;M. Abdolrahimi;A. Omelyanchik;D. Peddis","doi":"10.1109/TMAG.2025.3633161","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3633161","url":null,"abstract":"Using the thermal decomposition method, we have prepared monodisperse cobalt ferrite nanoparticles (CoFe2O4 NPs) of average size ~12 nm. A ligand exchange process was carried out to replace the post-synthesis hydrophobic oleic acid (OA) coating with hydrophilic polyacrylic acid (PAA). X-ray photoelectron spectroscopy (XPS) confirmed the successful ligand exchange process, and zeta potential measurements validated long-term stability in water in a broad pH range due to a significant negative charge of PPA-coated samples (−30 mV). Importantly, the magnetic behavior remains essentially unchanged with saturation magnetization (~65 A · m2/kg) and coercivity (~80 mT) at 300 K for samples before and after ligand exchange. In addition, δm plots confirmed moderate dipoledipole interparticle magnetic interactions, which remained consistent after surface modification. These findings demonstrate that surface functionalization with PAA preserves the key magnetic features of CoFe2O4 NPs, while providing stability in aqueous media for further biomedical applications.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"62 1","pages":"1-5"},"PeriodicalIF":1.9,"publicationDate":"2025-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145847822","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-13DOI: 10.1109/TMAG.2025.3632247
Hongchao Cui;Xiong Jin;Heng Zhou;Tong Zhang;Huifang Ma;Decai Li;Zhenkun Li
To advance the development of magnetorheological display technology, this research explores the synergistic application of magnetic fluids and permanent magnets. The study focused on magnetic fluids with a saturation magnetization of 15.54 emu/g. Through the design of a permanent magnet deflection mechanism and magnetic field simulation testing, it established the maximum permissible distance between the permanent magnet and the display screen during magnetic fluid adsorption. This provides crucial structural design parameters for magnetic fluid displays. Building upon this foundation, the research further proposed a control scheme for the magnetohydrodynamic digital clock and successfully fabricated a prototype device. In addition, the methodology used in this study enabled the display of the Chinese character “horse” as a magnetohydrodynamic pattern. This study not only validates the feasibility of applying magnetic fluids and permanent magnets in the field of magnetohydrodynamic displays but also provides novel insights and practical references for advancing magnetohydrodynamic display technology through the determination of key parameters and display scheme design.
{"title":"Magnetofluidic Display Technology and Clock Design Based on Permanent Magnet Drive","authors":"Hongchao Cui;Xiong Jin;Heng Zhou;Tong Zhang;Huifang Ma;Decai Li;Zhenkun Li","doi":"10.1109/TMAG.2025.3632247","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3632247","url":null,"abstract":"To advance the development of magnetorheological display technology, this research explores the synergistic application of magnetic fluids and permanent magnets. The study focused on magnetic fluids with a saturation magnetization of 15.54 emu/g. Through the design of a permanent magnet deflection mechanism and magnetic field simulation testing, it established the maximum permissible distance between the permanent magnet and the display screen during magnetic fluid adsorption. This provides crucial structural design parameters for magnetic fluid displays. Building upon this foundation, the research further proposed a control scheme for the magnetohydrodynamic digital clock and successfully fabricated a prototype device. In addition, the methodology used in this study enabled the display of the Chinese character “horse” as a magnetohydrodynamic pattern. This study not only validates the feasibility of applying magnetic fluids and permanent magnets in the field of magnetohydrodynamic displays but also provides novel insights and practical references for advancing magnetohydrodynamic display technology through the determination of key parameters and display scheme design.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"62 1","pages":"1-8"},"PeriodicalIF":1.9,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145847836","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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