Pub Date : 2026-03-15Epub Date: 2026-01-31DOI: 10.1016/j.jmmm.2026.173897
Michal Ulvr , Franziska Weickert , Korbinian Pfnuer , Joachim Lüdke , Katja Hoffmann , Stuart Harmon , Daniel Brunt , Adam Wilson , Massimo Pasquale , Carlo Appino , Chris Gerada , Ram Ramanathan Mathavan jeyabalan , Gaurang Vakil
Epstein frame and single sheet tester are two methods used for measurement of power losses of the electrical steel sheets or strips. Both methods and the setups are described in the IEC standards. Each national metrology institute or other metrological laboratory has different setups for power losses measurement and the validation of its accuracy and parameters can only be done by comparisons. So far, every performed comparison was carried out only at 50 Hz or 60 Hz. Within the EMPIR project “HEFMAG”, improved metrological infrastructure for the determination of power losses using Epstein frame at induction values close to saturation and at frequency ranges between 2 kHz and to 10 kHz was built. To validate the improved setups, a round robin comparison of power loss measurements was conducted by five laboratories. The results of the round robin comparison are discussed including measurement uncertainties.
{"title":"Round robin comparison of power losses performed by epstein frame and sst above 50 hz at room temperature","authors":"Michal Ulvr , Franziska Weickert , Korbinian Pfnuer , Joachim Lüdke , Katja Hoffmann , Stuart Harmon , Daniel Brunt , Adam Wilson , Massimo Pasquale , Carlo Appino , Chris Gerada , Ram Ramanathan Mathavan jeyabalan , Gaurang Vakil","doi":"10.1016/j.jmmm.2026.173897","DOIUrl":"10.1016/j.jmmm.2026.173897","url":null,"abstract":"<div><div>Epstein frame and single sheet tester are two methods used for measurement of power losses of the electrical steel sheets or strips. Both methods and the setups are described in the IEC standards. Each national metrology institute or other metrological laboratory has different setups for power losses measurement and the validation of its accuracy and parameters can only be done by comparisons. So far, every performed comparison was carried out only at 50 Hz or 60 Hz. Within the EMPIR project “HEFMAG”, improved metrological infrastructure for the determination of power losses using Epstein frame at induction values close to saturation and at frequency ranges between 2 kHz and to 10 kHz was built. To validate the improved setups, a round robin comparison of power loss measurements was conducted by five laboratories. The results of the round robin comparison are discussed including measurement uncertainties.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"642 ","pages":"Article 173897"},"PeriodicalIF":3.0,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146185802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We present a perspective on recent progress in machine-learning (ML) force-field approaches for large-scale Landau–Lifshitz–Gilbert (LLG) simulations of metallic spin systems. Building on a generalization of the Behler–Parrinello (BP) architecture originally developed for quantum molecular dynamics, we develop scalable and transferable ML models that faithfully capture the complex, environment-dependent electron-mediated exchange fields characteristic of itinerant magnets. A central ingredient of this framework is the implementation of symmetry-aware magnetic descriptors based on group-theoretical bispectrum formalisms. Leveraging these ML force fields, LLG simulations faithfully reproduce hallmark non-collinear magnetic orders—such as the 120° and tetrahedral states—on the triangular lattice, and successfully capture the complex spin textures emerging in the mixed-phase states of a square-lattice double-exchange model under thermal quench. We further discuss a generalized potential theory that extends the BP formalism to incorporate both conservative and nonconservative electronic torques, thereby enabling ML models to learn nonequilibrium exchange fields from computationally demanding microscopic approaches such as nonequilibrium Green’s-function techniques. This extension yields quantitatively accurate predictions of voltage-driven domain-wall motion and establishes a foundation for quantum-accurate, multiscale modeling of nonequilibrium spin dynamics and spintronic functionalities.
{"title":"Machine-learning modeling of magnetization dynamics in quasi-equilibrium and driven metallic spin systems","authors":"Gia-Wei Chern, Yunhao Fan, Sheng Zhang, Puhan Zhang","doi":"10.1016/j.jmmm.2026.173898","DOIUrl":"10.1016/j.jmmm.2026.173898","url":null,"abstract":"<div><div>We present a perspective on recent progress in machine-learning (ML) force-field approaches for large-scale Landau–Lifshitz–Gilbert (LLG) simulations of metallic spin systems. Building on a generalization of the Behler–Parrinello (BP) architecture originally developed for quantum molecular dynamics, we develop scalable and transferable ML models that faithfully capture the complex, environment-dependent electron-mediated exchange fields characteristic of itinerant magnets. A central ingredient of this framework is the implementation of symmetry-aware magnetic descriptors based on group-theoretical bispectrum formalisms. Leveraging these ML force fields, LLG simulations faithfully reproduce hallmark non-collinear magnetic orders—such as the 120° and tetrahedral states—on the triangular lattice, and successfully capture the complex spin textures emerging in the mixed-phase states of a square-lattice double-exchange model under thermal quench. We further discuss a generalized potential theory that extends the BP formalism to incorporate both conservative and nonconservative electronic torques, thereby enabling ML models to learn nonequilibrium exchange fields from computationally demanding microscopic approaches such as nonequilibrium Green’s-function techniques. This extension yields quantitatively accurate predictions of voltage-driven domain-wall motion and establishes a foundation for quantum-accurate, multiscale modeling of nonequilibrium spin dynamics and spintronic functionalities.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"642 ","pages":"Article 173898"},"PeriodicalIF":3.0,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146185909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-15Epub Date: 2026-02-05DOI: 10.1016/j.jmmm.2026.173905
Rishav De , Dipak Mazumdar , Amanulla Karikar , Kalipada Das , I. Das
We report a comprehensive study of the magnetic and magnetocaloric properties of polycrystalline Pr0.3Gd0.3Ca0.4MnO, a rare-earth mixed manganite synthesized via the sol–gel method. Temperature-dependent magnetization data reveal an antiferromagnetic (AFM) transition near K, followed by the emergence of a ferrimagnetic-like state below K, without any apparent charge ordering up to 300 K. Isothermal magnetization and Arrott plot analyses confirm a second-order-like magnetic phase transition. The magnetic entropy change (), derived from isothermal – curves, shows a broad peak around 100 K corresponding to the AFM transition, and a sharp increase below 50 K, reaching a maximum of approximately 5.9 J kg−1 K−1 at K for kOe. A power-law analysis reveals that the exponent in the relation remains nearly constant () over a wide temperature and field range, indicating field- and temperature-independent magnetocaloric behavior. This behavior enabled the successful construction of a universal master curve of without rescaling the temperature axis. The collapse of entropy curves under high magnetic fields further supports the presence of inverse magnetocaloric-like universal scaling, despite the system exhibiting conventional MCE features. These findings highlight the role of rare-earth site disorder in stabilizing complex spin states and enhancing low-temperature magnetocaloric performance.
{"title":"Magnetic and magnetocaloric properties of polycrystalline Pr0.3Gd0.3Ca0.4MnO3 compound","authors":"Rishav De , Dipak Mazumdar , Amanulla Karikar , Kalipada Das , I. Das","doi":"10.1016/j.jmmm.2026.173905","DOIUrl":"10.1016/j.jmmm.2026.173905","url":null,"abstract":"<div><div>We report a comprehensive study of the magnetic and magnetocaloric properties of polycrystalline Pr<sub>0.3</sub>Gd<sub>0.3</sub>Ca<sub>0.4</sub>MnO<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>, a rare-earth mixed manganite synthesized via the sol–gel method. Temperature-dependent magnetization data reveal an antiferromagnetic (AFM) transition near <span><math><mrow><mi>T</mi><mo>≈</mo><mn>100</mn></mrow></math></span> <!--> <!-->K, followed by the emergence of a ferrimagnetic-like state below <span><math><mrow><mi>T</mi><mo>≈</mo><mn>50</mn></mrow></math></span> <!--> <!-->K, without any apparent charge ordering up to 300<!--> <!-->K. Isothermal magnetization and Arrott plot analyses confirm a second-order-like magnetic phase transition. The magnetic entropy change (<span><math><mrow><mo>−</mo><mi>Δ</mi><mi>S</mi></mrow></math></span>), derived from isothermal <span><math><mi>M</mi></math></span>–<span><math><mi>H</mi></math></span> curves, shows a broad peak around 100 K corresponding to the AFM transition, and a sharp increase below 50 K, reaching a maximum of approximately 5.9<!--> <!-->J<!--> <!-->kg<sup>−1</sup> <!-->K<sup>−1</sup> at <span><math><mrow><mi>T</mi><mo>=</mo><mn>7</mn><mo>.</mo><mn>5</mn></mrow></math></span> <!--> <!-->K for <span><math><mrow><mi>Δ</mi><mi>H</mi><mo>=</mo><mn>0</mn><mtext>–</mtext><mn>70</mn></mrow></math></span> kOe. A power-law analysis reveals that the exponent <span><math><mi>n</mi></math></span> in the relation <span><math><mrow><mi>Δ</mi><msub><mrow><mi>S</mi></mrow><mrow><mi>M</mi></mrow></msub><mo>∝</mo><msup><mrow><mi>H</mi></mrow><mrow><mi>n</mi></mrow></msup></mrow></math></span> remains nearly constant (<span><math><mrow><mi>n</mi><mo>≈</mo><mn>1</mn><mo>.</mo><mn>8</mn></mrow></math></span>) over a wide temperature and field range, indicating field- and temperature-independent magnetocaloric behavior. This behavior enabled the successful construction of a universal master curve of <span><math><mrow><mo>−</mo><mi>Δ</mi><mi>S</mi></mrow></math></span> without rescaling the temperature axis. The collapse of entropy curves under high magnetic fields further supports the presence of inverse magnetocaloric-like universal scaling, despite the system exhibiting conventional MCE features. These findings highlight the role of rare-earth site disorder in stabilizing complex spin states and enhancing low-temperature magnetocaloric performance.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"642 ","pages":"Article 173905"},"PeriodicalIF":3.0,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146185898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-15Epub Date: 2026-01-24DOI: 10.1016/j.jmmm.2026.173865
Adler Gamzatov , Petr Igoshev , Nurizhat Abdulkadirova , Anvar Kadirbardeev
The results of measurements of magnetization, magnetostriction and magnetocaloric effect and their correlation analysis near the critical temperature TC of the ferromagnet–paramagnet phase transition of the LaFe11.1Mn0.1Co0.7Si1.1 alloy are presented. In finite magnetic field the character of magnetization M dependence of magnetostriction λ exhibits strong temperature dependence in the vicinity of critical temperature TC: in the vicinity of critical temperature T = TC standard quadratic dependence of λ(M) is insufficient to explain experimental data, instead we find λ = AM2 + BM4, in a qualitative agreement with the self-consistent spin renormalization theory by Moriya and Takahashi, where A and B are temperature dependent coefficients and A vanishes near critical temperature but not exactly at T = TC. Correlation analysis of temperature dependences of magnetocaloric effect ΔSM and longitudinal magnetostriction λ|| showed that in magnetic fields of 18, 40 and 80 kOe near ТС a linear relationship is observed between ΔSM and λ||, ΔSM = - κλ||, with proportionality coefficient κ=9.52⋅103 J/kg K. Within the framework of the Heisenberg model taking into account magnetostriction the value of proportionality coefficient between ΔSM and λ|| is estimated.
{"title":"Relation between magnetic and magnetocaloric properties near the phase transition point in the LaFe11.1Mn0.1Co0.7Si1.1 alloy","authors":"Adler Gamzatov , Petr Igoshev , Nurizhat Abdulkadirova , Anvar Kadirbardeev","doi":"10.1016/j.jmmm.2026.173865","DOIUrl":"10.1016/j.jmmm.2026.173865","url":null,"abstract":"<div><div>The results of measurements of magnetization, magnetostriction and magnetocaloric effect and their correlation analysis near the critical temperature T<sub>C</sub> of the ferromagnet–paramagnet phase transition of the LaFe<sub>11.1</sub>Mn<sub>0.1</sub>Co<sub>0.7</sub>Si<sub>1.1</sub> alloy are presented. In finite magnetic field the character of magnetization M dependence of magnetostriction λ exhibits strong temperature dependence in the vicinity of critical temperature T<sub>C</sub>: in the vicinity of critical temperature T = T<sub>C</sub> standard quadratic dependence of λ(M) is insufficient to explain experimental data, instead we find λ = AM<sup>2</sup> + BM<sup>4</sup>, in a qualitative agreement with the self-consistent spin renormalization theory by Moriya and Takahashi, where A and B are temperature dependent coefficients and A vanishes near critical temperature but not exactly at T = T<sub>C</sub>. Correlation analysis of temperature dependences of magnetocaloric effect ΔS<sub>M</sub> and longitudinal magnetostriction λ<sub>||</sub> showed that in magnetic fields of 18, 40 and 80 kOe near Т<sub>С</sub> a linear relationship is observed between ΔS<sub>M</sub> and λ<sub>||</sub>, ΔS<sub>M</sub> = - κλ<sub>||</sub>, with proportionality coefficient κ=9.52⋅10<sup>3</sup> J/kg K. Within the framework of the Heisenberg model taking into account magnetostriction the value of proportionality coefficient between ΔS<sub>M</sub> and λ<sub>||</sub> is estimated.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"642 ","pages":"Article 173865"},"PeriodicalIF":3.0,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146185930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-15Epub Date: 2026-01-16DOI: 10.1016/j.jmmm.2026.173845
O. Messal, A. Benabou
In this article, an ad hoc method to identify adequate full permeability tensors of grain oriented electrical steels (GOES) is proposed for implementation in finite element method (FEM) simulation. The tensors are obtained from dedicated measurements requiring only unidirectional excitation field. This method relies, on the one hand, on Enokizono's approach which was originally established based on measurements under rotating field and, on the other hand, on Fiorillo's model of magnetization processes in GOES. The derived full permeability tensors have been tested for different angle orientations of applied field to the rolling direction. The identified tensors have been used in a 3D FEM simulation of the Epstein frame and the results have been compared to experimental measurements. The proposed approach demonstrates a potential advantage over a conventional diagonal tensor-based approach, based on the results presented.
{"title":"Ad hoc approach for identifying permeability tensors for numerical simulation of grain-oriented electrical steels","authors":"O. Messal, A. Benabou","doi":"10.1016/j.jmmm.2026.173845","DOIUrl":"10.1016/j.jmmm.2026.173845","url":null,"abstract":"<div><div>In this article, an ad hoc method to identify adequate full permeability tensors of grain oriented electrical steels (GOES) is proposed for implementation in finite element method (FEM) simulation. The tensors are obtained from dedicated measurements requiring only unidirectional excitation field. This method relies, on the one hand, on Enokizono's approach which was originally established based on measurements under rotating field and, on the other hand, on Fiorillo's model of magnetization processes in GOES. The derived full permeability tensors have been tested for different angle orientations of applied field to the rolling direction. The identified tensors have been used in a 3D FEM simulation of the Epstein frame and the results have been compared to experimental measurements. The proposed approach demonstrates a potential advantage over a conventional diagonal tensor-based approach, based on the results presented.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"642 ","pages":"Article 173845"},"PeriodicalIF":3.0,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146185931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-15Epub Date: 2026-01-22DOI: 10.1016/j.jmmm.2026.173847
Alma Partos , Igor Di Marco , Shivalika Sharma
The study of magnetism in transition metals is a cornerstone in understanding complex electronic and magnetic interactions in condensed matter systems. Among transition metal elements, body-centered cubic (bcc) chromium stands out because of its spin-density wave (SDW) ground state, posing a long-standing challenge for density functional theory (DFT). Conventional functionals, such as the generalized-gradient approximation (GGA) and the local-density approximation (LDA), fail to predict this experimentally observed incommensurate SDW as the ground state. In this study, we present a comprehensive DFT analysis of bcc Cr employing GGA and a variety of meta-GGA functionals. We evaluated total energies, structural parameters, and magnetic properties across a wide range of SDW wave vectors. Our results show that all meta-GGA functionals overestimate the local magnetic moments and enhance the nodal magnetic frustration, destabilizing the SDW state relative to the commensurate antiferromagnetic (AF) configuration. Tao–Perdew–Staroverov–Scuseria (TPSS) yields results closest to those of the GGA, thus providing the most adequate description of bcc Cr among the meta-GGA functionals. These results emphasize the need for the further development of non-local or hybrid functionals tailored for complex magnetic systems.
{"title":"A first-principles study of bcc chromium beyond the generalized gradient approximation (GGA)","authors":"Alma Partos , Igor Di Marco , Shivalika Sharma","doi":"10.1016/j.jmmm.2026.173847","DOIUrl":"10.1016/j.jmmm.2026.173847","url":null,"abstract":"<div><div>The study of magnetism in transition metals is a cornerstone in understanding complex electronic and magnetic interactions in condensed matter systems. Among transition metal elements, body-centered cubic (bcc) chromium stands out because of its spin-density wave (SDW) ground state, posing a long-standing challenge for density functional theory (DFT). Conventional functionals, such as the generalized-gradient approximation (GGA) and the local-density approximation (LDA), fail to predict this experimentally observed incommensurate SDW as the ground state. In this study, we present a comprehensive DFT analysis of bcc Cr employing GGA and a variety of meta-GGA functionals. We evaluated total energies, structural parameters, and magnetic properties across a wide range of SDW wave vectors. Our results show that all meta-GGA functionals overestimate the local magnetic moments and enhance the nodal magnetic frustration, destabilizing the SDW state relative to the commensurate antiferromagnetic (AF) configuration. Tao–Perdew–Staroverov–Scuseria (TPSS) yields results closest to those of the GGA, thus providing the most adequate description of bcc Cr among the meta-GGA functionals. These results emphasize the need for the further development of non-local or hybrid functionals tailored for complex magnetic systems.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"642 ","pages":"Article 173847"},"PeriodicalIF":3.0,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146185932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-15Epub Date: 2026-02-09DOI: 10.1016/j.jmmm.2026.173923
J.Z. Sun
Spin-torque switching of nanomagnets in tunnel junction based random access memory requires understanding of finite temperature statistics beyond simple macrospin-limit. The next simplest model beyond macrospin is a two-macrospin coupled system. We extend an earlier two-moment finite temperature study to a two-moment antiferromagnetically coupled model system. In a limited region of spin-current, antiferromagnetic coupling allows for faster spin-torque switching at lower threshold spin-current compared to the same moments coupled ferromagnetically. However, spin-torque switching in antiferromagnetically coupled case is more complex. There is only a narrow window in spin-current for reliable switching. At higher spin-current, a 2nd instability threshold emerges, above which the switching error-rate rises. This is associated with the forced alignment towards spin-polarization direction for both moments under spin-torque, due to precession induced dynamic coupling between the two moments. It results in occupation of higher energy intermediate states under spin-torque, resembling a pumped spin system’s “negative temperature”-like state-population inversion. These moment-near-parallel intermediate states upon spin-torque withdrawal relax back into antiferromagnetic alignment with a finite probability of settling into the “wrong” moment orientations. We discuss this behavior through finite temperature numerical modeling and by comparing numerical results with analytical estimates of linear instability thresholds. This simple model demonstrates the importance of internal degrees of freedom in coupled magnetic moment systems under spin-torque, especially in antiferromagnetic or non-collinear configurations. For fast switching speeds well below 10 ns to reach deep write-error floors, it may require higher exchange strength than demonstrated so far.
{"title":"Spin-transfer switching at ambient temperature in an antiferromagnetically coupled two-macrospin model system","authors":"J.Z. Sun","doi":"10.1016/j.jmmm.2026.173923","DOIUrl":"10.1016/j.jmmm.2026.173923","url":null,"abstract":"<div><div>Spin-torque switching of nanomagnets in tunnel junction based random access memory requires understanding of finite temperature statistics beyond simple macrospin-limit. The next simplest model beyond macrospin is a two-macrospin coupled system. We extend an earlier two-moment finite temperature study to a two-moment antiferromagnetically coupled model system. In a limited region of spin-current, antiferromagnetic coupling allows for faster spin-torque switching at lower threshold spin-current compared to the same moments coupled ferromagnetically. However, spin-torque switching in antiferromagnetically coupled case is more complex. There is only a narrow window in spin-current for reliable switching. At higher spin-current, a 2nd instability threshold emerges, above which the switching error-rate rises. This is associated with the forced alignment towards spin-polarization direction for both moments under spin-torque, due to precession induced dynamic coupling between the two moments. It results in occupation of higher energy intermediate states under spin-torque, resembling a pumped spin system’s “negative temperature”-like state-population inversion. These moment-near-parallel intermediate states upon spin-torque withdrawal relax back into antiferromagnetic alignment with a finite probability of settling into the “wrong” moment orientations. We discuss this behavior through finite temperature numerical modeling and by comparing numerical results with analytical estimates of linear instability thresholds. This simple model demonstrates the importance of internal degrees of freedom in coupled magnetic moment systems under spin-torque, especially in antiferromagnetic or non-collinear configurations. For fast switching speeds well below 10 ns to reach deep write-error floors, it may require higher exchange strength than demonstrated so far.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"642 ","pages":"Article 173923"},"PeriodicalIF":3.0,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146185939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We proposed and theoretically demonstrated a spin-wave (SW) focusing based on a periodic ferromagnetic nanodot array. By exploiting the periodic anisotropic dispersion and the resulting SW caustics, the array concentrates propagating SW power and injects it into an attached nanostripe waveguide. Micromagnetic simulations reveal that the SW caustics generate a pronounced SW focus region in the sub-micrometer scale. The focal position and frequency are tunable via the nanodot geometric shape and external bias magnetic fields. Attaching a narrow nanostripe to the focal region, the concentrated SW is efficiently coupled into the stripe and excites guided SW mode. Furthermore, by transversely shifting the focal point via a bias field, we selectively route SW to different attached nanostripes and even entirely suppress the injection, without modifying the structure. Our results enable sub-micrometer SW focusing, efficient injection, and dynamically reconfigurable multi-port routing within a compact nanodot array platform.
{"title":"Spin wave focusing and reconfigurable routing in a magnetic nanodot array","authors":"Zhang-lin Zhu , Zhi-wu Xie , Qiang Fu, Ying-jie Qin, Lu-lu Zeng, Zhi-xiong Li, Guang-hua Guo, Xi-guang Wang","doi":"10.1016/j.jmmm.2026.173901","DOIUrl":"10.1016/j.jmmm.2026.173901","url":null,"abstract":"<div><div>We proposed and theoretically demonstrated a spin-wave (SW) focusing based on a periodic ferromagnetic nanodot array. By exploiting the periodic anisotropic dispersion and the resulting SW caustics, the array concentrates propagating SW power and injects it into an attached nanostripe waveguide. Micromagnetic simulations reveal that the SW caustics generate a pronounced SW focus region in the sub-micrometer scale. The focal position and frequency are tunable via the nanodot geometric shape and external bias magnetic fields. Attaching a narrow nanostripe to the focal region, the concentrated SW is efficiently coupled into the stripe and excites guided SW mode. Furthermore, by transversely shifting the focal point via a bias field, we selectively route SW to different attached nanostripes and even entirely suppress the injection, without modifying the structure. Our results enable sub-micrometer SW focusing, efficient injection, and dynamically reconfigurable multi-port routing within a compact nanodot array platform.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"642 ","pages":"Article 173901"},"PeriodicalIF":3.0,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146185907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-15Epub Date: 2026-01-29DOI: 10.1016/j.jmmm.2026.173873
Yanru Li , Meiyin Yang , Peiyue Yu , Shuaiyu Gong , Shuo Xu , Jingsong Huang , Baoshan Cui , Jinbiao Liu , Jun Luo
Spin-orbit-torque devices offer inherent advantages for reconfigurable and energy-efficient computing. However, spin logic schemes rely on hysteretic switching loops and therefore require state resetting, incurring additional power and area costs. Here, we demonstrate the non-resetting reconfigurable spin-orbit torque logic gates, including XOR, NOT, AND, OR and NAND logics. These logic gates are realized by non-hysteretic magnetization switching, which results from symmetry breaking, current induced Néel domain wall motion and all-linear magnetization switching mechanism at designed 0° and 90° lateral interfaces between ion implantation and non-implantation zones. Thanks to the non-hysteresis relationship between output and input during the current-induced magnetic switching, the proposed device in this work do not require resetting before each operation. This non-resetting reconfigurable SOT device holds great potential for high speed, low energy consumption and area-efficient logic-in-memory computation.
{"title":"Non-resetting spin logics based on non-hysteretic spin-orbit torque switching induced by the lateral interface","authors":"Yanru Li , Meiyin Yang , Peiyue Yu , Shuaiyu Gong , Shuo Xu , Jingsong Huang , Baoshan Cui , Jinbiao Liu , Jun Luo","doi":"10.1016/j.jmmm.2026.173873","DOIUrl":"10.1016/j.jmmm.2026.173873","url":null,"abstract":"<div><div>Spin-orbit-torque devices offer inherent advantages for reconfigurable and energy-efficient computing. However, spin logic schemes rely on hysteretic switching loops and therefore require state resetting, incurring additional power and area costs. Here, we demonstrate the non-resetting reconfigurable spin-orbit torque logic gates, including XOR, NOT, AND, OR and NAND logics. These logic gates are realized by non-hysteretic magnetization switching, which results from symmetry breaking, current induced Néel domain wall motion and all-linear magnetization switching mechanism at designed 0° and 90° lateral interfaces between ion implantation and non-implantation zones. Thanks to the non-hysteresis relationship between output and input during the current-induced magnetic switching, the proposed device in this work do not require resetting before each operation. This non-resetting reconfigurable SOT device holds great potential for high speed, low energy consumption and area-efficient logic-in-memory computation.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"642 ","pages":"Article 173873"},"PeriodicalIF":3.0,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146185929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this work, the BaFe11Ti0.5Al0.5O19 single crystals synthesized by spontaneous crystallization from solution were studied by scanning electron microscopy, X-ray powder diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, magnetic force microscopy, vibration magnetometry before and after 10 MeV electron irradiation with fluence of 1017 cm−2. It was found that irradiation leads to an insignificant relative increase in Fe2+ ions compared to Fe3+ ions. The modification of chemical bonds mainly on the surface of the BaFe11Ti0.5Al0.5O19 sample led to the distortion of the magnetic domain structure and an increase in magnetic anisotropy. This led to an increase in magnetic susceptibility in the range from 80 to 11,000 Oe, in the case when the magnetic field is directed along the sample surface. However, the modification of chemical bonds on the sample surface did not lead to changes in such parameters as saturation magnetization, coercivity, and remanent magnetization. Thus, significant degradation of the magnetic properties of the studied material BaFe11Ti0.5Al0.5O19 with electron irradiation is not observed.
{"title":"Magnetic properties of electron-irradiated BaFe11Ti0.5Al0.5O19 hexaferrite","authors":"A.D. Lobanov , Yu.V. Korkh , S.A. Maslova , D.A. Shishkin , N.A. Zhivulina , V.E. Zhivulin , S.A. Gudkova , D.A. Vinnik , E.I. Patrakov , S.G. Titova , M.N. Sarychev , R.G. Chumakov , V.Yu. Ivanov , T.V. Kuznetsova","doi":"10.1016/j.jmmm.2026.173885","DOIUrl":"10.1016/j.jmmm.2026.173885","url":null,"abstract":"<div><div>In this work, the BaFe<sub>11</sub>Ti<sub>0.5</sub>Al<sub>0.5</sub>O<sub>19</sub> single crystals synthesized by spontaneous crystallization from solution were studied by scanning electron microscopy, X-ray powder diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, magnetic force microscopy, vibration magnetometry before and after 10 MeV electron irradiation with fluence of 10<sup>17</sup> cm<sup>−2</sup>. It was found that irradiation leads to an insignificant relative increase in Fe<sup>2+</sup> ions compared to Fe<sup>3+</sup> ions. The modification of chemical bonds mainly on the surface of the BaFe<sub>11</sub>Ti<sub>0.5</sub>Al<sub>0.5</sub>O<sub>19</sub> sample led to the distortion of the magnetic domain structure and an increase in magnetic anisotropy. This led to an increase in magnetic susceptibility in the range from 80 to 11,000 Oe, in the case when the magnetic field is directed along the sample surface. However, the modification of chemical bonds on the sample surface did not lead to changes in such parameters as saturation magnetization, coercivity, and remanent magnetization. Thus, significant degradation of the magnetic properties of the studied material BaFe<sub>11</sub>Ti<sub>0.5</sub>Al<sub>0.5</sub>O<sub>19</sub> with electron irradiation is not observed.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"642 ","pages":"Article 173885"},"PeriodicalIF":3.0,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146185934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号