Pub Date : 2026-03-01Epub Date: 2026-01-10DOI: 10.1016/j.jmmm.2026.173828
Haonan Wang , Tianyi Li , Lei Wang , Xuling Han , Renjie Li , Mingjun Liu , Fei Wang , Changping Wang , Xiaolin Yan , Mingyue Ruan , Qiang Li
Double perovskite Gd2CrMnO6, characterized by strong 3d–4f exchange coupling and intrinsic B-site disorder, exhibits complex low-temperature magnetic behavior. We achieve effective magnetic-property tuning and a remarkable enhancement of the magnetocaloric effect (MCE) by controlling the grain size via high-energy ball milling. Structural analyses confirm that the orthorhombic Pbnm phase is preserved after milling. Magnetic susceptibility measurements reveal that decreasing grain size suppresses long-range antiferromagnetic (AFM) order while promoting surface ferromagnetic clusters, leading to the disappearance of Griffiths-like behavior in nanosized samples. ESR spectra of the 24 h-milled specimen display a single paramagnetic resonance with g ≈ 1.98, further evidencing the collapse of AFM order. The maximum magnetic-entropy change increases from 13.5 J kg−1 K−1 for the bulk to 21.1 J kg−1 K−1 at 7 T and 3 K after 24 h milling, without any detectable hysteresis. This remarkable enhancement arises from weakened AFM coupling and the increased density of weakly coupled surface spins, offering a viable pathway for optimizing cryogenic magnetic refrigeration in double perovskite oxides.
{"title":"Optimizing the magnetocaloric effect in Gd2CrMnO6 through controlled grain size reduction","authors":"Haonan Wang , Tianyi Li , Lei Wang , Xuling Han , Renjie Li , Mingjun Liu , Fei Wang , Changping Wang , Xiaolin Yan , Mingyue Ruan , Qiang Li","doi":"10.1016/j.jmmm.2026.173828","DOIUrl":"10.1016/j.jmmm.2026.173828","url":null,"abstract":"<div><div>Double perovskite Gd<sub>2</sub>CrMnO<sub>6</sub>, characterized by strong 3d–4f exchange coupling and intrinsic B-site disorder, exhibits complex low-temperature magnetic behavior. We achieve effective magnetic-property tuning and a remarkable enhancement of the magnetocaloric effect (MCE) by controlling the grain size via high-energy ball milling. Structural analyses confirm that the orthorhombic <em>Pbnm</em> phase is preserved after milling. Magnetic susceptibility measurements reveal that decreasing grain size suppresses long-range antiferromagnetic (AFM) order while promoting surface ferromagnetic clusters, leading to the disappearance of Griffiths-like behavior in nanosized samples. ESR spectra of the 24 h-milled specimen display a single paramagnetic resonance with g ≈ 1.98, further evidencing the collapse of AFM order. The maximum magnetic-entropy change increases from 13.5 J kg<sup>−1</sup> K<sup>−1</sup> for the bulk to 21.1 J kg<sup>−1</sup> K<sup>−1</sup> at 7 T and 3 K after 24 h milling, without any detectable hysteresis. This remarkable enhancement arises from weakened AFM coupling and the increased density of weakly coupled surface spins, offering a viable pathway for optimizing cryogenic magnetic refrigeration in double perovskite oxides.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"641 ","pages":"Article 173828"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145975171","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 : 2026-03-01Epub Date: 2026-01-17DOI: 10.1016/j.jmmm.2026.173857
M. Stella , V. Bertolini , G. Carlotti , A. Faba
For CubeSat nanosatellites, rapid attitude stabilization after orbital deployment is critical for mission success. In this work, we optimize the geometry of hysteresis materials to maximize the dissipation of rotational kinetic energy. We developed an analytical–computational method to compare cylindrical rods and ellipsoids, using experimental data from an additively manufactured Fe–Si 3.7 wt% Si alloy. After optimizing a cylinder’s diameter via Finite Element (FE) simulations, we used its volume as a constraint for the analytical optimization of an ellipsoid. The results, validated by further FE simulations, indicate that ellipsoids yield superior energy losses. Specifically, the optimized ellipsoidal geometry showed a 28% increase in losses. This improvement leads to a significant reduction in attitude stabilization time of approximately 2 days, establishing ellipsoids as the preferable choice for designing compact and efficient passive magnetic attitude control systems.
{"title":"Analytical and computational geometry optimization for nanosatellites magnetic damping systems","authors":"M. Stella , V. Bertolini , G. Carlotti , A. Faba","doi":"10.1016/j.jmmm.2026.173857","DOIUrl":"10.1016/j.jmmm.2026.173857","url":null,"abstract":"<div><div>For CubeSat nanosatellites, rapid attitude stabilization after orbital deployment is critical for mission success. In this work, we optimize the geometry of hysteresis materials to maximize the dissipation of rotational kinetic energy. We developed an analytical–computational method to compare cylindrical rods and ellipsoids, using experimental data from an additively manufactured Fe–Si 3.7 wt% Si alloy. After optimizing a cylinder’s diameter via Finite Element (FE) simulations, we used its volume as a constraint for the analytical optimization of an ellipsoid. The results, validated by further FE simulations, indicate that ellipsoids yield superior energy losses. Specifically, the optimized ellipsoidal geometry showed a 28% increase in losses. This improvement leads to a significant reduction in attitude stabilization time of approximately 2 days, establishing ellipsoids as the preferable choice for designing compact and efficient passive magnetic attitude control systems.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"641 ","pages":"Article 173857"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035299","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 : 2026-03-01Epub Date: 2026-01-14DOI: 10.1016/j.jmmm.2026.173827
J.M. Martínez , J.M. Nieto-Jalil , A. Lobo Guerrero , J.H. García Gallegos
We present a fast magnetometry route to quantify dipolar mean-field coupling and recover the intrinsic switching-field distribution (iSFD) using only a major hysteresis loop plus the initial magnetization curve acquired from an AC-demagnetized state. Within a Stoner–Wohlfarth/Preisach mean-field picture, interaction-induced shearing broadens susceptibilities; α is obtained from area identities at high remanence and, for low-remanence systems, from an offset-free derivative estimator. Validation on Sr-hexaferrite nanoparticles embedded in PVA nanofibers yields and − 840 Oe for 1.5%, 2.0% and 2.5% loadings, respectively, and deshearing collapses loops and susceptibilities onto their intrinsic references. The workflow includes two internal consistency checks, post-deshearing antisymmetry of branches and initial-curve/upper-branch overlap for , making the estimate auditable. Compared to /Henkel and FORC, the method requires a single loop plus one initial curve and remains robust in the presence of reversible contributions.
{"title":"Quantifying dipolar mean-field interactions from hysteresis and initial curves: A fast Magnetometry route to iSFD Deshearing","authors":"J.M. Martínez , J.M. Nieto-Jalil , A. Lobo Guerrero , J.H. García Gallegos","doi":"10.1016/j.jmmm.2026.173827","DOIUrl":"10.1016/j.jmmm.2026.173827","url":null,"abstract":"<div><div>We present a fast magnetometry route to quantify dipolar mean-field coupling <span><math><mfenced><mi>α</mi></mfenced></math></span> and recover the intrinsic switching-field distribution (iSFD) using only a major hysteresis loop plus the initial magnetization curve acquired from an AC-demagnetized state. Within a Stoner–Wohlfarth/Preisach mean-field picture, interaction-induced shearing broadens susceptibilities; α is obtained from area identities at high remanence and, for low-remanence systems, from an offset-free derivative estimator. Validation on Sr-hexaferrite nanoparticles embedded in PVA nanofibers yields <span><math><mi>α</mi><mo>≈</mo><mo>−</mo><mn>535</mn><mo>,</mo><mo>−</mo><mn>740</mn></math></span> and − 840 Oe for 1.5%, 2.0% and 2.5% loadings, respectively, and deshearing collapses loops and susceptibilities onto their intrinsic references. The workflow includes two internal consistency checks, post-deshearing antisymmetry of branches and initial-curve/upper-branch overlap for <span><math><mi>H</mi><mo>≥</mo><mn>0</mn></math></span>, making the estimate auditable. Compared to <span><math><mi>Δ</mi><mi>M</mi></math></span>/Henkel and FORC, the method requires a single loop plus one initial curve and remains robust in the presence of reversible contributions.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"641 ","pages":"Article 173827"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073680","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 : 2026-03-01Epub Date: 2026-01-24DOI: 10.1016/j.jmmm.2026.173860
N. Bouzakraoui , A. Samih , R. El Fdil , Z. Fadil , E. Salmani , Chaitany Jayprakash Raorane , Seong-Cheol Kim , S. Saadaoui
This work examines the structural, mechanical, electronic, magnetic, optical, and thermodynamic properties of CoCrTe and NiVTe half-Heusler alloys. Stability analysis identifies the β-configuration (X at 4c, Y at 4a, and Z at 4b) as the most favorable structure. Both compounds are thermodynamically stable, as confirmed by negative formation energies and convex hull analysis. Their mechanical and dynamical stability is further verified through elastic constants and phonon spectra. Electronic structure and magnetic properties are investigated using the GGA-PBE and meta-GGA-SCAN functionals to better describe the strongly correlated 3d states. The results reveal that both CoCrTe and NiVTe are ferromagnetic half-metals with a total magnetic moment of 3 μB, consistent with the Slater–Pauling rule, highlighting their potential for spintronic applications. Optical calculations indicate promising performance in infrared and ultraviolet optoelectronic devices. Finally, thermodynamic analysis demonstrates that both alloys possess excellent thermal stability.
{"title":"Comprehensive DFT study of CoCrTe and NiVTe half-Heuslers: Structure, magnetism, and optical response","authors":"N. Bouzakraoui , A. Samih , R. El Fdil , Z. Fadil , E. Salmani , Chaitany Jayprakash Raorane , Seong-Cheol Kim , S. Saadaoui","doi":"10.1016/j.jmmm.2026.173860","DOIUrl":"10.1016/j.jmmm.2026.173860","url":null,"abstract":"<div><div>This work examines the structural, mechanical, electronic, magnetic, optical, and thermodynamic properties of CoCrTe and NiVTe half-Heusler alloys. Stability analysis identifies the β-configuration (X at 4c, Y at 4a, and Z at 4b) as the most favorable structure. Both compounds are thermodynamically stable, as confirmed by negative formation energies and convex hull analysis. Their mechanical and dynamical stability is further verified through elastic constants and phonon spectra. Electronic structure and magnetic properties are investigated using the GGA-PBE and meta-GGA-SCAN functionals to better describe the strongly correlated 3d states. The results reveal that both CoCrTe and NiVTe are ferromagnetic half-metals with a total magnetic moment of 3 μ<sub>B</sub>, consistent with the Slater–Pauling rule, highlighting their potential for spintronic applications. Optical calculations indicate promising performance in infrared and ultraviolet optoelectronic devices. Finally, thermodynamic analysis demonstrates that both alloys possess excellent thermal stability.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"641 ","pages":"Article 173860"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073682","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 : 2026-03-01Epub Date: 2026-01-16DOI: 10.1016/j.jmmm.2026.173848
A. El Boubekri , M. Sajieddine , M. Lassri , M. Sahlaoui , A. Razouk , H. Lassri , A. Essoumhi
Amorphous alloys with the composition Fe78−xCr2+xSi8B12 (x = 0–10 at. %) were produced by rapid quenching melt-spinning. X-ray diffraction confirmed their fully amorphous nature, while thermal analysis revealed glass transition and crystallization events, with the onset of crystallization shifting to higher temperatures as chromium content increased. Scanning electron microscopy showed uniform and defect-free surfaces, confirming compositional homogeneity across all samples. At the atomic scale, 57Fe Mössbauer spectroscopy provided insights into the local magnetic environment. The spectra exhibited broad and bimodal hyperfine field distributions, reflecting two of atomic surroundings: Fe-rich clusters and regions diluted by Cr, Si, and B. Increasing Cr content progressively reduced both the average hyperfine field and the Fe magnetic moment. These microscopic trends were echoed in bulk magnetic behavior. Hysteresis loops revealed soft ferromagnetic characteristics with low coercivity, and the saturation magnetization closely followed the Mössbauer-derived Fe moments. The correlations between local atomic order and magnetism highlight the dual role of chromium: it stabilizes the amorphous structure while tuning magnetic softness.
{"title":"Mössbauer study and magnetic properties of Fe78-xCr2+xSi8B12 amorphous ribbons","authors":"A. El Boubekri , M. Sajieddine , M. Lassri , M. Sahlaoui , A. Razouk , H. Lassri , A. Essoumhi","doi":"10.1016/j.jmmm.2026.173848","DOIUrl":"10.1016/j.jmmm.2026.173848","url":null,"abstract":"<div><div>Amorphous alloys with the composition Fe<sub>78−x</sub>Cr<sub>2+x</sub>Si<sub>8</sub>B<sub>12</sub> (<em>x</em> = 0–10 at. %) were produced by rapid quenching melt-spinning. X-ray diffraction confirmed their fully amorphous nature, while thermal analysis revealed glass transition and crystallization events, with the onset of crystallization shifting to higher temperatures as chromium content increased. Scanning electron microscopy showed uniform and defect-free surfaces, confirming compositional homogeneity across all samples. At the atomic scale, <sup>57</sup>Fe Mössbauer spectroscopy provided insights into the local magnetic environment. The spectra exhibited broad and bimodal hyperfine field distributions, reflecting two of atomic surroundings: Fe-rich clusters and regions diluted by Cr, Si, and B. Increasing Cr content progressively reduced both the average hyperfine field and the Fe magnetic moment. These microscopic trends were echoed in bulk magnetic behavior. Hysteresis loops revealed soft ferromagnetic characteristics with low coercivity, and the saturation magnetization closely followed the Mössbauer-derived Fe moments. The correlations between local atomic order and magnetism highlight the dual role of chromium: it stabilizes the amorphous structure while tuning magnetic softness.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"641 ","pages":"Article 173848"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035347","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 : 2026-03-01Epub Date: 2026-01-14DOI: 10.1016/j.jmmm.2026.173839
Zhixin Shu , Jiaying Jin , Liang Zhou , Boyu Li , Jifei Hong , Dong Ma , Wang Chen , Mi Yan
High-Ce-substituted Nd-Ce-Fe-B permanent magnets offer a cost-effective solution but are limited by magnetic dilution and microstructural degradation. This study specifically investigates the Ce-75 sintered magnets (Ce/total rare earth = 75 wt%) using a dual-modification approach that combines the intergranular addition of (Nd, Pr)Hx and (Nd, Pr)90Dy10Hx with optimized two-step annealing. The 4 wt% (Nd, Pr)Hx-modified magnet achieves a 54% coercivity improvement from 5.48 to 8.45 kOe via the formation of Nd/Pr-rich shell. More remarkably, the 4 wt% (Nd, Pr)90Dy10Hx-modified counterpart demonstrates a 90% enhancement from 5.48 to 10.36 kOe with minimal remanence sacrifice, attributed to synergistic effects of Dy-rich grain shells coupled with Nd/Pr-rich grain boundaries. These findings demonstrate the significance of controlled elemental spatial distribution for achieving simultaneous coercivity enhancement and efficient rare earth utilization.
{"title":"Enhanced coercivity in high-Ce-substituted Nd-Ce-Fe-B magnets via intergranular addition and optimized annealing","authors":"Zhixin Shu , Jiaying Jin , Liang Zhou , Boyu Li , Jifei Hong , Dong Ma , Wang Chen , Mi Yan","doi":"10.1016/j.jmmm.2026.173839","DOIUrl":"10.1016/j.jmmm.2026.173839","url":null,"abstract":"<div><div>High-Ce-substituted Nd-Ce-Fe-B permanent magnets offer a cost-effective solution but are limited by magnetic dilution and microstructural degradation. This study specifically investigates the Ce-75 sintered magnets (Ce/total rare earth = 75 wt%) using a dual-modification approach that combines the intergranular addition of (Nd, Pr)H<sub>x</sub> and (Nd, Pr)<sub>90</sub>Dy<sub>10</sub>H<sub>x</sub> with optimized two-step annealing. The 4 wt% (Nd, Pr)H<sub>x</sub>-modified magnet achieves a 54% coercivity improvement from 5.48 to 8.45 kOe via the formation of Nd/Pr-rich shell. More remarkably, the 4 wt% (Nd, Pr)<sub>90</sub>Dy<sub>10</sub>H<sub>x</sub>-modified counterpart demonstrates a 90% enhancement from 5.48 to 10.36 kOe with minimal remanence sacrifice, attributed to synergistic effects of Dy-rich grain shells coupled with Nd/Pr-rich grain boundaries. These findings demonstrate the significance of controlled elemental spatial distribution for achieving simultaneous coercivity enhancement and efficient rare earth utilization.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"641 ","pages":"Article 173839"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035354","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 : 2026-03-01Epub Date: 2026-01-06DOI: 10.1016/j.jmmm.2026.173815
Zhengang Zhao , Kuisong Yang , Junjiang Shi , Yinjie Hou , Chuan Luo
In this paper, we propose and design a novel fluxgate current sensor with low inter-coil coupling. The design has an openable structure that allows rapid installation and removal without interrupting the circuit. The design achieves a closed rectangular magnetic core by optimizing a parallel dual-core configuration. The physical separation between the excitation flux and the induction path enables the formation of a closed magnetic circuit and the implementation of low-coupling coil arrangements, effectively suppressing electromagnetic interference while maintaining strong flux modulation capability. The operational principle of the sensor probe is first derived analytically, followed by the development of a finite element simulation model of the fluxgate probe. The magnetic coupling characteristics of sensors employing two distinct winding configurations are compared and analyzed, and two prototypes are fabricated and tested for performance evaluation. Experimental results indicate that the sensor with the proposed low inter-coil coupling structure has a linearity error of 0.169 %, a repeatability of 0.154 %, a sensitivity of 0.260 V/A. The overall absolute error is less than 8.5 mV, while the offset drift is 3.24 mV. Furthermore, the sensor exhibits a measurement uncertainty of 0.307 % within a DC current range of ±10 A. This study provides novel insights into the design of high-performance, high-stability fluxgate current sensors, highlighting their potential for a wide range of engineering applications.
{"title":"Design of an openable structure fluxgate current sensor with low inter-coil coupling","authors":"Zhengang Zhao , Kuisong Yang , Junjiang Shi , Yinjie Hou , Chuan Luo","doi":"10.1016/j.jmmm.2026.173815","DOIUrl":"10.1016/j.jmmm.2026.173815","url":null,"abstract":"<div><div>In this paper, we propose and design a novel fluxgate current sensor with low inter-coil coupling. The design has an openable structure that allows rapid installation and removal without interrupting the circuit. The design achieves a closed rectangular magnetic core by optimizing a parallel dual-core configuration. The physical separation between the excitation flux and the induction path enables the formation of a closed magnetic circuit and the implementation of low-coupling coil arrangements, effectively suppressing electromagnetic interference while maintaining strong flux modulation capability. The operational principle of the sensor probe is first derived analytically, followed by the development of a finite element simulation model of the fluxgate probe. The magnetic coupling characteristics of sensors employing two distinct winding configurations are compared and analyzed, and two prototypes are fabricated and tested for performance evaluation. Experimental results indicate that the sensor with the proposed low inter-coil coupling structure has a linearity error of 0.169 %, a repeatability of 0.154 %, a sensitivity of 0.260 V/A. The overall absolute error is less than 8.5 mV, while the offset drift is 3.24 mV. Furthermore, the sensor exhibits a measurement uncertainty of 0.307 % within a DC current range of ±10 A. This study provides novel insights into the design of high-performance, high-stability fluxgate current sensors, highlighting their potential for a wide range of engineering applications<strong>.</strong></div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"641 ","pages":"Article 173815"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145908883","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 : 2026-03-01Epub Date: 2026-01-09DOI: 10.1016/j.jmmm.2026.173825
Connor J. Wood, Robert E. Camley
We analyze the nonlinear behavior of two ferromagnetic films which are antiferromagnetically coupled. The resulting equations are solved numerically to determine what would be measured in magnetic resonance or pulse inductive microwave magnetometry experiments. We find a strong, power-dependent, hysteresis in the resonant absorption that is dependent on whether one scans upwards or downwards in frequency, which can extend over 14 GHz in some cases. We show that the hysteretic behavior is due to a dynamically modified canting angle that deviates from the equilibrium value found for the linear solutions. In addition, we look at the spectral decomposition to analyze how energy is transformed. For nonlinear modes, we find major differences between the driving frequency and the frequencies of the resonance modes which are ultimately created. This includes a down-conversion from a 13.5 GHz driving signal to a 1.5 GHz resonance frequency, as well as half frequency responses. Our synchronization studies dramatically illustrate the limits of the linear and nonlinear regions in terms of initial amplitudes and time evolution of the correlation between the two films moments.
{"title":"Nonlinear resonance in antiferromagnetically coupled magnetic bilayers: Hysteresis, spectral response, and synchronization","authors":"Connor J. Wood, Robert E. Camley","doi":"10.1016/j.jmmm.2026.173825","DOIUrl":"10.1016/j.jmmm.2026.173825","url":null,"abstract":"<div><div>We analyze the nonlinear behavior of two ferromagnetic films which are antiferromagnetically coupled. The resulting equations are solved numerically to determine what would be measured in magnetic resonance or pulse inductive microwave magnetometry experiments. We find a strong, power-dependent, hysteresis in the resonant absorption that is dependent on whether one scans upwards or downwards in frequency, which can extend over 14 GHz in some cases. We show that the hysteretic behavior is due to a dynamically modified canting angle that deviates from the equilibrium value found for the linear solutions. In addition, we look at the spectral decomposition to analyze how energy is transformed. For nonlinear modes, we find major differences between the driving frequency and the frequencies of the resonance modes which are ultimately created. This includes a down-conversion from a 13.5 GHz driving signal to a 1.5 GHz resonance frequency, as well as half frequency responses. Our synchronization studies dramatically illustrate the limits of the linear and nonlinear regions in terms of initial amplitudes and time evolution of the correlation between the two films moments.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"641 ","pages":"Article 173825"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145975214","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 investigate the nonlinear spin dynamics of a frustrated Kagomé lattice subjected to a time-periodic magnetic field, focusing on the effects of Dzyaloshinskii–Moriya interaction (DMI), magnetic anisotropy and exchange coupling. Using numerical simulations of the Landau–Lifshitz–Gilbert equation, we analyze the evolution of spin oscillations via Poincaré surface sections and power spectral density across a wide parameter range. At low DMI, weak anisotropy, and small external field strengths, the system exhibits quasi-periodic oscillations governed primarily by exchange interactions. Increasing the DMI strength induces strong aperiodic behavior, with a clear transition to chaotic dynamics, particularly under moderate anisotropy. While strong easy-axis anisotropy tends to stabilize periodic orbits, sufficiently strong DMI can still drive the system into chaos. Furthermore, we show that external fields destabilize oscillations in weakly anisotropic regimes but have limited impact in the presence of strong anisotropy. We also compute the magnon dispersion relation and magnetic resonance (MR) spectra, revealing multi-peak structures at high DMI which indicate the presence of strong nonlinear spin-wave interactions. Our results highlight the critical role of DMI and anisotropy in shaping dynamical responses in Kagomé magnets, affecting the development of spintronic and magnonic devices.
{"title":"Nonlinearity in spin dynamics of frustrated Kagomé lattice system under harmonic perturbation","authors":"Saumen Acharjee, Arindam Boruah, Reeta Devi, Nimisha Dutta","doi":"10.1016/j.jmmm.2026.173852","DOIUrl":"10.1016/j.jmmm.2026.173852","url":null,"abstract":"<div><div>We investigate the nonlinear spin dynamics of a frustrated Kagomé lattice subjected to a time-periodic magnetic field, focusing on the effects of Dzyaloshinskii–Moriya interaction (DMI), magnetic anisotropy and exchange coupling. Using numerical simulations of the Landau–Lifshitz–Gilbert equation, we analyze the evolution of spin oscillations via Poincaré surface sections and power spectral density across a wide parameter range. At low DMI, weak anisotropy, and small external field strengths, the system exhibits quasi-periodic oscillations governed primarily by exchange interactions. Increasing the DMI strength induces strong aperiodic behavior, with a clear transition to chaotic dynamics, particularly under moderate anisotropy. While strong easy-axis anisotropy tends to stabilize periodic orbits, sufficiently strong DMI can still drive the system into chaos. Furthermore, we show that external fields destabilize oscillations in weakly anisotropic regimes but have limited impact in the presence of strong anisotropy. We also compute the magnon dispersion relation and magnetic resonance (MR) spectra, revealing multi-peak structures at high DMI which indicate the presence of strong nonlinear spin-wave interactions. Our results highlight the critical role of DMI and anisotropy in shaping dynamical responses in Kagomé magnets, affecting the development of spintronic and magnonic devices.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"641 ","pages":"Article 173852"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035355","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 : 2026-03-01Epub Date: 2026-01-08DOI: 10.1016/j.jmmm.2025.173768
Amal Homri , Jose Ordonez-Miranda , Ouissem Jalled , Jemai Dhahri , Jean Juraszek
A novel multi-cation substituted M-type hexaferrite, BaFe11.6Mg0.05Mn0.05Ti0.2Ni0.1O19 (BFMMTNO), was synthesized via the conventional solid-state route and sintered at high temperature to explore its structural, morphological, magnetic, and magnetocaloric properties. The partial replacement of Fe3+ ions with Mg2+, Mn2+, Ni2+, and Ti4+ was designed to tailor magnetic anisotropy and enhance magnetic performance. X-ray diffraction confirmed the formation of a single-phase hexagonal magnetoplumbite structure with high crystallinity and an average crystallite size of 87 nm. SEM, TEM, and HR-TEM analyses revealed well-defined grains and excellent lattice ordering. Raman spectroscopy detected subtle lattice distortions arising from multi-site cation substitution, reflecting its influence on the magnetic framework.
Mössbauer spectroscopy further confirmed the redistribution of Fe3+ ions among the crystallographic sites and revealed a significant reduction in hyperfine magnetic fields induced by multi-cation substitution. Magnetic characterization demonstrated a coercivity of 2.26 kOe, a strong magnetocrystalline anisotropy constant of 7.81 × 105 erg/cm3, and a saturation magnetization of 69.36 emu/g. The compound also exhibited promising magnetocaloric behavior, with a maximum magnetic entropy change (ΔSₘ) of 2.43 J/kg·K and a relative cooling power (RCP) of ∼187 J/kg.
These findings highlight the effectiveness of multi-cation substitution in tuning the structural and magnetic properties of M-type hexaferrites, underscoring their potential for advanced solid-state magnetic refrigeration applications.
{"title":"Structural, magnetic, and magnetocaloric performance of BaFe11.6Mg0.05Mn0.05Ti0.2Ni0.1O19 M type hexaferrite","authors":"Amal Homri , Jose Ordonez-Miranda , Ouissem Jalled , Jemai Dhahri , Jean Juraszek","doi":"10.1016/j.jmmm.2025.173768","DOIUrl":"10.1016/j.jmmm.2025.173768","url":null,"abstract":"<div><div>A novel multi-cation substituted M-type hexaferrite, BaFe<sub>11.6</sub>Mg<sub>0.05</sub>Mn<sub>0.05</sub>Ti<sub>0.2</sub>Ni<sub>0.1</sub>O<sub>19</sub> (BFMMTNO), was synthesized via the conventional solid-state route and sintered at high temperature to explore its structural, morphological, magnetic, and magnetocaloric properties. The partial replacement of Fe<sup>3+</sup> ions with Mg<sup>2+</sup>, Mn<sup>2+</sup>, Ni<sup>2+</sup>, and Ti<sup>4+</sup> was designed to tailor magnetic anisotropy and enhance magnetic performance. X-ray diffraction confirmed the formation of a single-phase hexagonal magnetoplumbite structure with high crystallinity and an average crystallite size of 87 nm. SEM, TEM, and HR-TEM analyses revealed well-defined grains and excellent lattice ordering. Raman spectroscopy detected subtle lattice distortions arising from multi-site cation substitution, reflecting its influence on the magnetic framework.</div><div>Mössbauer spectroscopy further confirmed the redistribution of Fe<sup>3+</sup> ions among the crystallographic sites and revealed a significant reduction in hyperfine magnetic fields induced by multi-cation substitution. Magnetic characterization demonstrated a coercivity of 2.26 kOe, a strong magnetocrystalline anisotropy constant of 7.81 × 10<sup>5</sup> erg/cm<sup>3</sup>, and a saturation magnetization of 69.36 emu/g. The compound also exhibited promising magnetocaloric behavior, with a maximum magnetic entropy change (ΔSₘ) of 2.43 J/kg·K and a relative cooling power (RCP) of ∼187 J/kg.</div><div>These findings highlight the effectiveness of multi-cation substitution in tuning the structural and magnetic properties of M-type hexaferrites, underscoring their potential for advanced solid-state magnetic refrigeration applications.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"641 ","pages":"Article 173768"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073681","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}
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