Pub Date : 2025-12-16DOI: 10.1109/TMAG.2025.3644349
Junfeng Gao;Xinhua Wang;Tao Sun;Zisheng Guo;Lin Yang;Amjad Ali;Yuxia Han
To overcome the limitations of conventional non-destructive testing (NDT) methods for pipelines operating under extreme conditions, such as high temperatures and cryogenic environments, a novel differential magnetic field coil sensor has been designed. This sensor reduces interference from the excitation magnetic field on detection signals, thereby improving the signal-to-noise ratio (SNR). This coil sensor employs harmonic magnetic field excitation (HMFE), utilizing a high-sensitivity pickup coil to receive magnetic field signals. The HMFE technique effectively enhances magnetic field penetration depth by modulating the pipeline's magnetic permeability. Both finite element simulations and experiments demonstrate that HMFE improves the distribution of induced currents within the pipe body, increasing detection depth and accuracy. The proposed differential magnetic field coil sensor enables non-contact inspection of insulated pipelines. Under HMFE, the detection signal contains rich defect characteristic signals. It can effectively detect typical pipeline defects beneath 100 mm thick insulation layers, capable of identifying corrosion pits as small as 3 cm2 at a depth of 2 mm and through-holes with diameters as small as 10 mm. It also demonstrates excellent detection performance for circumferential scratches on pipelines. Even when defects are oriented at a 45° angle relative to the inspection position, the method maintains reliable identification capabilities.
{"title":"A New Sensor for Harmonic Magnetic Field Detection in Pipelines Without Removing Insulation Layer","authors":"Junfeng Gao;Xinhua Wang;Tao Sun;Zisheng Guo;Lin Yang;Amjad Ali;Yuxia Han","doi":"10.1109/TMAG.2025.3644349","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3644349","url":null,"abstract":"To overcome the limitations of conventional non-destructive testing (NDT) methods for pipelines operating under extreme conditions, such as high temperatures and cryogenic environments, a novel differential magnetic field coil sensor has been designed. This sensor reduces interference from the excitation magnetic field on detection signals, thereby improving the signal-to-noise ratio (SNR). This coil sensor employs harmonic magnetic field excitation (HMFE), utilizing a high-sensitivity pickup coil to receive magnetic field signals. The HMFE technique effectively enhances magnetic field penetration depth by modulating the pipeline's magnetic permeability. Both finite element simulations and experiments demonstrate that HMFE improves the distribution of induced currents within the pipe body, increasing detection depth and accuracy. The proposed differential magnetic field coil sensor enables non-contact inspection of insulated pipelines. Under HMFE, the detection signal contains rich defect characteristic signals. It can effectively detect typical pipeline defects beneath 100 mm thick insulation layers, capable of identifying corrosion pits as small as 3 cm2 at a depth of 2 mm and through-holes with diameters as small as 10 mm. It also demonstrates excellent detection performance for circumferential scratches on pipelines. Even when defects are oriented at a 45° angle relative to the inspection position, the method maintains reliable identification capabilities.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"62 2","pages":"1-11"},"PeriodicalIF":1.9,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146082237","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 : 2025-12-16DOI: 10.1109/TMAG.2025.3644394
Linhai Hu;Yun Xu;Haoran Lv;Chenyu Zhao
Multi-target transcranial magnetic stimulation (TMS) overcomes the limitations of single-coil physical movement by enabling collaborative stimulation with multiple coils, which has become a key trend in neural modulation research. However, however, current regulation and synchronization challenges arising from multi-coil coupling remain unresolved. This article takes a three-coil coupled system as the research object and proposes a complete solution from underlying modeling to experimental verification: using Kirchhoff’s laws, transient expressions for capacitor voltage and coil current under coupling are derived, a circuit-electromagnetic field coupled model is established, and an accurate expression of the current waveform is provided. This approach determines the capacitance values and precise voltages for different modes and achieves improved synchronization of coil current waveforms by combining capacitor switching and voltage regulation. Circuit simulation verification using Simulink shows that the cosine similarity of current synchronization reaches over 0.9. Further verification is conducted through circuit experiments, and the magnetic field distribution driven by current waveforms is simulated in COMSOL, successfully achieving effective stimulation with electric field strength greater than 100 V/m and mode switching under Mode 1 (1.3 cm shallow double targets) and Mode 2 (2.2 cm deep single target). The research indicates that precise control based on circuit-coupled modeling can effectively enhance the current synchronization of multi-coil coupled system, providing a theoretical basis and engineering practice paradigm for the clinical application of multi-target switching TMS.
{"title":"A Multi-Target Transcranial Magnetic Stimulation System With Coupled Modeling Control","authors":"Linhai Hu;Yun Xu;Haoran Lv;Chenyu Zhao","doi":"10.1109/TMAG.2025.3644394","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3644394","url":null,"abstract":"Multi-target transcranial magnetic stimulation (TMS) overcomes the limitations of single-coil physical movement by enabling collaborative stimulation with multiple coils, which has become a key trend in neural modulation research. However, however, current regulation and synchronization challenges arising from multi-coil coupling remain unresolved. This article takes a three-coil coupled system as the research object and proposes a complete solution from underlying modeling to experimental verification: using Kirchhoff’s laws, transient expressions for capacitor voltage and coil current under coupling are derived, a circuit-electromagnetic field coupled model is established, and an accurate expression of the current waveform is provided. This approach determines the capacitance values and precise voltages for different modes and achieves improved synchronization of coil current waveforms by combining capacitor switching and voltage regulation. Circuit simulation verification using Simulink shows that the cosine similarity of current synchronization reaches over 0.9. Further verification is conducted through circuit experiments, and the magnetic field distribution driven by current waveforms is simulated in COMSOL, successfully achieving effective stimulation with electric field strength greater than 100 V/m and mode switching under Mode 1 (1.3 cm shallow double targets) and Mode 2 (2.2 cm deep single target). The research indicates that precise control based on circuit-coupled modeling can effectively enhance the current synchronization of multi-coil coupled system, providing a theoretical basis and engineering practice paradigm for the clinical application of multi-target switching TMS.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"62 2","pages":"1-6"},"PeriodicalIF":1.9,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146082305","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}
This article presents a degradation model that characterizes the local magnetization properties of non-oriented electrical steel, which takes into account the effects of wire electrical discharge machining (WEDM) and stress relief annealing. The innovation of the presented model lies in its minimal requirement of the measured sample data and the capability of predicting the magnetization properties of narrow structures where degraded areas overlap. In particular, only a single test sample along with original material data is needed to obtain the model coefficients for non-annealed steel sheets. Such a low demand for the measured source data is attributed to the accurate model setup, combined with the residual stress and the limited number of model coefficients. The presented model is fit and applied to the test samples, which are cut from three grades of steel sheets using the WEDM method, both with and without the annealing process. To validate the effectiveness of the proposed model and assess the manufacturing impact on real motors, two synchronous reluctance machines are fabricated with WEDM and annealing methods and measured. Compared to the calculated results using original material data, the static torque calculation error is reduced from 6.9% and 5.6% to 0.8% and 1.4% with the proposed material degradation model.
{"title":"Degradation Model on B–H Curves of Non-Oriented Electrical Steel Considering Wire Electrical Discharge Machining and Annealing","authors":"Youhao Zhang;Kejia Zhang;Dan Shi;Yunchong Wang;Shun Cai;Wenzhi Chen;Jian-Xin Shen","doi":"10.1109/TMAG.2025.3642539","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3642539","url":null,"abstract":"This article presents a degradation model that characterizes the local magnetization properties of non-oriented electrical steel, which takes into account the effects of wire electrical discharge machining (WEDM) and stress relief annealing. The innovation of the presented model lies in its minimal requirement of the measured sample data and the capability of predicting the magnetization properties of narrow structures where degraded areas overlap. In particular, only a single test sample along with original material data is needed to obtain the model coefficients for non-annealed steel sheets. Such a low demand for the measured source data is attributed to the accurate model setup, combined with the residual stress and the limited number of model coefficients. The presented model is fit and applied to the test samples, which are cut from three grades of steel sheets using the WEDM method, both with and without the annealing process. To validate the effectiveness of the proposed model and assess the manufacturing impact on real motors, two synchronous reluctance machines are fabricated with WEDM and annealing methods and measured. Compared to the calculated results using original material data, the static torque calculation error is reduced from 6.9% and 5.6% to 0.8% and 1.4% with the proposed material degradation model.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"62 2","pages":"1-10"},"PeriodicalIF":1.9,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146082292","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 : 2025-12-05DOI: 10.1109/TMAG.2025.3640967
Jéssica Kamilly Pereira França;Aline Alves de Freitas;Hellen Barros Lopes Silva;Maurício Silva Lopes;Hudson Antonio Dias Teixeira;Walajhone Oliveira Pereira;Alan Silva de Menezes;Adenilson Oliveira Dos Santos;Luzeli Moreira da Silva
Multiphase alloys with sequential long-range magnetic order represent an intriguing approach to overcoming an intrinsic limitation of single-phase magnetocaloric materials by broadening the operational temperature window and enhancing thermal coupling between phases. In this study, we investigate a dysprosium–platinum–indium (Dy–Pt–In) alloy with a nominal composition of 35 wt% Dy, 41 wt% Pt, and 24 wt% In, synthesized by arc melting and characterized in terms of its structural, microstructural, magnetic, and magnetocaloric properties. Rietveld refinement of X-ray diffraction data, combined with scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) analyses, revealed a multiphase alloy composed of a DyPtIn, DyPt2In, and dysprosium–platinum (DyPt) intermetallic phases. The alloy exhibit three magnetic transitions: two successive ferromagnetic (FM) transitions at 32.5 and 23.0 K, and a field-dependent antiferromagnetic-like transition at 7.5 K, which together sustain an nearly constant adiabatic temperature change of ~2.1 K across a broad temperature range (2.5–57 K) and a maximum magnetic entropy change of ~6.3 J/kg·K for a field variation of 50 kOe. The results demonstrate the potential of Dy–Pt–In multiphase systems to extend the working temperature span and enhance the performance of cryogenic magnetic refrigeration (MR) applications.
{"title":"Magnetic Properties and Magnetocaloric Performance in a Dy–Pt–In Multiphase Alloy","authors":"Jéssica Kamilly Pereira França;Aline Alves de Freitas;Hellen Barros Lopes Silva;Maurício Silva Lopes;Hudson Antonio Dias Teixeira;Walajhone Oliveira Pereira;Alan Silva de Menezes;Adenilson Oliveira Dos Santos;Luzeli Moreira da Silva","doi":"10.1109/TMAG.2025.3640967","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3640967","url":null,"abstract":"Multiphase alloys with sequential long-range magnetic order represent an intriguing approach to overcoming an intrinsic limitation of single-phase magnetocaloric materials by broadening the operational temperature window and enhancing thermal coupling between phases. In this study, we investigate a dysprosium–platinum–indium (Dy–Pt–In) alloy with a nominal composition of 35 wt% Dy, 41 wt% Pt, and 24 wt% In, synthesized by arc melting and characterized in terms of its structural, microstructural, magnetic, and magnetocaloric properties. Rietveld refinement of X-ray diffraction data, combined with scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) analyses, revealed a multiphase alloy composed of a DyPtIn, DyPt2In, and dysprosium–platinum (DyPt) intermetallic phases. The alloy exhibit three magnetic transitions: two successive ferromagnetic (FM) transitions at 32.5 and 23.0 K, and a field-dependent antiferromagnetic-like transition at 7.5 K, which together sustain an nearly constant adiabatic temperature change of ~2.1 K across a broad temperature range (2.5–57 K) and a maximum magnetic entropy change of ~6.3 J/kg·K for a field variation of 50 kOe. The results demonstrate the potential of Dy–Pt–In multiphase systems to extend the working temperature span and enhance the performance of cryogenic magnetic refrigeration (MR) applications.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"62 1","pages":"1-9"},"PeriodicalIF":1.9,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11278829","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145847823","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 : 2025-12-04DOI: 10.1109/TMAG.2025.3640177
Xuchao Zhang;Lei Ma;Chao Fan;Hongyun Liu;Yuanyuan Li;Jiting Li;Jian Li;Jiatai Wang
The wireless charging performance of coils inserted with Ni0.2Mn0.2Zn0.6Fe2O4 ferrite cores was investigated. Ni0.2Mn0.2Zn0.6Fe2O4 ferrites were prepared and sintered under different temperatures ($T_{mathrm{s}}$ ). The effects of $T_{mathrm{s}}$ on the crystal structure, phase composition, morphology, magnetic properties, and wireless charging performance were investigated. The X-ray diffraction (XRD) measurements reveal that there are two phases including an $alpha-mathrm{Fe}_2 mathrm{O}_3$ stray phase. As $T_{mathrm{s}}$ increasing from $700^{circ} mathrm{C}$ to $1100^{circ} mathrm{C}, alpha-mathrm{Fe}_2 mathrm{O}_3$ stray phase disappeared and formed a single spinel phase. The grain size and saturated magnetization ($M_{mathrm{s}}$ ) of ferrites also increase with $T_{mathrm{s}}$ , and the coercivity ($H_{mathrm{c}}$ ) decreases with $T_{mathrm{s}}$ . These are all correlated with the improvement of crystal properties and especially the elimination of $alpha-mathrm{Fe}_2 mathrm{O}_3$ stray phases. Wireless charging results show that the $1000^{circ} mathrm{C}$ sintered ferrite has the highest influence on the charging efficiency.
{"title":"Sintered Ni–Mn–Zn Ferrites With Changeable Magnetic Properties for Wireless Charging Application","authors":"Xuchao Zhang;Lei Ma;Chao Fan;Hongyun Liu;Yuanyuan Li;Jiting Li;Jian Li;Jiatai Wang","doi":"10.1109/TMAG.2025.3640177","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3640177","url":null,"abstract":"The wireless charging performance of coils inserted with Ni0.2Mn0.2Zn0.6Fe2O4 ferrite cores was investigated. Ni0.2Mn0.2Zn0.6Fe2O4 ferrites were prepared and sintered under different temperatures (<inline-formula> <tex-math>$T_{mathrm{s}}$ </tex-math></inline-formula>). The effects of <inline-formula> <tex-math>$T_{mathrm{s}}$ </tex-math></inline-formula> on the crystal structure, phase composition, morphology, magnetic properties, and wireless charging performance were investigated. The X-ray diffraction (XRD) measurements reveal that there are two phases including an <inline-formula> <tex-math>$alpha-mathrm{Fe}_2 mathrm{O}_3$ </tex-math></inline-formula> stray phase. As <inline-formula> <tex-math>$T_{mathrm{s}}$ </tex-math></inline-formula> increasing from <inline-formula> <tex-math>$700^{circ} mathrm{C}$ </tex-math></inline-formula> to <inline-formula> <tex-math>$1100^{circ} mathrm{C}, alpha-mathrm{Fe}_2 mathrm{O}_3$ </tex-math></inline-formula> stray phase disappeared and formed a single spinel phase. The grain size and saturated magnetization (<inline-formula> <tex-math>$M_{mathrm{s}}$ </tex-math></inline-formula>) of ferrites also increase with <inline-formula> <tex-math>$T_{mathrm{s}}$ </tex-math></inline-formula>, and the coercivity (<inline-formula> <tex-math>$H_{mathrm{c}}$ </tex-math></inline-formula>) decreases with <inline-formula> <tex-math>$T_{mathrm{s}}$ </tex-math></inline-formula>. These are all correlated with the improvement of crystal properties and especially the elimination of <inline-formula> <tex-math>$alpha-mathrm{Fe}_2 mathrm{O}_3$ </tex-math></inline-formula> stray phases. Wireless charging results show that the <inline-formula> <tex-math>$1000^{circ} mathrm{C}$ </tex-math></inline-formula> sintered ferrite has the highest influence on the charging efficiency.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"62 1","pages":"1-6"},"PeriodicalIF":1.9,"publicationDate":"2025-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145847827","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 : 2025-12-04DOI: 10.1109/TMAG.2025.3640276
Andreas Grendas;Michael Wiesheu;Sebastian Schöps;Benjamin Marussig
Adaptive refinement in isogeometric analysis (IGA) provides a flexible way to improve accuracy while controlling computational effort. This work builds on spline basis functions, used both for geometry representation and numerical discretization, and extends them with truncated hierarchical B-splines (THB-splines) to enable local mesh refinement with structured flexibility. To support standard finite element assembly, multi-level Bézier extraction is applied, allowing THB-spline bases to be expressed in terms of local Bernstein polynomials. Refinement is driven by a least-squares a posteriori error estimator integrated into the spline discretization. A unified formulation is presented that couples this estimator with the harmonic mortaring of the rotor–stator, ensuring consistency of the interface while guiding refinement in the coupled problem. The method is demonstrated with 2-D magnetostatic simulations involving a permanent magnet synchronous machine (PMSM).
{"title":"Adaptive Isogeometric Analysis With THB-Splines and Multi-Level Bézier Extraction for Coupled Magnetostatics","authors":"Andreas Grendas;Michael Wiesheu;Sebastian Schöps;Benjamin Marussig","doi":"10.1109/TMAG.2025.3640276","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3640276","url":null,"abstract":"Adaptive refinement in isogeometric analysis (IGA) provides a flexible way to improve accuracy while controlling computational effort. This work builds on spline basis functions, used both for geometry representation and numerical discretization, and extends them with truncated hierarchical B-splines (THB-splines) to enable local mesh refinement with structured flexibility. To support standard finite element assembly, multi-level Bézier extraction is applied, allowing THB-spline bases to be expressed in terms of local Bernstein polynomials. Refinement is driven by a least-squares a posteriori error estimator integrated into the spline discretization. A unified formulation is presented that couples this estimator with the harmonic mortaring of the rotor–stator, ensuring consistency of the interface while guiding refinement in the coupled problem. The method is demonstrated with 2-D magnetostatic simulations involving a permanent magnet synchronous machine (PMSM).","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"62 1","pages":"1-11"},"PeriodicalIF":1.9,"publicationDate":"2025-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11278434","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145847834","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}
We present a method for modeling arbitrarily shaped anisotropic magnetoelectric objects immersed in a homogeneous isotropic medium and exposed to an arbitrary electric field. The method requires the discretization of only boundary layers and solves the problem directly, without transforming it into an isotropic one. We investigate anisotropic magnetoelectric materials of the Tellegen type, characterized by nine parameters for each of the permittivity, permeability, and coupling matrices. Results are compared against an analytical solution for the case of a magnetoelectric anisotropic sphere placed in air and exposed to a uniform electric field. We achieve a total normalized root mean square error (NRMSE) for the electric field below 0.1% and below 0.2% for the magnetic field. With a slight modification, the method can be applied to magnetoelectric materials exposed to a magnetic or combined electric and magnetic fields.
{"title":"Boundary Element Modeling of Magnetoelectric Anisotropic Materials","authors":"Bojana Petković;Marek Ziolkowski;Jens Haueisen;Hannes Toepfer","doi":"10.1109/TMAG.2025.3639930","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3639930","url":null,"abstract":"We present a method for modeling arbitrarily shaped anisotropic magnetoelectric objects immersed in a homogeneous isotropic medium and exposed to an arbitrary electric field. The method requires the discretization of only boundary layers and solves the problem directly, without transforming it into an isotropic one. We investigate anisotropic magnetoelectric materials of the Tellegen type, characterized by nine parameters for each of the permittivity, permeability, and coupling matrices. Results are compared against an analytical solution for the case of a magnetoelectric anisotropic sphere placed in air and exposed to a uniform electric field. We achieve a total normalized root mean square error (NRMSE) for the electric field below 0.1% and below 0.2% for the magnetic field. With a slight modification, the method can be applied to magnetoelectric materials exposed to a magnetic or combined electric and magnetic fields.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"62 1","pages":"1-9"},"PeriodicalIF":1.9,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145847825","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}
We propose an oscillation-controlled magnetic sensing (OCMS) circuit architecture using MgO-based magnetic tunnel junctions (MTJs) and investigate its magnetic field response characteristics. Compared to the conventional sensing-current method commonly used in hard disk drive (HDD) read heads and magnetic sensors, the OCMS approach achieves an output voltage up to 8.1 times higher. Notably, a large oscillation output of 952 mVpp is obtained with sensing current as low as 0.4–0.6 mA flowing through the MTJ. The measured output response shows strong agreement with the TopSPICE simulations, which further predict output voltages exceeding 10 Vpp at a sensing current of 0.82 mA and an operation frequency of 10 MHz. These results demonstrate that the OCMS method enables high-output, low-power, and high-frequency magnetic sensing, offering a promising solution for the next-generation spintronic sensor technologies.
{"title":"Magnetic Sensing via Oscillation Control in MgO-Based Magnetic Tunnel Junctions","authors":"Mizuki Wakamoto;Yuto Shibata;Mizuki Matsuzaka;Gang Xiao;Hideo Kaiju","doi":"10.1109/TMAG.2025.3640104","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3640104","url":null,"abstract":"We propose an oscillation-controlled magnetic sensing (OCMS) circuit architecture using MgO-based magnetic tunnel junctions (MTJs) and investigate its magnetic field response characteristics. Compared to the conventional sensing-current method commonly used in hard disk drive (HDD) read heads and magnetic sensors, the OCMS approach achieves an output voltage up to 8.1 times higher. Notably, a large oscillation output of 952 mVpp is obtained with sensing current as low as 0.4–0.6 mA flowing through the MTJ. The measured output response shows strong agreement with the TopSPICE simulations, which further predict output voltages exceeding 10 Vpp at a sensing current of 0.82 mA and an operation frequency of 10 MHz. These results demonstrate that the OCMS method enables high-output, low-power, and high-frequency magnetic sensing, offering a promising solution for the next-generation spintronic sensor technologies.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"62 1","pages":"1-7"},"PeriodicalIF":1.9,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145847809","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 : 2025-11-27DOI: 10.1109/TMAG.2025.3638155
Nicoleta Banu;Massimo Pasquale;Fausto Fiorillo
We show that the time-domain formulation of the dynamic losses in soft magnetic materials provided by the statistical theory of losses (STLs) leads to an accurate analytical prediction of energy loss and hysteresis loops in magnetic sheets and soft ferrites under sinusoidal and non-sinusoidal induction. In its generalized form, this theory applies to both conducting and nonconducting materials by separately treating the dissipation phenomena engendered by eddy currents and spin damping. The equations for the classical and excess loss components and the predicted hysteresis loop dependence on the flux waveform are based on the definition and calculation of the instantaneous values of the classical and excess fields, where the material conductivity and the Landau–Lifshitz constant are the intrinsic parameters involved in damping. Energy loss measurements have been performed at different peak polarization values on Fe-Si [grain-oriented and nonoriented (NO)] and Fe-Co (Vacoflux) sheets up to 400 Hz, and on Mn-Zn ferrites (N87) up to 500 kHz. The effect of distortion introduced by either a third or fifth harmonic component, 0°–180° phase-shifted with respect to the fundamental component, is predicted, with and without minor loops, in the soft magnetic sheets. Instead, the Mn-Zn samples are tested under rectangular symmetric/asymmetric voltage, emulating the working regime of dc–dc buck converters. Whatever the case, the predictive method relies on the STL-based time-domain retrieval of the excess and classical viscous fields. This objective is achieved in ferrites through the theoretical prediction of the energy loss due to the spin-damping mechanism, while the skin effect in metallic sheets poses an effective upper-frequency limitation to the analytical approach.
{"title":"Predicting Energy Loss and Hysteresis Loop Under Non-Sinusoidal Induction in Soft Magnetic Sheets and Ferrites","authors":"Nicoleta Banu;Massimo Pasquale;Fausto Fiorillo","doi":"10.1109/TMAG.2025.3638155","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3638155","url":null,"abstract":"We show that the time-domain formulation of the dynamic losses in soft magnetic materials provided by the statistical theory of losses (STLs) leads to an accurate analytical prediction of energy loss and hysteresis loops in magnetic sheets and soft ferrites under sinusoidal and non-sinusoidal induction. In its generalized form, this theory applies to both conducting and nonconducting materials by separately treating the dissipation phenomena engendered by eddy currents and spin damping. The equations for the classical and excess loss components and the predicted hysteresis loop dependence on the flux waveform are based on the definition and calculation of the instantaneous values of the classical and excess fields, where the material conductivity and the Landau–Lifshitz constant are the intrinsic parameters involved in damping. Energy loss measurements have been performed at different peak polarization values on Fe-Si [grain-oriented and nonoriented (NO)] and Fe-Co (Vacoflux) sheets up to 400 Hz, and on Mn-Zn ferrites (N87) up to 500 kHz. The effect of distortion introduced by either a third or fifth harmonic component, 0°–180° phase-shifted with respect to the fundamental component, is predicted, with and without minor loops, in the soft magnetic sheets. Instead, the Mn-Zn samples are tested under rectangular symmetric/asymmetric voltage, emulating the working regime of dc–dc buck converters. Whatever the case, the predictive method relies on the STL-based time-domain retrieval of the excess and classical viscous fields. This objective is achieved in ferrites through the theoretical prediction of the energy loss due to the spin-damping mechanism, while the skin effect in metallic sheets poses an effective upper-frequency limitation to the analytical approach.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"62 2","pages":"1-13"},"PeriodicalIF":1.9,"publicationDate":"2025-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11270955","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146082300","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 : 2025-11-26DOI: 10.1109/TMAG.2025.3634893
{"title":"IEEE Magnetics Society Information","authors":"","doi":"10.1109/TMAG.2025.3634893","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3634893","url":null,"abstract":"","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"61 12","pages":"C2-C2"},"PeriodicalIF":1.9,"publicationDate":"2025-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11269913","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145600710","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}
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