IEEE Transactions on Magnetics最新文献

{"title":"Investigation of the Relationship Between the Velocity of Magnetic Domain Wall and Magnetic Barkhausen Noise Using Classic + NL Algorithm","authors":"Xinrong Wen;Peng Li;Xinyang Han;Bin Wu;Yujue Wang;Xiucheng Liu","doi":"10.1109/TMAG.2025.3582763","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3582763","url":null,"abstract":"Domain wall (DW) velocity is a key parameter for understanding magnetic domain dynamics in ferromagnetic materials. However, traditional algorithms for DW velocity extraction often suffer from inaccuracies, limiting the precise correlation between microscopic domain dynamics and macroscopic magnetic Barkhausen noise (MBN). In this study, we quantitatively compare the accuracy of multiple optical flow algorithms in DW velocity extraction. First, we establish rigorous error metrics to evaluate optical flow performance. We then optimize the parameters of three optical flow algorithms—Horn–Schunck (H–S), Brox, and Classic + NL—and demonstrate that Classic + NL outperforms the others in both standard test images and experimental domain motion images. Furthermore, we validate the Classic + NL algorithm’s reliability through correlation analysis between the DW velocity and MBN envelope. This framework provides a robust foundation for linking microscopic DW motion with macroscopic MBN responses, advancing the precision of domain dynamics characterization.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"61 8","pages":"1-11"},"PeriodicalIF":2.1,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144716197","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":"A Magnetic Moment Calculation Method Based on Magnetic Gradient Tensor Eigenvalues","authors":"Sansheng Wang;Shiyao Wang;Fan Liu;Yiyuan Wang;Xiaoping Jin","doi":"10.1109/TMAG.2025.3582039","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3582039","url":null,"abstract":"Understanding the magnetic characteristics of a target is essential for magnetic anomaly detection (MAD), and the magnetic moment is a fundamental and important physical quantity for describing these characteristics. Measurement of the magnetic moment is important for target detection, classification, and localization. In this article, we propose a method of calculating the magnetic moment using magnetic gradient tensor (MGT) eigenvalues. We first derived equations for inverting the magnetic moment from MGT eigenvalues and eigenvectors. We then conducted simulations for different conditions of the target pose, target distance, and relative position, and obtained the applicable conditions of the method. We finally conducted experiments using a full MGT sensor developed by our team. The experimental results were consistent with the simulation results. Under the applicable conditions, the calculation error of the magnetic moment magnitude was <inline-formula> <tex-math>$le 0.5$ </tex-math></inline-formula> Am2 and the direction error was <inline-formula> <tex-math>$le 5^{circ }$ </tex-math></inline-formula>. However, the method places restrictions on the pose of the target relative to the MGT sensor, which introduces obvious limitations. Therefore, we created a rotation-averaged error correction algorithm that makes the method applicable to any target pose. The method is expected to be applied to the rough calibration of target magnetic moments and may be helpful to the identification of small magnetic targets.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"61 8","pages":"1-12"},"PeriodicalIF":2.1,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144716241","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":"Enhancing Core Loss Tracking Accuracy in Stator Cores: A Comparative Assessment of Static and Dynamic Jiles-Atherton Model Formulations","authors":"Leonardo Colombo;Avo Reinap;Pontus Fyhr;Mats Alaküla","doi":"10.1109/TMAG.2025.3581713","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3581713","url":null,"abstract":"In this article, a comparison between static and dynamic formulations of the Jiles-Atherton (JA) hysteresis model is presented. An assessment on the accuracy of core loss prediction and hysteretic loop reproduction of experimentally characterized stator cores is performed. The novelty in this work is found in the optimized JA parameter datasets describing all the hysteresis loops measured for each of the considered excitation frequencies ranging between 25 and 800 Hz: hysteresis loops with the same excitation frequency, having different maximum flux density values, are modeled using the same JA parameter set. The dynamic model is, then, compared to Bertotti’s model, and for laminated steel samples, it is better suited to estimate core losses at a wide range of test points.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"61 8","pages":"1-12"},"PeriodicalIF":2.1,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144716193","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":"Critical Exponent Study and Magnetocaloric Effect of Co₀.₃Zn₀.₇Fe₂O₄","authors":"Prabhu Rajagiri;Y. Srinivasa Reddy;S. Shanmukharao Samatham;M. Chandra Sekhar;Gowrinaidu Babbadi;Muralikrishna Patwari;Nataraju Gandla;T. Venkata Apparao","doi":"10.1109/TMAG.2025.3581199","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3581199","url":null,"abstract":"Magnetic, magnetocaloric, and universality class of Co0.3Zn0.7Fe2O4 (CZFO) is reported. It orders ferrimagnetically with dominant parallel-spin interactions inferred from the positive Weiss paramagnetic temperatures. The extracted critical exponents and critical temperatures through modified Arrott plot (Kouvel-Fisher) methods are <inline-formula> <tex-math>$T_{mathrm {c}} = 263.96$ </tex-math></inline-formula> K (263.81 K), <inline-formula> <tex-math>$beta = 0.353$ </tex-math></inline-formula> (0.392), <inline-formula> <tex-math>$gamma = 1.325$ </tex-math></inline-formula> (1.345), and <inline-formula> <tex-math>$delta = 4.754$ </tex-math></inline-formula> (4.431). The exponents suggest a 3-D Heisenberg universality class along with admixture of dominant-short- and weak-long-range interactions inferred from exchange interaction function <inline-formula> <tex-math>$J(r) sim 1/r^{4.902}$ </tex-math></inline-formula> with spin-interaction range <inline-formula> <tex-math>$sigma $ </tex-math></inline-formula> (=1.902) nearly equal to 2. In addition, mean-field theory plots, scaled renormalized magnetization (m) and magnetic field (h), and m2 versus h/m confirm the self-consistency of the exponent and a second-order phase transition. Magnetocaloric effect (MCE) analysis reveals <inline-formula> <tex-math>$Delta S_{mathrm {mag,max}}$ </tex-math></inline-formula> of 2 J <inline-formula> <tex-math>$cdot $ </tex-math></inline-formula> <inline-formula> <tex-math>$kg^{-1}~cdot $ </tex-math></inline-formula> K−1 and a relative cooling power (RCP) of about 87 J <inline-formula> <tex-math>$cdot $ </tex-math></inline-formula> kg−1 in <inline-formula> <tex-math>$Delta H = 50$ </tex-math></inline-formula> kOe.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"61 8","pages":"1-10"},"PeriodicalIF":2.1,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144716251","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":"Characterization of spatial homogeneous regions in tissues with concordex.","authors":"Kayla C Jackson, A Sina Booeshaghi, Ángel Gálvez-Merchán, Lambda Moses, Tara Chari, Alexandra Kim, Orhan Hosten-Mittermaier, Lior Pachter","doi":"10.1101/2023.06.28.546949","DOIUrl":"10.1101/2023.06.28.546949","url":null,"abstract":"<p><p>The rapid advancement of spatially resolved transcriptomics (SRT) technologies has facilitated exploration of how gene expression varies across tissues. However, identifying spatially variable genes remains challenging due to confounding variation introduced by the spatial distribution of cell types. We introduce a new approach to identifying spatial domains that are homogeneous with respect to cell-type composition that facilitates the decomposition of gene expression patterns by cell-type and spatial variation. Our method, called concordex, is efficient and effective across technological platforms and tissue types, and using several biological datasets we show that it can be used to identify genes with subtle variation patterns that are missed when considering only cell-type variation, or spatial variation, alone. The concordex tool is freely available at https://github.com/pachterlab/concordexR.</p>","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"24 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11275758/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84732967","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}

{"title":"A Novel OrbiTran Magnetically Geared Rotating Electrical Machine","authors":"Oleg Molokanov","doi":"10.1109/TMAG.2025.3580223","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3580223","url":null,"abstract":"This article presents a novel electrical machine topology with a built-in magnetic gear (MG), combining concepts from cycloidal MGs and rolling-rotor machines (RMMs). It enables electromechanical conversion in both motor and generator modes. To overcome the complex rotation typically associated with cycloidal gears, the high-speed (HS) and low-speed (LS) rotors are mechanically decoupled. The HS rotor performs translational motion along a small orbit, which inspired the name “OrbiTran.” A 2-D FEM model with a gear ratio of 60 was developed, demonstrating a torque density of 114 kN<inline-formula> <tex-math>$cdot $ </tex-math></inline-formula>m/m3 under relatively low thermal load on the stator windings, which typically corresponds to natural convection cooling. It was also demonstrated that the proposed machine can continuously operate at maximum torque density with negligible torque ripples. Since the component of the machine responsible for electromechanical conversion relies on reluctance torque, and PMs are naturally shielded from armature magnetic fields, the proposed device is expected to exhibit a high degree of fault tolerance. Despite its many advantages, proposed topology still inherits significant radial imbalances from the cycloidal MG, and the RMM it is based on.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"61 8","pages":"1-11"},"PeriodicalIF":2.1,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144716240","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":"Mutual Inductance of Multilayer Spiral-Inductor Clusters for Small-Form-Factor Wireless Power Transfer (μWPT)","authors":"Joshua S. Benjestorf;Julio V. Urbina;Akhlesh Lakhtakia","doi":"10.1109/TMAG.2025.3579931","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3579931","url":null,"abstract":"Spiral inductors are commonly used in wireless power transfer (WPT) systems due to their simplicity and low cost, but their large physical size poses challenges for <inline-formula> <tex-math>$mu $ </tex-math></inline-formula>WPT systems (i.e., WPT systems with small form factors). To address these challenges, multilayer spiral-inductor clusters (MSICs) are employed to increase the mutual inductance between the transmitting and receiving couplers for acceptably high power-transfer efficiency. This article uses the Neumann formula, first, to derive an exact analytical expression for the equivalent inductance <inline-formula> <tex-math>$L_{N}^{mathrm { Eq1}}$ </tex-math></inline-formula> of an MSIC of N layers and, second, to conceptualize a mutual inductance <inline-formula> <tex-math>$M_{N}^{dy}(g)$ </tex-math></inline-formula> between two MSICs that are separated by an air gap g and derive an exact analytical expression for it. These novel expressions were verified experimentally within 1% margin of error and can be easily applied to design <inline-formula> <tex-math>$mu $ </tex-math></inline-formula>WPT systems.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"61 8","pages":"1-10"},"PeriodicalIF":2.1,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144716192","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":"Manipulating the FMR Frequency of YIG Nanostrips With Exchange Bias","authors":"Wen Huang;Yong Ren;Xiaoyu Li;Min Chen;Yan Zhang;Fang Xu;Guixiang Liu;Bo Dai","doi":"10.1109/TMAG.2025.3578784","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3578784","url":null,"abstract":"Microwave ferrite devices are now widely utilized across various scenarios, often requiring the application of an external bias field to manipulate their operational frequency. As ferrite devices continue to shrink in size, there is increasing interest in leveraging the exchange bias effect to regulate frequency within a smaller volume. In the study, our research focuses on exploring an optimum method that manipulates the ferromagnetic resonance (FMR) frequency of thin yttrium iron garnet (YIG)/IrMn bilayer nanostrips. Through theoretical analysis and simulations, our model demonstrates the successful adjustability of YIG film’s FMR frequency from 0 to 30 GHz, which offers valuable insights for designing miniaturized, frequency-adjustable microwave ferrite devices.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"61 8","pages":"1-8"},"PeriodicalIF":2.1,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144716243","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":"Influence of Grain Boundary Diffusion on the Coercivity, Thermal Stability, and Magnetization Reversal of Sintered Nd–Fe–B Permanent Magnets","authors":"Suo Bai;Yanrui Shi;Bangchen Li;Jizhong Zhao;Yongfeng Li;Zhubai Li;Qian Zhao;Shilin Luo","doi":"10.1109/TMAG.2025.3578188","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3578188","url":null,"abstract":"Grain boundary diffusion considerably enhances the coercivity of sintered Nd–Fe–B permanent magnets and optimizes their microstructures. Herein, we fabricated these magnets with a nominal composition of Nd30.25Fe68.22M0.59B0.94 (M represents Cu, Co, Zr, Ga, and Al) via powder metallurgy. Terbium fluoride powder served as the diffusion source in grain boundary diffusion. After the diffusion, the coercivity of the magnets substantially increased. Moreover, the temperature coefficient of coercivity (<inline-formula> <tex-math>$beta $ </tex-math></inline-formula>) considerably improved in the temperature range of <inline-formula> <tex-math>$25~^{circ }$ </tex-math></inline-formula>C–<inline-formula> <tex-math>$150~^{circ }$ </tex-math></inline-formula>C. The considerable enhancement in coercivity and its <inline-formula> <tex-math>$beta $ </tex-math></inline-formula> is attributed to the formation of Tb-rich (Nd, Tb)2Fe14B phases with high magnetocrystalline anisotropy in the outer layers of the main phase grains. This optimizes the grain boundary structure and reduces surface defects of the main phase grains during grain boundary diffusion, increasing the coercivity, weakening the exchange coupling effect, and suppressing magnetization reversal. The recoil loops and thermal activation reflect this suppression, possibly owing to the exchange coupling effect among the Nd2Fe14B main phase grains or the (Nd, Tb)2Fe14B main phase grains with a core-shell structure as well as between the core and shell of the (Nd, Tb)2Fe14B main phase grains. These synergistic effects enhance the nucleation field for reverse domains on the main phase surface and reduce the activation volume. Consequently, coercivity is enhanced, effectively suppressing magnetization reversal and thermal fluctuations. This ensures high remanence, thermal stability, and demagnetization resistance in the Nd–Fe–B permanent magnets, thereby enhancing the reliability and efficiency of permanent-magnet motors in long-term operation.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"61 7","pages":"1-7"},"PeriodicalIF":2.1,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144536457","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":"Topology Optimization of Annular Lorentz Force Actuator for Non-Contact Annular Electromagnetic Stabilized Spacecraft","authors":"Mingxuan Song;He Liao;Zijie Wu;Haoxiang Yuan","doi":"10.1109/TMAG.2025.3578529","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3578529","url":null,"abstract":"As the core actuator to ensure the high-precision attitude control of the non-contact annular electromagnetic stabilized spacecraft, the annular Lorentz force actuator (ALFC) plays a pivotal role in control system due to its advantages of rapid response and high accuracy. This study proposes a topology optimization to transcend the traditional design paradigms. First, a solid isotropic material with penalization (SIMP)-based optimization model is constructed, which incorporating magnetic flux density distribution into the objective function and establishing a material interpolation model for annular magnetic circuits and coil configurations. Second, the method of moving asymptotes (MMAs) algorithm is employed to solve the non-convex optimization problem. Finally, through finite element simulations, the optimization results are quantitatively assessed, ultimately identifying a novel ALFC structure that satisfies both precision and intensity requirements for engineering applications, which provides a novel design paradigm for non-contact annular electromagnetic stabilized spacecraft.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"61 8","pages":"1-8"},"PeriodicalIF":2.1,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144716347","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}