IEEE Transactions on Magnetics最新文献

{"title":"Tuning the Curie Temperature of Fe3O4 to Achieve Automated Magnetic Hyperthermia","authors":"Kabir S. Suraj;Gen Tatara;Hiroshi Katayama-Yoshida;M. Hussein N. Assadi","doi":"10.1109/TMAG.2025.3560645","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3560645","url":null,"abstract":"We examine the impact of samarium doping on the Curie temperature (<inline-formula> <tex-math>$T_{c}$ </tex-math></inline-formula>) of magnetite through density functional theory (DFT) calculations. Upon calculating the total energies of the different spin orientations among the cations in Fe 3O 4:Sm, we realized that the Sm atom prefers to substitute an Fe from the octahedral site with a spin opposing that of the atom it replaces. Our results show that Sm doping weakens the ferrimagnetic J coupling between the octahedral and tetrahedral Fe atoms. As a result, the normalized magnetization profile across a broad temperature range shows that the samarium-doped compound (Fe3O4:Sm) has a <inline-formula> <tex-math>$T_{c}$ </tex-math></inline-formula> of approximately 319 K, which aligns well with the target range for self-regulated magnetic nanoparticle hyperthermia (MNH) applications. Furthermore, we demonstrated that Sm doping in magnetite with high electron concentrations of <inline-formula> <tex-math>$10^{22} mathrm{~cm}^{-3}$ </tex-math></inline-formula> and <inline-formula> <tex-math>$10^{23} mathrm{~cm}^{-3}$ </tex-math></inline-formula> almost nearly preserves the Hall coefficient (<inline-formula> <tex-math>$R_{H}$ </tex-math></inline-formula>), implying that Fe3O4:Sm can be synthesized without significantly altering magnetite’s ability for tumor tissue identification based on the Hall effect.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"61 6","pages":"1-5"},"PeriodicalIF":2.1,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144170998","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}

{"title":"Low Torque Ripple and High Torque Trapezoidal Permanent Magnet Bi-Directional Magnetic Field Modulation Motor by Magnetomotive-Force-Oriented Design","authors":"Deyang Fan;Hongzuo Tian;Xiaoyong Zhu;Wu Shan;Zixuan Xiang","doi":"10.1109/TMAG.2025.3561168","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3561168","url":null,"abstract":"In this article, in order to suppress torque ripple and enhance output torque for bi-directional magnetic field modulation (BD-MFM) motors, a novel trapezoidal PM bi-directional magnetic field modulation (TMD-MFM) motor is proposed and designed from the perspective of magnetomotive-force (MMF)-oriented design. First, the relationship between MMF, airgap magnetic flux density, and torque is explained based on the magnetic field modulation principle of BD-MFM motors. Then, the contribution of PM airgap flux density harmonics to cogging torque is calculated using Maxwell’s tensor method, and a harmonic torque contribution coefficient is defined to compare the torque contribution of the PM airgap flux density harmonics. Based on the above, the important PM airgap flux density harmonics are selected. In addition, by the design of PM directional arrangement, trapezoidal PM, and trapezoidal magnetic barrier from the perspective of MMF, an MMF-oriented design of the airgap flux density harmonics can be achieved. Finally, the electromagnetic performance of the proposed TBD-MFM motor is compared in detail. It is demonstrated that the proposed TBD-MFM motor achieves higher output torque and lower torque ripple, thereby verifying the effectiveness of the MMF-based design method.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"61 9","pages":"1-6"},"PeriodicalIF":1.9,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144909265","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}

{"title":"Magnetic Relaxation of Gd-Doped MnFe2O4 Nanoparticles for MR Effect and Heat Dissipation","authors":"Noboru Kataoka;Akihito Usui;Yuu Kusumoto;Hiroki Amano;Yuko Ichiyanagi","doi":"10.1109/TMAG.2025.3560485","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3560485","url":null,"abstract":"MnGdxFe2-xO4 nanoparticles (<inline-formula> <tex-math>${x} =0$ </tex-math></inline-formula>, 0.05, 0.10) encapsulated in amorphous SiO2 were prepared by doping with a small amount of Gd ions, and their magnetic relaxation and magnetic resonance (MR) effects were investigated. The samples were prepared by wet mixing of metal chlorides and sodium metasilicate solutions, and the particle size was controlled to 18 nm by adjusting the annealing temperature. <inline-formula> <tex-math>${T} _{1}$ </tex-math></inline-formula> and <inline-formula> <tex-math>${T} _{2}$ </tex-math></inline-formula> relaxation measurements were performed by spin-echo method and MR signals were measured. All samples showed a shortening effect of <inline-formula> <tex-math>${T} _{2}$ </tex-math></inline-formula> relaxation. These phenomena would be attributed to the strong effect of the magnetic moment of Gd, which has a maximum of seven unpaired electrons in the <inline-formula> <tex-math>$4{f}$ </tex-math></inline-formula> orbitals on the protons. A dominant shortening effect was also observed at <inline-formula> <tex-math>${T} _{1}$ </tex-math></inline-formula> signals. The same sample was examined to see if it would function as a reagent for hyperthermia treatment. Temperature rises in an ac magnetic field and in vitro experiments using human breast cancer cells were carried out. As a result, a superior hyperthermia effect was observed, and these samples are expected to be an agent with theranostic function in the future.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"61 9","pages":"1-5"},"PeriodicalIF":1.9,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144920394","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}

{"title":"Analysis of Inductive Angular Position Sensors With the Characteristic of Annular Sector Coils","authors":"Dan-Ping Xu;Silong Fang;Yi Zhao;Fanlin Zeng;Sang-Moon Hwang","doi":"10.1109/TMAG.2025.3559933","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3559933","url":null,"abstract":"More interest and attention have been given to the inductive angular position sensor (IAPS) because of its high accuracy, simplified integration, and low price in the electric drive system. Three models with different characteristics of coils were designed to study the effect of characteristic of coils to the performance and accuracy. Compared with Type A, three times the number of turns in the receiving coils were structured in Type B. And Type C had a doubled annular sector angle of both excitation coil and receiving coils compared with Type B. The models were analyzed based on the electromagnetic theory and the skin effect theory. The induced voltages were obtained after the magnetic simulation using the finite element method. The accuracies of three types were derived after signal processing of the induced voltages. Three prototypes were manufactured and subsequently tested to verify the simulation results.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"61 9","pages":"1-5"},"PeriodicalIF":1.9,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144909170","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}

{"title":"Quantifying the Impact of Arbitrary Magnetic Field Perturbation on the Write Error Rate of Spin-Orbit-Torque Random Access Memory","authors":"Xuejie Xie;Wenlong Yang;Hengan Zhou;Kejie Huang;Enlong Liu","doi":"10.1109/TMAG.2025.3559973","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3559973","url":null,"abstract":"Spin-orbit-torque (SOT) magnetic random access memory (MRAM) is an emerging nonvolatile memory technology that uses the SOT effect to switch the magnetization direction of magnetic storage elements. Compared with spin-transfer torque (STT) MRAM, SOT-MRAM exhibits a faster write speed and higher endurance, making it a promising candidate for next-generation high-performance embedded memory or cache applications. However, the magnetic storage characteristics of MRAM render it susceptible to perturbation from external magnetic fields. In this study, we systematically and quantitatively investigated the impact of an arbitrary magnetic field <inline-formula> <tex-math>$mu _{0}mathbf {H}_{text {arb}}$ </tex-math></inline-formula> orientation (<inline-formula> <tex-math>$theta $ </tex-math></inline-formula>, <inline-formula> <tex-math>$varphi $ </tex-math></inline-formula>) on the write error rate (WER) of SOT-MRAM based on the Fokker-Planck equation (FPE) method and elucidated the underlying physical mechanism of magnetic field direction sensitivity. The results indicate that variations in (<inline-formula> <tex-math>$theta $ </tex-math></inline-formula>, <inline-formula> <tex-math>$varphi $ </tex-math></inline-formula>) can lead to different degrees of shift in the WER-switching time curve, eventually causing fluctuations in the WER at a fixed write pulsewidth. This phenomenon originates from the modulation of the magnetization probability density distribution by the angle between <inline-formula> <tex-math>$mu _{0}mathbf {H}_{text {arb}}$ </tex-math></inline-formula> and magnetization vector m. This research provides crucial insights into the effect of <inline-formula> <tex-math>$mu _{0}mathbf {H}_{text {arb}}$ </tex-math></inline-formula> on the WER of SOT-MRAM and emphasizes the importance of parameter adjustments to enhance the magnetic immunity of WER to <inline-formula> <tex-math>$mu _{0}mathbf {H}_{text {arb}}$ </tex-math></inline-formula> for improved write reliability under complex operating conditions.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"61 6","pages":"1-5"},"PeriodicalIF":2.1,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144170873","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}

{"title":"Novel Zero-Sequence Current Excited Double-Sided Vernier Reluctance Linear Machine With High-Order-Harmonic Toroidal Winding","authors":"Zhenghao Li;Feifan Ni;Shuangxia Niu;Kwok Tong Chau","doi":"10.1109/TMAG.2025.3559173","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3559173","url":null,"abstract":"Double-sided vernier reluctance linear machine (DS-VRLM) is very suitable for long stroke applications, taking advantage of magnet-free design, eliminated magnetic pull, and high thrust force density. Aiming to eliminate extra dc coils in DS-VRLM, and further boost the thrust force density of it, a novel non-overlapped double-layer integrated toroidal winding design excited by zero-sequence current is proposed in this article. The key to achieving this is to utilize artificial arrangement of integrated toroidal winding to generate spatial high-order harmonic of magnetic field for higher pole pair number (PPN) and gear ratio to acquire enhanced thrust density. Meanwhile, thanks to the toroidal winding configuration, the integrated toroidal winding could make full use of working harmonics, contributing to enhanced winding factor.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"61 9","pages":"1-6"},"PeriodicalIF":1.9,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144909268","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}

{"title":"Dynamic Analysis and Validation of Superconducting Rotor With a Spoke Suspension Torque Tube","authors":"Jianqiao Xiao;Himalaya Rautela;Samith Sirimanna;Thanatheepan Balachandran;Kiruba Haran","doi":"10.1109/TMAG.2025.3559381","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3559381","url":null,"abstract":"A superconducting rotor with a spoke suspension system can achieve a high specific power of 40 kW/kg. The spokes act as a torque tube with strong thermal insulation, virtually eliminating the conductive heat transfer between the ambient-temperature drive shaft and the cryogenic rotor shell, where superconducting coils are mounted. However, since the spoke geometries differ from a solid torque tube, existing rotordynamic analytical models are not directly applicable. This article presents an analytical model for the dynamic behavior of the spoke system, validated through finite element (FE) analysis and experimental impact testing. The study is conducted through three aspects: analytical derivation of the spoke system resonant frequencies, 3-D FE modal verification using Comsol, and experimental validation through a ping test. The first six mode shapes and modal frequencies show minimal discrepancies among these methods. The calibrated FE model is then used to generate a Campbell diagram for rotordynamic analysis. This study provides a useful calibrated tool for predicting the dynamic behavior of the suspension system.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"61 9","pages":"1-5"},"PeriodicalIF":1.9,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144914126","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}

{"title":"Magnetic Anomaly Target Motion State Detection Method Based on 3-D Convolutional Neural Network","authors":"Hexuan Sun;Jing Qiu;Shuanglong Huang;Xinjie Zeng;Beibei Fan;Cong Cao","doi":"10.1109/TMAG.2025.3558926","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3558926","url":null,"abstract":"Magnetic anomaly detection (MAD) can be used to detect and track ferromagnetic targets in invisible environments. However, it is extremely challenging to calculate the target’s motion state information based on the passively detected magnetic field signals. To address this problem, we propose a magnetic anomaly target motion state detection method based on 3-D convolutional neural network (3D CNN). The method utilizes a magnetic field sensor array to collect and visualize magnetic signals based on a MAD model for moving targets. The processed magnetic field signals are imaged and then arranged in time sequence to generate a motion flow. After standardizing the images, they are input into the 3D CNN to detect and classify motion of interest. Experimental validation was performed using a semi-real dataset with 16 target movements of interest and a control group without target movements. The experimental results show that the accuracy of the proposed method can reach 0.9 on average, which can provide a theoretical basis and method reference for the motion state recognition of ferromagnetic targets.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"61 9","pages":"1-6"},"PeriodicalIF":1.9,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144914127","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}

{"title":"Development of a Tri-Axis Concentric Fluxgate Magnetometer With High Orthogonality and High Linearity","authors":"Truong-Han Nguyen;Jen-Tzong Jeng;Long-Vu Bui","doi":"10.1109/TMAG.2025.3558810","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3558810","url":null,"abstract":"This study fabricates and characterizes a concentric tri-axis fluxgate magnetometer. The vector magnetometer features a tubular soft flux chopper with a toroidal coil and three concentric pick-up coils. The Z-axis pick-up coil is positioned within the cavity of the flux chopper to minimize the sensor’s size. With the X- and Y-axis pick-up coils encircling the flux chopper and the Z-axis coil situated at the center, the three sensing axes are concentric, resulting in an overall size for the vector sensing coils of no more than <inline-formula> <tex-math>$10 times 15 times 15$ </tex-math></inline-formula> mm. The concentric coils ensure a single field point for the X, Y, and Z sensing axes while achieving high orthogonality. The achieved non-orthogonality errors are less than ±1°. A three-axis fluxgate driving circuit based on second harmonic detection and magnetic field feedback has also been developed to enhance linearity. The built circuit can generate an ac excitation signal and efficiently demodulate the three-axis outputs of the concentric fluxgate sensor, producing three separate dc voltage signals that are proportional to the external quasi-static magnetic field. With feedback, the average non-linearity is 0.1% within the <inline-formula> <tex-math>$pm 60 ; mu $ </tex-math></inline-formula>T range. The proposed design concept is valuable for developing a compact and sensitive vector magnetometer suitable for precise geomagnetic measurements.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"61 9","pages":"1-5"},"PeriodicalIF":1.9,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144909212","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}

{"title":"An Improved Optimization Method Combining TO and Expertise in Permanent Magnet Synchronous Machine","authors":"Xiaoyu Liang;Mingqiao Wang;Yong Liu;Ping Zheng;Wanquan Li;Yi Sui","doi":"10.1109/TMAG.2025.3558742","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3558742","url":null,"abstract":"In addition to the support of permanent magnet synchronous machine (PMSM) design theory, the advanced structural optimization methods are needed to achieve PMSMs with high performance and their high-efficiency design process. Structural optimization is mainly divided into parameter optimization (PO) and topology optimization (TO). In order to further improve the efficiency of optimization design and PMSM performance, the professional electromagnetic theories are used to improve the design process based on the TO method of generating topology with high freedom. First, the advantages and disadvantages of TO method were summarized, and its corresponding mechanism and improvement methods were analyzed. By providing the evolution process of the new TO as an example, the improved optimization method of topology based on TO is demonstrated for improving torque quality. By utilizing methods, such as extracting high-performance substructures, adjusting optimization sequences, and improving data-driven models, the design efficiency has been improved. Finally, compared with conventional PMSM, the average torque and torque quality of improved topology by the proposed method have been significantly enhanced. The effectiveness of the improved optimization method of topology has been verified by finite element analysis (FEA) in PMSM.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"61 9","pages":"1-6"},"PeriodicalIF":1.9,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144909323","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}