Journal of Magnetism and Magnetic Materials最新文献

{"title":"Effects of Zr doping on the microstructure and magnetic properties of Nd-Fe-B-Ga sintered magnet","authors":"Song Fu ,&nbsp;Yijian Ji ,&nbsp;Jie Song ,&nbsp;Xiaolian Liu ,&nbsp;Shuainan Xu ,&nbsp;Lizhong Zhao ,&nbsp;Yu Pan ,&nbsp;Pengfei Guan ,&nbsp;Xuefeng Zhang","doi":"10.1016/j.jmmm.2025.173462","DOIUrl":"10.1016/j.jmmm.2025.173462","url":null,"abstract":"<div><div>To address the growing demand for high-coercivity Nd-Fe-B sintered magnets, the effects of Zr doping on the microstructural evolution and magnetic properties of Ga-containing Nd-Fe-B magnets with a normal level of B content are systematically investigated. With the increase of Zr content to 0.5 wt%, the coercivity is enhanced significantly with a superior squareness of 99 %. While after Zr addition to 1.0 wt%, despite the Zr-B precipitates increase, the coercivity has slightly decreased instead. Through microstructural characterizations, the Zr-containing precipitates include cluster-like ZrB₂, granulate Zr₂Fe (<em>I4/mcm</em>) and square ZrB (<em>Fm</em> <span><math><mrow><mover><mrow><mn>3</mn></mrow><mrow><mo>¯</mo></mrow></mover></mrow></math></span> <em>m</em>) phases. The local B-lean chemistry by Zr-B precipitation promotes the formation of anti-ferromagnetic Nd₆Fe₁₃Ga phase during post-sinter annealing process, resulting in a decrease in the Fe content of Nd-rich phases, enhancing magnetic decoupling and improving the coercivity. However, excessive Zr doping (1.0 wt%) reduces the volume fraction of Nd₂Fe₁₄B phase, increases Fe content of Nd-rich phases and then promotes the formation of ferromagnetic Nd₆Fe₁₃Ga phase during annealing, as detected by Lorentz TEM. The ferromagnetic Nd₆Fe₁₃Ga phase with relatively higher Fe content when Nd vacancy forms at <em>8f</em> site is further confirmed by first-principles calculations. The presence of ferromagnetic Nd₆Fe₁₃Ga phase impedes the further coercivity enhancement, as the continuous grain refinement fails to offset the weakened magnetic decouple effect. These findings demonstrate that strategic Zr doping to regulate Nd₆Fe₁₃Ga phase represents a promising approach for optimizing the magnetic properties of Ga-containing Nd-Fe-B sintered magnets.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"630 ","pages":"Article 173462"},"PeriodicalIF":3.0,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144896343","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}

{"title":"Quantifying time in Monte Carlo simulations: Application to relaxation processes and AC susceptibilities of magnetic nanoparticles assemblies","authors":"A. Morjane ,&nbsp;J.-G. Malherbe ,&nbsp;Juan J. Alonso ,&nbsp;F. Vernay ,&nbsp;V. Russier","doi":"10.1016/j.jmmm.2025.173443","DOIUrl":"10.1016/j.jmmm.2025.173443","url":null,"abstract":"<div><div>The study of the response of magnetic nanoparticles (MNP) assemblies to an external alternating magnetic field is of great interest for applications such as hyperthermia. The key quantity here is the complex susceptibility and its behavior in terms of temperature and frequency. From a theoretical point of view it can be obtained by Monte Carlo (MC) simulation with the time quantified Monte Carlo (TQMC) method if a physical time is associated with the MC step. Here we revisit this method by showing that the time unit can be derived from the MC stochastic process of the isolated particle. We first obtain a MC unit of time from the relaxation of the system at fixed temperature. Then this unit of time is used to compute complex susceptibilities. We show that it is now possible to match the TQMC results with actual experimental results regarding frequency dependent in phase susceptibilities and quantify the unit of time in seconds. Finally we show that the time unit obtained for the isolated particle remains valid when considering interacting particles such as the Heisenberg coupling or dipole dipole interactions.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"630 ","pages":"Article 173443"},"PeriodicalIF":3.0,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144903866","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}

{"title":"An elemental modelling method for linear motor parametric studies using boundary-free analytic magnetic field solutions: Including 3D geometry, permeability, and end effects","authors":"Matthew Forbes ,&nbsp;William S.P. Robertson ,&nbsp;Anthony C. Zander ,&nbsp;Johannes J.H. Paulides","doi":"10.1016/j.jmmm.2025.173416","DOIUrl":"10.1016/j.jmmm.2025.173416","url":null,"abstract":"<div><div>In this article we highlight an Elemental Modelling Method, as an alternative to the standard Harmonic (or Fourier) Model, that can include variable permeability and non-periodic 3D geometry with superposition of boundary-free analytic magnetic field solutions. The methodology is demonstrated with an exhaustive parametric search to optimise a set of tubular double-sided Halbach slotless permanent magnet linear synchronous motor topologies, within a fixed volume constraint. The modelling method is computationally efficient, facilitating the search of close to 900,000 topologies with an axisymmetric-2D assumption, subsequently converted to a full 3D design. The aim of this study is to investigate the effect of strategic addition of iron within the topologies, against the trade-off of reducing permanent magnet volume — such an analysis is not simple, or possible, within the Harmonic Model. The elements of the model include coil filaments, permanent magnets, and iron segments inclusive of saturation effects from nonlinear permeability. A design with inset permanent magnets and surface iron found in the parametric search is shown to outperform the optimal Halbach topologies, with improved figures of merit for force and force ripple with low phase currents. Results are compared with Finite Element Analysis and performance of a design with non-unity relative permeability of the permanent magnets is assessed.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"630 ","pages":"Article 173416"},"PeriodicalIF":3.0,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144903871","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}

{"title":"Research on optimization of the spatial composite magnetic field magnetic needle abrasive grinding process based on CFD-DEM coupling","authors":"Xiaotong Xu ,&nbsp;Qiushi Shen ,&nbsp;Bing Han ,&nbsp;Jiabin Tang ,&nbsp;Jun Ying ,&nbsp;Haiji Yang","doi":"10.1016/j.jmmm.2025.173458","DOIUrl":"10.1016/j.jmmm.2025.173458","url":null,"abstract":"<div><div>To expand the effective processing area of magnetic needle abrasive grinding (MNAG) finishing technology and enhance the uniformity of workpiece surface morphology, this study proposes a magnetic needle abrasive grinding finishing method based on a spatial composite magnetic field. By constructing a spatial composite magnetic field, the magnetic field distribution range within the processing area is effectively broadened. Non-equal-sized magnetic poles are designed to intensify the magnetic field gradient, which is verified through COMSOL simulations, thereby enabling the formation of a spatially composite magnetic field. A CFD-DEM multi-field coupling model of magnetohydrodynamics and solid mechanics was established to study the distribution characteristics and movement trajectories of magnetic needle particles during the magnetic needle abrasive grinding process under the influence of a spatial composite magnetic field, as well as their impact on the cumulative contact energy of the workpiece surface. Finally, a magnetic abrasive polishing device equipped with a spatial composite magnetic field is developed. The accuracy of the simulation results is validated through comparative analysis of surface morphologies obtained under conditions with and without auxiliary magnetic poles. Experimental results demonstrate that magnetic needle abrasive grinding under a spatial composite magnetic field can significantly extend the processing range, increase the height of the effective processing area by 200%, and improve the uniformity of the workpiece surface morphology.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"630 ","pages":"Article 173458"},"PeriodicalIF":3.0,"publicationDate":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144903868","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}

{"title":"Investigation of the combined microscopic and macroscopic conditions of magnetic fluids’ magnetoviscous effects at high shear rates in narrow sealing channels","authors":"Xueqi Wang ,&nbsp;Yibiao Chen ,&nbsp;Lei Yang ,&nbsp;Decai Li ,&nbsp;Hongming Zhou","doi":"10.1016/j.jmmm.2025.173451","DOIUrl":"10.1016/j.jmmm.2025.173451","url":null,"abstract":"<div><div>Magnetic fluids combine magnetic responsiveness with fluidic characteristics, making them widely used in seals, dampers, and optical devices. However, magnetic fluids currently suffer from unique magnetoviscous effects such as nonlinear changes in viscosity at high shear rates in the narrow channel of a seal. This effect is directly related to the heating of the seal and affects the reliability of the seal. Therefore, for the special case of high shear rates within a narrow channel with a sealed gap, this paper explores the mechanism of the magnetic fluid’s microstructure on the magnetoviscous effect at both the microscopic and macroscopic levels. The computational stress equation of the microscopic system is derived, the simulation model of chain formation and breakage of magnetic particles at high shear rates is established, and the magnetic fluids’ rheological characteristics at high shear rates in the narrow channel are obtained by viscosity simulation and rheometer measurements. The viscosity of the magnetic fluids decreases significantly at elevated shear rates, exhibiting shear thinning. In the weak magnetic field, magnetic field enhancement strengthens the magnetoviscous effect; in the strong magnetic field, magnetic field enhancement shows the magnetic viscosity drop effect. The results of the studies provide a theoretical base for the preparation of magnetic fluids for sealing, which is significant for broadening the application fields of magnetic fluids.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"630 ","pages":"Article 173451"},"PeriodicalIF":3.0,"publicationDate":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144903870","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}

{"title":"First principles study of magnetic anisotropy in FePt/SrTiO3 heterostructure","authors":"YingXin Wang,&nbsp;JiaWei He,&nbsp;Bo Chen,&nbsp;YongMei Zhang","doi":"10.1016/j.jmmm.2025.173455","DOIUrl":"10.1016/j.jmmm.2025.173455","url":null,"abstract":"<div><div>This work studies the magnetic property of <em>L</em>1₀-phase FePt film bonding to SrTiO₃ substrate. Two different FePt/STO heterostructure with FePt/SrO-STO and FePt/TiO-STO interface were designed, by bonding SrTiO₃ substrates with SrO and TiO surfaces to FePt film respectively. The density distribution of electron state, electronic occupation number, charge density difference, magnetic moment, and magnetic anisotropy energy were studied by first-principles calculations. Comparing these results before and after the bonding the substrate, the magnetic anisotropy energy on FePt/SrO-STO and FePt/TiO-STO interface are both influenced by the STO substrate. Furthermore, the decrease of magnetic anisotropy energy is more obvious on FePt/SrO-STO interface than that on FePt/TiO-STO interface. It is due to the complex orbital hybridization and electron transfer on the FePt/STO interface, which changes the density distribution and electron occupancy of d orbital state for Fe atoms. This paper deeply analyzes the magnetic property of <em>L</em>1₀-phase FePt film bonding on STO substrate, through the atomic level. It provides new way to control the MAE of hard magnetic film, which will help develop new semiconductor functional devices.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"630 ","pages":"Article 173455"},"PeriodicalIF":3.0,"publicationDate":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144893559","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}

{"title":"Piezomagnetic reversal behavior of anisotropic wire arc additively manufactured steel under tensile stress","authors":"Sheng Bao,&nbsp;Yan Li,&nbsp;Jingxuan Hong","doi":"10.1016/j.jmmm.2025.173452","DOIUrl":"10.1016/j.jmmm.2025.173452","url":null,"abstract":"<div><div>In this research, the piezomagnetic reversal behavior of anisotropic steel under tensile stress in different directions was investigated. Tensile tests were performed on wire and arc additively manufactured (WAAM) steel specimens with varying orientations relative to the deposition direction, using a stepwise loading protocol. Magnetic field signals on the surfaces of both smooth and defective specimens under different loads were recordedwith a TSC-2 M-8 magnetometer. The distribution of the piezomagnetic field and its evolution with increasing load w-ere analyzed. Results demonstrate that piezomagnetic signals can be used to identify defects, while the presence of defects significantly alters the distribution of piezomagnetic signals in smooth regions. A comparative study of piezomagnetic signal differences among specimens with different orientations confirmed the anisotropy of piezomagnetic properties. Furthermore, the microscopic mechanism underlying the anisotropic evolution of the piezomagnetic field was discussed. It was found that characteristic parameters quantifying piezomagnetic properties exhibit a strong linear correlation with WAAM steel orientation. Notably, during incremental loading, the relationship between characteristic parameters and specimen directionunderwent a reversal. These findings advance the understanding of piezomagnetic behavior in additively manufactured steel and demonstrate potential for piezomagnetism-based stress assessment and defect detection applications.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"630 ","pages":"Article 173452"},"PeriodicalIF":3.0,"publicationDate":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144896345","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}

{"title":"Magnetic and transport properties of nanoscale Ni2MnIn thin films","authors":"Raghad S.H. Saqat ,&nbsp;Subhadeep Datta ,&nbsp;Ian L. Pegg ,&nbsp;John Philip","doi":"10.1016/j.jmmm.2025.173457","DOIUrl":"10.1016/j.jmmm.2025.173457","url":null,"abstract":"<div><div>Ni₂MnIn Heusler alloys have attracted significant attention due to their intriguing magnetic and transport properties, which are closely tied to their structural and electronic characteristics. In this study, the magnetic and electrical transport behaviors of Ni₂MnIn thin films have been systematically investigated. The alloy crystallizes in a cubic L2₁ structure and exhibits a second-order ferromagnetic to paramagnetic phase transition near room temperature, with a Curie temperature around 310 K. Magnetic measurements reveal long-range ferromagnetic ordering consistent with mean field theory, supported by critical exponent and magnetic entropy analyses. Electrical resistivity measurements show typical metallic behavior up to the magnetic transition temperature from low temperature, followed by a noticeable decrease in resistivity, attributed to reduced magnetic scattering. The alloy also displays negative magnetoresistance, which increases with applied magnetic field strength, indicating a reduction of spin-dependent scattering. These combined magnetic and transport characteristics, along with a significant magnetocaloric effect, position Ni₂MnIn as a promising candidate for spintronic and magnetocaloric applications.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"630 ","pages":"Article 173457"},"PeriodicalIF":3.0,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144890036","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}

{"title":"Effect of transverse magnetic annealing on the surface texture and magnetization process of FeSiBNbCuP nanocrystalline alloys","authors":"Chunyang Mu ,&nbsp;Qian Ding ,&nbsp;Lining Pan ,&nbsp;Haoran Ma ,&nbsp;Mengran Su ,&nbsp;Zengkun Tian ,&nbsp;Aina He ,&nbsp;Yaqiang Dong ,&nbsp;Deren Li ,&nbsp;Qikui Man ,&nbsp;Jiawei Li","doi":"10.1016/j.jmmm.2025.173461","DOIUrl":"10.1016/j.jmmm.2025.173461","url":null,"abstract":"<div><div>Transverse magnetic field annealing (TA) utilizes magneto-thermal coupling to regulate domain dynamics, enabling precise tuning of the soft magnetic properties in Fe-Si-B-Cu-Nb nanocrystalline alloys. Despite the industrial potential of low-cost Fe-based alloys, pervasive surface crystallization phenomenon significantly hinders the optimization of soft magnetic properties and limits their applicability in high-frequency devices. To address these challenges, this study systematically explores texture evolution and anisotropy fields, focusing on surface-textured cores. Comparative annealing experiments (zero magnetic field annealing, ZA; transverse magnetic field annealing, TA) were conducted to analyze the effects of texture content, grain orientation, and domain motion on soft magnetic properties. Compared to ZA, TA induces straighter domain walls with reduced curvature, shifting the dominant magnetization mechanism from domain wall displacement to coherent rotation, which is attributed to the enhanced uniaxial anisotropy induced by the magnetic field. The rotation-dominated domain dynamics reduces excess eddy current loss and enhances permeability at high frequency, demonstrating the potential of the TA core for high-frequency devices.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"630 ","pages":"Article 173461"},"PeriodicalIF":3.0,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144890038","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}

{"title":"Influence of particle shape on magnetic behavior of SrFe12O19/CoxFey composites","authors":"V. Bilovol ,&nbsp;A. Quesada ,&nbsp;A. Kmita ,&nbsp;D. Lachowicz ,&nbsp;M. Gajewska","doi":"10.1016/j.jmmm.2025.173454","DOIUrl":"10.1016/j.jmmm.2025.173454","url":null,"abstract":"<div><div>In this study, we investigate the magnetic properties of magnetically hard/soft composites, specifically SrFe₁₂O₁₉/Co₂Fe and SrFe₁₂O₁₉/CoFe₂. The precursor materials were combined in a 90:10 mass ratio using both manual mixing and ultrasonication methods. The SrFe₁₂O₁₉/CoFe₂ composite exhibited a notable improvement in remanent magnetization—approximately 12% higher than that of pure SrFe₁₂O₁₉. Transmission electron microscopy images suggest that the enhanced performance may be attributed to the elongated morphology of the CoFe₂ nanoparticles, in contrast to the more spherical Co₂Fe particles. This anisotropic shape likely contributes to improved magnetic properties through enhanced shape anisotropy and better alignment of the soft magnetic phase within the composite matrix.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"630 ","pages":"Article 173454"},"PeriodicalIF":3.0,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144890113","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}