Pub Date : 2025-10-20DOI: 10.1109/TMAG.2025.3623500
Edgar Berrospe-Juarez;Frédéric Sirois
In this article, the boundary element method (BEM) is used to build 2-D magnetic-harmonic models for multi-conductor systems made of thin conductors. The presented BEM models are much more computationally efficient than the equivalent finite element method (FEM) models. The proposed models allow the computation of the field quantities and the circuit parameters of the multiconductor system. Two approaches are presented: 1) the shell approach, for cases where the current density varies across the thickness of the conductor, and 2) the strip approach, for cases where the current density is uniform across the thickness of the conductor. It is demonstrated that the strip approach leads to a significant simplification of the calculations. Voltages and currents are included directly in the system variables and outputs, respectively, avoiding the need for additional post-processing steps. The efficiency of the proposed models is important in cases including a large number of conductors, especially if frequency sweeps are required.
{"title":"Boundary Element Method Analysis of Multi-Conductor Systems Made of Thin Conductors in 2-D","authors":"Edgar Berrospe-Juarez;Frédéric Sirois","doi":"10.1109/TMAG.2025.3623500","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3623500","url":null,"abstract":"In this article, the boundary element method (BEM) is used to build 2-D magnetic-harmonic models for multi-conductor systems made of thin conductors. The presented BEM models are much more computationally efficient than the equivalent finite element method (FEM) models. The proposed models allow the computation of the field quantities and the circuit parameters of the multiconductor system. Two approaches are presented: 1) the shell approach, for cases where the current density varies across the thickness of the conductor, and 2) the strip approach, for cases where the current density is uniform across the thickness of the conductor. It is demonstrated that the strip approach leads to a significant simplification of the calculations. Voltages and currents are included directly in the system variables and outputs, respectively, avoiding the need for additional post-processing steps. The efficiency of the proposed models is important in cases including a large number of conductors, especially if frequency sweeps are required.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"61 12","pages":"1-12"},"PeriodicalIF":1.9,"publicationDate":"2025-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145600667","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 : 2025-10-15DOI: 10.1109/TMAG.2025.3622109
Dan Liu;Zhihao Wang;Changfeng Li;Xiao-Ping Ma;Kaiyou Luo;Je-Ho Shim;Hyeong-Ryoel Park;Hong-Guang Piao
Through micromagnetic simulations, this study demonstrates that when a spin wave propagates in an artificial magnonic domain wall (DW) waveguide, it can induce a spin wave in an adjacent magnonic waveguide via coherent coupling. By leveraging the interference between these two spin waves, magnonic logic devices—specifically, OR and XOR gates—are successfully realized. The logical states of “1” and “0” are achieved via coherent constructive and destructive interference, respectively, by controlling the phase and amplitude of the input wave sources. Furthermore, the relationship between the output amplitude and the phase difference of the input sources is thoroughly investigated, revealing that the logic functionality can be modulated by adjusting the phase difference. In contrast to traditional current-driven logic, this research offers a pathway to design low-power and highly integrated magnonics logic devices without requiring the complex physical modifications inherent in conventional circuits.
{"title":"Reconfigurable Magnonic Logic via Coherent Spin-Wave Interference in Artificial Domain-Wall Waveguides","authors":"Dan Liu;Zhihao Wang;Changfeng Li;Xiao-Ping Ma;Kaiyou Luo;Je-Ho Shim;Hyeong-Ryoel Park;Hong-Guang Piao","doi":"10.1109/TMAG.2025.3622109","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3622109","url":null,"abstract":"Through micromagnetic simulations, this study demonstrates that when a spin wave propagates in an artificial magnonic domain wall (DW) waveguide, it can induce a spin wave in an adjacent magnonic waveguide via coherent coupling. By leveraging the interference between these two spin waves, magnonic logic devices—specifically, OR and XOR gates—are successfully realized. The logical states of “1” and “0” are achieved via coherent constructive and destructive interference, respectively, by controlling the phase and amplitude of the input wave sources. Furthermore, the relationship between the output amplitude and the phase difference of the input sources is thoroughly investigated, revealing that the logic functionality can be modulated by adjusting the phase difference. In contrast to traditional current-driven logic, this research offers a pathway to design low-power and highly integrated magnonics logic devices without requiring the complex physical modifications inherent in conventional circuits.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"61 12","pages":"1-5"},"PeriodicalIF":1.9,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145600708","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 : 2025-10-14DOI: 10.1109/TMAG.2025.3621242
Nguyen Thi Lan;Trinh Duc Minh;Ngo Ngoc My Duyen;Tran Duong Tan Quyen
This study aims to develop a robust and computationally efficient forward model for surface defect characterization in magnetic flux leakage (MFL) testing. The proposed approach extends the magnetic dipole model (MDM) into a numerical MDM (NMDM), enabling the simulation of MFL signals for complex defect geometries. A comprehensive evaluation of multiple defect cases demonstrates the model’s effectiveness. First, the NMDM achieves superior accuracy over analytical MDMs when applied to ellipsoidal defect, with the predicted radial component closely matching finite element method (FEM) simulations, yielding a root mean square error (RMSE) of 3.84%. Second, for complex defects, the method maintains high precision, with RMSE values below 6% relative to FEM results. Third, for corrosion-like defects exhibiting gradual depth variations, the model retains high accuracy, achieving an RMSE of 3.94% compared to experimental data. However, for artificial defects with abrupt depth changes, the prediction error increases, reaching a maximum RMSE of 9.01%. Despite this, the method remains computationally efficient, achieving a runtime of under 1 s for predicting MFL signals at 100 field points. These results confirm that NMDM is a robust and practical approach for corrosion defect characterization, particularly when maintaining a sensor lift-off distance below 2 mm to ensure accurate defect reconstruction.
{"title":"A Fast Forward Model for Surface Defect Characterization in Magnetic Flux Leakage Testing","authors":"Nguyen Thi Lan;Trinh Duc Minh;Ngo Ngoc My Duyen;Tran Duong Tan Quyen","doi":"10.1109/TMAG.2025.3621242","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3621242","url":null,"abstract":"This study aims to develop a robust and computationally efficient forward model for surface defect characterization in magnetic flux leakage (MFL) testing. The proposed approach extends the magnetic dipole model (MDM) into a numerical MDM (NMDM), enabling the simulation of MFL signals for complex defect geometries. A comprehensive evaluation of multiple defect cases demonstrates the model’s effectiveness. First, the NMDM achieves superior accuracy over analytical MDMs when applied to ellipsoidal defect, with the predicted radial component closely matching finite element method (FEM) simulations, yielding a root mean square error (RMSE) of 3.84%. Second, for complex defects, the method maintains high precision, with RMSE values below 6% relative to FEM results. Third, for corrosion-like defects exhibiting gradual depth variations, the model retains high accuracy, achieving an RMSE of 3.94% compared to experimental data. However, for artificial defects with abrupt depth changes, the prediction error increases, reaching a maximum RMSE of 9.01%. Despite this, the method remains computationally efficient, achieving a runtime of under 1 s for predicting MFL signals at 100 field points. These results confirm that NMDM is a robust and practical approach for corrosion defect characterization, particularly when maintaining a sensor lift-off distance below 2 mm to ensure accurate defect reconstruction.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"61 12","pages":"1-9"},"PeriodicalIF":1.9,"publicationDate":"2025-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145600718","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 : 2025-10-13DOI: 10.1109/TMAG.2025.3620561
Diego D. A. C. Reif;Allan M. Döring;Felipe M. Andre;Claudio M. Poffo;Guilherme F. Peixer;Jaime A. Lozano;Jader R. Barbosa;Cristiano S. Teixeira
La(Fe,Si,Mn)13Hz are among the most promising magnetocaloric materials (MCMs) used in room-temperature magnetic refrigeration. They exhibit an intense magnetocaloric effect (MCE), a low content of rare-earth elements, and a tunable Curietemperature ($T_{mathrm {C}}$ ), the temperature at which the MCE reaches its apex. MCMs are assembled in a porous-layered component called active magnetic regenerator (AMR), where the materials are arranged to achieve a gradient of $T_{mathrm {C}}$ values. Since the material constantly changes its magnetic state to trigger the giant MCE, it is important to analyze how its properties behave in both ferroand paramagnetic states. Besides that, although commercially available La(Fe,Si,Mn)13Hz compounds have been used in several studies in recent years, they cannot achieve the expected performance based on lab-made materials. This work investigates how the thermostructural properties of several batches of commercially available La(Fe,Si,Mn)13Hz microspheres, with $T_{mathrm {C}}$ s ranging from 282 to 307 K, vary according to the magnetic state of these materials at its application temperature, the room temperature. X-ray diffraction (XRD) analysis revealed that the magnetic state has a significant influence on the microstructural properties of the MCM. The crystallographic density of the magnetocaloric phase of the materials that were in the ferromagnetic state was about 1% higher than those in the paramagnetic state. Furthermore, the crystallographic results showed that the magnetic state of the magnetocaloric phase also affects the structure of secondary phases present in the material, such as the α-Fe, which suffers a 1% density reduction during the magnetic transition of the magnetocaloric phase. Similarly, photoacoustic absorption spectroscopy (PAS) results unveiled that the samples in the ferromagnetic state have higher values of thermal diffusivity, reaching up to 7.9 mm2/s, while materials in the paramagnetic state range from 4.5 to 5.5 mm2/s. Also, the PAS analysis also highlighted a key difference between commercially available materials and lab-scale compounds, the latter of which have lower values of thermal diffusivity (up to 1.5 mm2/s) because of the lack of a conductive secondary phase. The results presented in this article highlight the importance of considering the differences between the properties of commercially available materials and laboratory-made ones and also the fluctuation of thermal and structural properties depending on the material’s magnetic state, which are key factors when designing magnetic refrigeration prototypes and simulating their performance.
{"title":"Influence of the Magnetic State in the Thermo-Structural Properties of Commercially Available La(Fe,Si,Mn)13Hz Microparticles Applied in Magnetic Refrigeration Prototypes","authors":"Diego D. A. C. Reif;Allan M. Döring;Felipe M. Andre;Claudio M. Poffo;Guilherme F. Peixer;Jaime A. Lozano;Jader R. Barbosa;Cristiano S. Teixeira","doi":"10.1109/TMAG.2025.3620561","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3620561","url":null,"abstract":"La(Fe,Si,Mn)13Hz are among the most promising magnetocaloric materials (MCMs) used in room-temperature magnetic refrigeration. They exhibit an intense magnetocaloric effect (MCE), a low content of rare-earth elements, and a tunable Curietemperature (<inline-formula> <tex-math>$T_{mathrm {C}}$ </tex-math></inline-formula>), the temperature at which the MCE reaches its apex. MCMs are assembled in a porous-layered component called active magnetic regenerator (AMR), where the materials are arranged to achieve a gradient of <inline-formula> <tex-math>$T_{mathrm {C}}$ </tex-math></inline-formula> values. Since the material constantly changes its magnetic state to trigger the giant MCE, it is important to analyze how its properties behave in both ferroand paramagnetic states. Besides that, although commercially available La(Fe,Si,Mn)13Hz compounds have been used in several studies in recent years, they cannot achieve the expected performance based on lab-made materials. This work investigates how the thermostructural properties of several batches of commercially available La(Fe,Si,Mn)13Hz microspheres, with <inline-formula> <tex-math>$T_{mathrm {C}}$ </tex-math></inline-formula>s ranging from 282 to 307 K, vary according to the magnetic state of these materials at its application temperature, the room temperature. X-ray diffraction (XRD) analysis revealed that the magnetic state has a significant influence on the microstructural properties of the MCM. The crystallographic density of the magnetocaloric phase of the materials that were in the ferromagnetic state was about 1% higher than those in the paramagnetic state. Furthermore, the crystallographic results showed that the magnetic state of the magnetocaloric phase also affects the structure of secondary phases present in the material, such as the α-Fe, which suffers a 1% density reduction during the magnetic transition of the magnetocaloric phase. Similarly, photoacoustic absorption spectroscopy (PAS) results unveiled that the samples in the ferromagnetic state have higher values of thermal diffusivity, reaching up to 7.9 mm2/s, while materials in the paramagnetic state range from 4.5 to 5.5 mm2/s. Also, the PAS analysis also highlighted a key difference between commercially available materials and lab-scale compounds, the latter of which have lower values of thermal diffusivity (up to 1.5 mm2/s) because of the lack of a conductive secondary phase. The results presented in this article highlight the importance of considering the differences between the properties of commercially available materials and laboratory-made ones and also the fluctuation of thermal and structural properties depending on the material’s magnetic state, which are key factors when designing magnetic refrigeration prototypes and simulating their performance.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"61 12","pages":"1-8"},"PeriodicalIF":1.9,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145600712","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 : 2025-10-09DOI: 10.1109/TMAG.2025.3619562
Róbert Tarasenko;Ali Darwich;Erik Čižmár;Martin Orendáč;Alžbeta Orendáčová
$mathrm{Cu}(t n) mathrm{Cl}_2left(t n=mathrm{C}_3 mathrm{H}_{10} mathrm{~N}_2right)$ represents a quasi-2D quantum magnet which preserves 2-D features down to mK region despite the setting of magnetic long-range order at 0.55 K. The existence of large quantum fluctuations can be associated with the incommensurate modulated crystal structure. Previous studies of the magnetic phase diagram revealed an additional phase in the vicinity of a critical region. Since the phase appears in the fields perpendicular to the modulation vector, its dependence on the field orientation may have its origin in the spatial and spin anisotropies. The latter can be estimated from the electron paramagnetic resonance (EPR) spectra. The present work is devoted to the X-band single crystal studies of the angular and temperature dependence of EPR spectra. Angular dependence of linewidth within the $a b$ and $a c$ planes shows $cos ^2 theta$ dependence associated with the contribution of spin anisotropies. The analysis of the temperature dependence of linewidth along the $a$ - and $b$ -axis enabled the quantitative estimation of spin anisotropies. In the field parallel to $a$ -axis, which is perpendicular to the modulation vector, the linewidth is determined by the combined contribution of exchange-narrowed dipolar coupling, antisymmetric Dzyaloshinskii-Moriya (DM) interaction, and symmetric spin anisotropies of dipolar origin $K^{text {dip }}$ and exchange anisotropy $bar{K}^{text {EA }}$ . The absence of the additional phase in the magnetic phase diagram along the $b$ -axis, as well as symmetry requirements, suggests that the DM contribution along the $b$ -axis could be neglected, and the linewidth is dominated by the contribution of symmetric spin anisotropies.
{"title":"EPR Study of Spin Anisotropies in the S = 1/2 Spatially Anisotropic Triangular Quantum Magnet Cu(tn)Cl2","authors":"Róbert Tarasenko;Ali Darwich;Erik Čižmár;Martin Orendáč;Alžbeta Orendáčová","doi":"10.1109/TMAG.2025.3619562","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3619562","url":null,"abstract":"<inline-formula> <tex-math>$mathrm{Cu}(t n) mathrm{Cl}_2left(t n=mathrm{C}_3 mathrm{H}_{10} mathrm{~N}_2right)$ </tex-math></inline-formula> represents a quasi-2D quantum magnet which preserves 2-D features down to mK region despite the setting of magnetic long-range order at 0.55 K. The existence of large quantum fluctuations can be associated with the incommensurate modulated crystal structure. Previous studies of the magnetic phase diagram revealed an additional phase in the vicinity of a critical region. Since the phase appears in the fields perpendicular to the modulation vector, its dependence on the field orientation may have its origin in the spatial and spin anisotropies. The latter can be estimated from the electron paramagnetic resonance (EPR) spectra. The present work is devoted to the X-band single crystal studies of the angular and temperature dependence of EPR spectra. Angular dependence of linewidth within the <inline-formula> <tex-math>$a b$ </tex-math></inline-formula> and <inline-formula> <tex-math>$a c$ </tex-math></inline-formula> planes shows <inline-formula> <tex-math>$cos ^2 theta$ </tex-math></inline-formula> dependence associated with the contribution of spin anisotropies. The analysis of the temperature dependence of linewidth along the <inline-formula> <tex-math>$a$ </tex-math></inline-formula>- and <inline-formula> <tex-math>$b$ </tex-math></inline-formula>-axis enabled the quantitative estimation of spin anisotropies. In the field parallel to <inline-formula> <tex-math>$a$ </tex-math></inline-formula>-axis, which is perpendicular to the modulation vector, the linewidth is determined by the combined contribution of exchange-narrowed dipolar coupling, antisymmetric Dzyaloshinskii-Moriya (DM) interaction, and symmetric spin anisotropies of dipolar origin <inline-formula> <tex-math>$K^{text {dip }}$ </tex-math></inline-formula> and exchange anisotropy <inline-formula> <tex-math>$bar{K}^{text {EA }}$ </tex-math></inline-formula>. The absence of the additional phase in the magnetic phase diagram along the <inline-formula> <tex-math>$b$ </tex-math></inline-formula>-axis, as well as symmetry requirements, suggests that the DM contribution along the <inline-formula> <tex-math>$b$ </tex-math></inline-formula>-axis could be neglected, and the linewidth is dominated by the contribution of symmetric spin anisotropies.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"61 12","pages":"1-4"},"PeriodicalIF":1.9,"publicationDate":"2025-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145600680","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}
In this article, an enhanced physics-informed neural network (PINN) framework is proposed for accurate time-domain electromagnetic field computation in power transformers. To address the numerical stiffness and convergence challenges arising from steep field gradients between ferromagnetic cores, dielectric materials, and multi-layer windings, the high-frequency representation capability of the SIREN network architecture is leveraged. A novel adaptive collocation point sampling strategy is developed to dynamically refine spatial–temporal sampling resolution in high-gradient regions, effectively balancing numerical accuracy with computational efficiency. The proposed framework rigorously embeds Maxwell’s equations and composite boundary conditions into the loss formulation, establishing a surrogate model for 2-D electromagnetic field computation. Numerical results demonstrate a twoorder- of-magnitude reduction in prediction error compared to vanilla PINNs with a random sampling strategy. This breakthrough enables efficient simulation of time-domain multiphysics fields in complex electromagnetic devices featuring intricate geometries and multi-material interfaces.
{"title":"SAS-PINN: An Enhanced Physics-Informed Neural Network for 2-D Time-Domain Electromagnetic Field Computation of Power Transformer","authors":"Ruimin Zhu;Xutao Cong;Shiyu Pu;Ning Lin;Venkata Dinavahi","doi":"10.1109/TMAG.2025.3618865","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3618865","url":null,"abstract":"In this article, an enhanced physics-informed neural network (PINN) framework is proposed for accurate time-domain electromagnetic field computation in power transformers. To address the numerical stiffness and convergence challenges arising from steep field gradients between ferromagnetic cores, dielectric materials, and multi-layer windings, the high-frequency representation capability of the SIREN network architecture is leveraged. A novel adaptive collocation point sampling strategy is developed to dynamically refine spatial–temporal sampling resolution in high-gradient regions, effectively balancing numerical accuracy with computational efficiency. The proposed framework rigorously embeds Maxwell’s equations and composite boundary conditions into the loss formulation, establishing a surrogate model for 2-D electromagnetic field computation. Numerical results demonstrate a twoorder- of-magnitude reduction in prediction error compared to vanilla PINNs with a random sampling strategy. This breakthrough enables efficient simulation of time-domain multiphysics fields in complex electromagnetic devices featuring intricate geometries and multi-material interfaces.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"61 12","pages":"1-8"},"PeriodicalIF":1.9,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145600685","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 : 2025-10-06DOI: 10.1109/TMAG.2025.3618008
I. Khmara;M. Kubovcikova;M. Molcan;V. Girman;M. Fabian;K. Hreus;V. Zavisova;M. Koneracka
The single- and multicore iron oxide nanoparticles (IONPs) were synthesized, and their structural and magnetic properties were evaluated to assess their applicability in magnetic hyperthermia. Whereas the single-core IONPs obtained by the co-precipitation method consisted of roughly spherical particles with an average magnetic core diameter of ~10 nm, the multicore IONPs, prepared by applying the standard polyol protocol, exhibited a characteristic morphology: they looked like they were composed of smaller grains of ~9 nm, assembled in a flower-shaped structure with an overall diameter of ~30 nm. The experimental evaluation of the specific absorption rate (SAR) of both single-core IONPs and multicore IONPs was conducted by calorimetric measurements. The SAR values of both samples increased with the applied magnetic fields H up to ~7.9 kA·m-1, with multicore IONPs showing significantly higher SAR than single-core IONPs. These results highlight the potential of multicore IONPs as efficient nanoheaters for hyperthermia-based cancer treatment.
{"title":"Comparative Characterization of Structural, Magnetic Properties, and Heating Efficiency of Single- and Multicore Iron Oxide Nanoparticles","authors":"I. Khmara;M. Kubovcikova;M. Molcan;V. Girman;M. Fabian;K. Hreus;V. Zavisova;M. Koneracka","doi":"10.1109/TMAG.2025.3618008","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3618008","url":null,"abstract":"The single- and multicore iron oxide nanoparticles (IONPs) were synthesized, and their structural and magnetic properties were evaluated to assess their applicability in magnetic hyperthermia. Whereas the single-core IONPs obtained by the co-precipitation method consisted of roughly spherical particles with an average magnetic core diameter of ~10 nm, the multicore IONPs, prepared by applying the standard polyol protocol, exhibited a characteristic morphology: they looked like they were composed of smaller grains of ~9 nm, assembled in a flower-shaped structure with an overall diameter of ~30 nm. The experimental evaluation of the specific absorption rate (SAR) of both single-core IONPs and multicore IONPs was conducted by calorimetric measurements. The SAR values of both samples increased with the applied magnetic fields H up to ~7.9 kA·m-1, with multicore IONPs showing significantly higher SAR than single-core IONPs. These results highlight the potential of multicore IONPs as efficient nanoheaters for hyperthermia-based cancer treatment.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"61 11","pages":"1-5"},"PeriodicalIF":1.9,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145455933","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 : 2025-10-06DOI: 10.1109/TMAG.2025.3618122
V. Balayeva;D. Romanenko;S. Nikitov;M. Morozova
The study of the features of spin-wave (SW) propagation in a magnonic crystal (MC) based on a nanoscale ferromagnetic film (FF) made of yttrium iron garnet (YIG) with a periodic system of grooves on the surface was carried out using micromagnetic simulation software MuMax3. It is shown that in such a structure, the signal intensity in the grooves exceeds that in the ridges. It was found that the structure periodicity leads to fragmentation of the SW intensity over the one period length. Additional modes are formed on the dispersion characteristics of MC near each fundamental width mode. Changing the ratio of ridge and groove widths leads to a shift in the cutoff frequencies of the fundamental and additional modes.
{"title":"Influence of Geometrical Parameters of Nanoscale Magnonic Crystal on Spin-Wave Propagation","authors":"V. Balayeva;D. Romanenko;S. Nikitov;M. Morozova","doi":"10.1109/TMAG.2025.3618122","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3618122","url":null,"abstract":"The study of the features of spin-wave (SW) propagation in a magnonic crystal (MC) based on a nanoscale ferromagnetic film (FF) made of yttrium iron garnet (YIG) with a periodic system of grooves on the surface was carried out using micromagnetic simulation software MuMax3. It is shown that in such a structure, the signal intensity in the grooves exceeds that in the ridges. It was found that the structure periodicity leads to fragmentation of the SW intensity over the one period length. Additional modes are formed on the dispersion characteristics of MC near each fundamental width mode. Changing the ratio of ridge and groove widths leads to a shift in the cutoff frequencies of the fundamental and additional modes.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"61 12","pages":"1-6"},"PeriodicalIF":1.9,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145600721","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 : 2025-10-01DOI: 10.1109/TMAG.2025.3616152
Jinji Sun;Airu Ji;Gen Xing;Haoxi Sun
Precision attitude control in aerospace systems requires drag-cup permanent magnet brushless dc motors with extremely low torque ripple. Conventional permanent magnet sinusoidal shaping (PMSS) can reduce air-gap field total harmonic distortion (THD) but typically relies on a single eccentricity configuration, which can approach process or magnetization limits and produce suboptimal flux waveforms. This article introduces a novel combined eccentricity design approach that integrates permanent magnets (PMs) and inner rotor sinusoidal shaping (PMIRSS), guided by the equivalent surface current method and finite element analysis (FEA). Various eccentricity combinations are evaluated through static simulations and validated experimentally. The proposed design reduces air-gap THD to 2.26%, compared to 29.62% for the non-eccentric baseline, a reduction of 92.4% while maintaining a competitive maximum flux density ($B_{text {max }}$ ). These results demonstrate a strong synergistic effect between rotor and PM eccentricity. Based on the results, this article proposes recommendations for normalized eccentricity and an appropriate $B_{text {max }}$ interval to improve cross-scale compatibility. The results show that simultaneously optimizing the eccentricity of the rotor and PMs can produce uniform air-gap flux, suppress high-order harmonics, and avoid local saturation, resulting in smoother torque and minimized ripple. The combined eccentric motor is ideal for high-precision aerospace applications such as control torque gyroscopes, magnetically levitated flywheels, and high-power precision drives.
{"title":"Static Analysis and Eccentric Design Combining Permanent Magnets With Inner Rotor on Drag-Cup Motor","authors":"Jinji Sun;Airu Ji;Gen Xing;Haoxi Sun","doi":"10.1109/TMAG.2025.3616152","DOIUrl":"https://doi.org/10.1109/TMAG.2025.3616152","url":null,"abstract":"Precision attitude control in aerospace systems requires drag-cup permanent magnet brushless dc motors with extremely low torque ripple. Conventional permanent magnet sinusoidal shaping (PMSS) can reduce air-gap field total harmonic distortion (THD) but typically relies on a single eccentricity configuration, which can approach process or magnetization limits and produce suboptimal flux waveforms. This article introduces a novel combined eccentricity design approach that integrates permanent magnets (PMs) and inner rotor sinusoidal shaping (PMIRSS), guided by the equivalent surface current method and finite element analysis (FEA). Various eccentricity combinations are evaluated through static simulations and validated experimentally. The proposed design reduces air-gap THD to 2.26%, compared to 29.62% for the non-eccentric baseline, a reduction of 92.4% while maintaining a competitive maximum flux density (<inline-formula> <tex-math>$B_{text {max }}$ </tex-math></inline-formula>). These results demonstrate a strong synergistic effect between rotor and PM eccentricity. Based on the results, this article proposes recommendations for normalized eccentricity and an appropriate <inline-formula> <tex-math>$B_{text {max }}$ </tex-math></inline-formula> interval to improve cross-scale compatibility. The results show that simultaneously optimizing the eccentricity of the rotor and PMs can produce uniform air-gap flux, suppress high-order harmonics, and avoid local saturation, resulting in smoother torque and minimized ripple. The combined eccentric motor is ideal for high-precision aerospace applications such as control torque gyroscopes, magnetically levitated flywheels, and high-power precision drives.","PeriodicalId":13405,"journal":{"name":"IEEE Transactions on Magnetics","volume":"61 11","pages":"1-9"},"PeriodicalIF":1.9,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145455754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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