Pub Date : 2025-12-29DOI: 10.1109/TMAG.2025.3645176
{"title":"IEEE Magnetics Society Information","authors":"","doi":"10.1109/TMAG.2025.3645176","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3645176","url":null,"abstract":"","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"62 1","pages":"C2-C2"},"PeriodicalIF":1.9,"publicationDate":"2025-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11318117","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145847831","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 : 2025-12-05DOI: 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 : 2025-11-26DOI: 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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