Journal of Magnetism and Magnetic Materials最新文献

{"title":"Corrosion resistance of Al2O3/Cr composite coating on sintered NdFeB magnet","authors":"Z.H. Rao,&nbsp;J.L. Xu,&nbsp;X.H. Zhang,&nbsp;J. Huang,&nbsp;J.M. Zhang,&nbsp;J.M. Luo","doi":"10.1016/j.jmmm.2025.172895","DOIUrl":"10.1016/j.jmmm.2025.172895","url":null,"abstract":"<div><div>To improve the corrosion resistance of sintered NdFeB magnets, a composite coating of Al₂O₃/Cr was applied to the surface of the magnet using a combination of cathodic plasma electrolytic deposition (CPED) and double glow plasma deposition techniques. The morphologies of the surface and fractured cross-section, as well as the phase composition and corrosion resistance of the composite coatings, were examined through SEM, XRD, accelerated corrosion immersion test, and electrochemical tests, respectively. The influence of the composite coating on the magnetic characteristics of sintered NdFeB magnet was also evaluated. The results show that the Al₂O₃ intermediate layer is completely covered by the Cr coating and the interface between the Al₂O₃ layer and the Cr layer forms a mechanical interlocking effect. The surface of the Al₂O₃/Cr coating exhibits a hump cellular-like structure with the preferred orientation of Cr (200) plane. Compared with uncoated NdFeB magnet, the maximum magnetic energy product of the Al₂O₃/Cr composite coated sample decreases by 11.1 %. In the sulfuric acid immersion test, the weight loss of the Al₂O₃/Cr coated sample is only 15.04 % of that of the uncoated sample. The Al₂O₃/Cr coated NdFeB sample also demonstrates superior corrosion resistance compared to both the uncoated and Cr coated samples in the electrochemical tests. The Al₂O₃/Cr composite coating provides a new strategy for improving the corrosion resistance of sintered NdFeB magnets.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"619 ","pages":"Article 172895"},"PeriodicalIF":2.5,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143474620","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 Al or Cr substitution on structure and magnetic properties of barium hexaferrites prepared by hydrothermal method","authors":"A.Yu. Mironovich ,&nbsp;V.G. Kostishin ,&nbsp;H.I. Al-Khafaji ,&nbsp;E.S. Savchenko ,&nbsp;A.I. Ril ,&nbsp;R.I. Shakirzyanov ,&nbsp;M.A. Sysoev","doi":"10.1016/j.jmmm.2025.172896","DOIUrl":"10.1016/j.jmmm.2025.172896","url":null,"abstract":"<div><div>In this study, BaFe_12-xCr_xO₁₉ and BaFe_12-xAl_xO₁₉ (x = 0.0, 0.1, 0.3 and 0.4) powders were prepared by a hydrothermal method followed by annealing. The incorporation of Cr and Al in the hexaferrite structure was confirmed by elemental analysis and the results of Rietveld refinement of X-ray diffraction patterns, which revealed a decrease in the lattice volume with increasing x. Based on Mössbauer spectroscopy and magnetic measurements, the lack of Fe³⁺ was observed in the 12k site for BaFe_12-xAl_xO₁₉ samples and in the 12k, 4f₁ and 4f₂ sites for BaFe_12-xCr_xO₁₉ samples. With increasing substitution, the magnetic parameters of Al-substituted hexaferrites varied slightly, possibly due to limited incorporation of Al³⁺. At the same time, a significant decrease in H_c was observed for Cr-substituted samples (5629 Oe for x = 0 and 2092 Oe for x = 0.4). Electron microscopy revealed that the substitution of Fe³⁺ with Al³⁺ had no significant effect on crystallite morphology. The substitution of Fe³⁺ with Cr³⁺ leads to the thinning and widening of the plate-like grains of hexaferrite. This could be one of the reasons for the decrease in coercivity.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"619 ","pages":"Article 172896"},"PeriodicalIF":2.5,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143463347","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":"The pulse magnetic field method for measuring magnetization curves of silicon steel under highly saturated state","authors":"Xiang Zhao,&nbsp;Yapeng Jiang,&nbsp;Yu Wang,&nbsp;Junquan Chen","doi":"10.1016/j.jmmm.2025.172873","DOIUrl":"10.1016/j.jmmm.2025.172873","url":null,"abstract":"<div><div>Silicon steel in high power density motors typically operates at high saturation points (above 2 T). However, existing magnetic measurement methods currently struggle to accurately measure the characteristics under highly saturated conditions. Therefore, this paper proposes a Pulse Magnetic Field (PMF) method, which generates a sufficient excitation magnetic field to measure the magnetic properties of silicon steel under highly saturated states. Firstly, the feasibility of the method is proved by principle and simulation. Secondly a signal processing method is proposed to solve the noise, zero drift, and localization. Then the experiments show that the PMF method can generate a magnetic field of over 1,40,000 A/m, causing the silicon steel to reach a high saturation state, over 2 T. Finally, the effect of capacitance value on the measurement of the intrinsic magnetization curve is explored. The test results show that the PMF method can quickly and accurately measure the intrinsic magnetization curve of silicon steel materials under high saturation. Compared with the existing method, the error is about 1 %.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"620 ","pages":"Article 172873"},"PeriodicalIF":2.5,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143521149","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":"Preparation of highly stable magnetic fluid and analysis of dynamic sealing characteristics of large-diameter eccentric shafts","authors":"Xiude Yi ,&nbsp;Buhe Bateer ,&nbsp;Feihu Zhang ,&nbsp;Qiuyang Guo","doi":"10.1016/j.jmmm.2025.172893","DOIUrl":"10.1016/j.jmmm.2025.172893","url":null,"abstract":"<div><div>A highly stable magnetic fluid with high saturation magnetization is created, and a dynamic magnetic fluid sealing device for large shaft diameters is designed. This device features a sealing diameter of 380 mm and a sealing gap of 0.5 mm. The study evaluates the temperature rise rate, sealing capability, and long-term sealing performance under various conditions, including the magnetic fluid’s saturation magnetization, linear velocity, sealing gap, and pole tooth width. The structural parameters of the dynamic magnetic fluid seal device are optimized, resulting in a dynamic seal that can operate sustainably under conditions of a maximum shaft deflection of 0.25 mm, a maximum linear velocity of 23.8 m/s, and a sealing vacuum of 1300 Pa.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"619 ","pages":"Article 172893"},"PeriodicalIF":2.5,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143463350","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":"Improvement of the spin-valley polarization and tunneling magnetoresistance in magnetic silicene superlattices by means of aperiodic Kolakoski order","authors":"J.G. Rojas-Briseño,&nbsp;P. Villasana-Mercado,&nbsp;S. Molina-Valdovinos,&nbsp;R. Rodríguez-González,&nbsp;I. Rodríguez-Vargas","doi":"10.1016/j.jmmm.2025.172871","DOIUrl":"10.1016/j.jmmm.2025.172871","url":null,"abstract":"<div><div>Aperiodic order is quite relevant in science and technology. The aperiodic order is characterized by the so-called aperiodic sequences. Among the most important sequences we can find the Fibonacci, Thue–Morse, and Cantor sequences. The Thue–Morse and Cantor sequence have been instrumental in improving the spin-valley polarization and tunneling magnetoresistance (TMR) of magnetic silicene superlattices (MSSLs). Here, we study the impact of aperiodic Kolakoski order on the spin-valley polarization and TMR of MSSLs. The spin-valley polarization and TMR of Kolakoski (K-) MSSLs are compared with the ones of periodic (P-), Thue–Morse (TM-), and Cantor (C-) MSSLs. We find that the higher degree of disorder of the Kolakoski sequence reduces the total conductance of the antiparallel magnetization configuration, resulting in an effective enhancement of the TMR. Also, the aperiodic Kolakoski order gives rise to energy regions of two well-defined spin-valley polarization states accessible by switching the magnetization direction. The aperiodic Kolakoski order in conjunction with structural asymmetry can optimize the spin-valley polarization and TMR of MSSLs. The spin-valley polarization and TMR capabilities of K-MSSLs are superior than the ones of P-, TM-, and C-MSSLs.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"619 ","pages":"Article 172871"},"PeriodicalIF":2.5,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143463348","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":"Temperature dependence of spin-polarization in FIS graphene junction","authors":"Hamidreza Emamipour","doi":"10.1016/j.jmmm.2025.172870","DOIUrl":"10.1016/j.jmmm.2025.172870","url":null,"abstract":"<div><div>We study the effect of temperature on spin polarization in graphene-based ferromagnet insulator superconductor (FIS) junctions, theoretically. Within the framework of BTK (Blonder Tinkham Klapwijk) theory we find that when <span><math><msub><mrow><mi>E</mi></mrow><mrow><mi>F</mi></mrow></msub></math></span> is selected near to <span><math><msub><mrow><mi>E</mi></mrow><mrow><mi>x</mi></mrow></msub></math></span> (where <span><math><msub><mrow><mi>E</mi></mrow><mrow><mi>F</mi></mrow></msub></math></span> and <span><math><msub><mrow><mi>E</mi></mrow><mrow><mi>x</mi></mrow></msub></math></span> represent Fermi energy and exchange field in the ferromagnet region) and temperature approaches to <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span> spin-polarization gets 100%. This case implies the spin-polarization is generated by just one spin species i.e. spin-up current, (<span><math><msub><mrow><mi>I</mi></mrow><mrow><mi>u</mi></mrow></msub></math></span>). We also obtain a phase diagram <span><math><mrow><msub><mrow><mi>E</mi></mrow><mrow><mi>x</mi></mrow></msub><mo>−</mo><mi>T</mi></mrow></math></span> which distinguishes SAR (specular Andreev reflection) from NAR (normal Andreev reflection). Therefore, the proposed junction may be applied not only to create huge spin-polarization which is significant in spintronic-industry but also to discriminate SAR and NAR from each other which is important in fundamental condensed matter physics.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"618 ","pages":"Article 172870"},"PeriodicalIF":2.5,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143437262","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":"Open static magnetic cloak based on DC magnetic metamaterials","authors":"Yangrong Chen ,&nbsp;Hanchuan Chen ,&nbsp;Fei Sun ,&nbsp;Yichao Liu ,&nbsp;Xiaoxiao Wu ,&nbsp;Haitao Li ,&nbsp;Zhixing Zhang ,&nbsp;Qianhan Sun","doi":"10.1016/j.jmmm.2025.172885","DOIUrl":"10.1016/j.jmmm.2025.172885","url":null,"abstract":"<div><div>Due to the significant applications of static magnetic field invisibility in avoiding metal detector detection, it has received extensive attention in recent years. However, most existing methods (e.g., multilayer closed structures based on DC magnetic metamaterials) achieve closed invisibility, hindering the exchange of information and materials between the cloak’s interior and the external environment. In this study, a DC magnetic field shifter is designed based on transformation magnetostatics and then combined with a specially designed closed DC magnetic cloak with a hole to develop an open static magnetic cloak. Numerical simulations verify the invisibility effect and multi-directional effectiveness of this open cloak. Finally, effective medium theory is utilized to achieve the open static magnetic field cloak by arranging isotropic media specifically, whose effectiveness is validated through numerical simulations.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"619 ","pages":"Article 172885"},"PeriodicalIF":2.5,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143453569","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":"The role of W seed and spacer layers on the magnetic properties of Co/Pt multilayers","authors":"M. Tokaç ,&nbsp;H. Pişkin ,&nbsp;G. Ekinci ,&nbsp;B. Özkal ,&nbsp;S. Kazan","doi":"10.1016/j.jmmm.2025.172869","DOIUrl":"10.1016/j.jmmm.2025.172869","url":null,"abstract":"<div><div>The selection of seed and spacer layers is critical in influencing the magnetic properties of thin films, where these layers impact the microstructure, interface quality, and overall magnetic behavior of the thin films. The magnetic properties of Co/Pt multilayers have been investigated where the choice of seed and spacer layers is crucial for tailoring their magnetic properties. These layers influence the interfacial structure, and electronic environment, all of which contribute to variations in the effective demagnetizing field, g-factor, saturation magnetization, and perpendicular surface anisotropy constants. Ferromagnetic resonance has been used to investigate the enhancement of the Gilbert damping parameter, where the damping parameter is higher for the Cu/Co/Pt multilayers across the entire Co thickness range. In contrast, the presence of W layers on both sides of the Co layer leads to a reduction in the damping parameter. The higher spin-mixing conductance in the Co/Pt structure is linked to stronger SOC and enhanced orbital hybridization at the Co/Pt interface. As a consequence of their effects on spin–orbit interactions, spin-pumping efficiency, and interfacial quality, our results emphasize the critical role that interface characteristics play in improving damping in Co/Pt systems.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"618 ","pages":"Article 172869"},"PeriodicalIF":2.5,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143437263","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":"Characterization and evaluation of commercial tracers for x-space magnetic particle imaging","authors":"Eric Daniel Imhoff ,&nbsp;Andrii Melnyk ,&nbsp;Carlos M. Rinaldi-Ramos","doi":"10.1016/j.jmmm.2025.172889","DOIUrl":"10.1016/j.jmmm.2025.172889","url":null,"abstract":"<div><div>Commercial magnetic particle imaging (MPI) tracers are utilized for many applications including as reference materials for comparing tracer performance, but comparative measurements of many tracers on a single imaging platform are uncommon. This study uses relaxometry and 2D imaging in a pre-clinical MOMENTUM scanner to characterize and evaluate the performance of six common commercial tracers for MPI: Synomag-D Plain, Synomag-D NH2, Synomag-D PEG, Perimag, Vivotrax, and Vivotrax Plus. Repeated measurements of samples showed considerable variability while inter-sample differences were generally negligible. Sensitivity between the two modes is strongly correlated while resolution of the two modes was only moderately correlated. Further, relaxometric measurements tend to predict better resolution than is achieved in 2D imaging. All evaluated tracers have resolutions within 1 mm of each other on the MOMENTUM imager. These results illustrate that relaxometer measurements can be used to broadly predict MPI performance but do not accurately recreate the physical processes or differences in hardware and software of MPI. This study provides MPI measurements of tracers that may be useful to researchers while highlighting the challenges of making comparisons between tracers due to variation within samples and across different measurement techniques and instruments.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"620 ","pages":"Article 172889"},"PeriodicalIF":2.5,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143521152","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":"Nonvolatile electrical control of magnetism of monolayer C2N via carrier doping in a two dimensional heterostructure","authors":"Changwei Wu,&nbsp;Yun Xie,&nbsp;Weiping Gong","doi":"10.1016/j.jmmm.2025.172857","DOIUrl":"10.1016/j.jmmm.2025.172857","url":null,"abstract":"<div><div>Nonvolatile electrical control of magnetism in two-dimensional (2D) van der Walls heterostructure has sparked significant interest for both understanding the fundamental magnetoelectric physics and device application. Here, using the first-principles calculations, we propose a new multiferroic van der Waals (vdW) heterostructure <span><math><mrow><msub><mrow><mi>C</mi></mrow><mrow><mn>2</mn></mrow></msub><mi>N</mi></mrow></math></span>/<span><math><mrow><msub><mrow><mi>In</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>Se</mi></mrow><mrow><mn>3</mn></mrow></msub></mrow></math></span> based on C₂N and ferroelectric (FE) In₂Se₃ relying on no-transition metals. Upon electron doping, <span><math><mrow><msub><mrow><mi>C</mi></mrow><mrow><mn>2</mn></mrow></msub><mi>N</mi></mrow></math></span>/<span><math><mrow><msub><mrow><mi>In</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>Se</mi></mrow><mrow><mn>3</mn></mrow></msub></mrow></math></span>-<span><math><mrow><mi>P</mi><mi>↓</mi></mrow></math></span> maintains nonmagnetic nature, but <span><math><mrow><msub><mrow><mi>C</mi></mrow><mrow><mn>2</mn></mrow></msub><mi>N</mi></mrow></math></span>/<span><math><mrow><msub><mrow><mi>In</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>Se</mi></mrow><mrow><mn>3</mn></mrow></msub></mrow></math></span>-<span><math><mrow><mi>P</mi><mi>↑</mi></mrow></math></span> changes into ferromagnetic state. Moreover, the magnetoelectric coupling is enhanced via engineering interlayer distance of <span><math><mrow><msub><mrow><mi>C</mi></mrow><mrow><mn>2</mn></mrow></msub><mi>N</mi></mrow></math></span>/<span><math><mrow><msub><mrow><mi>In</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>Se</mi></mrow><mrow><mn>3</mn></mrow></msub></mrow></math></span>. The magnetic moment of <span><math><mrow><msub><mrow><mi>C</mi></mrow><mrow><mn>2</mn></mrow></msub><mi>N</mi></mrow></math></span>/<span><math><mrow><msub><mrow><mi>In</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>Se</mi></mrow><mrow><mn>3</mn></mrow></msub></mrow></math></span>-<span><math><mrow><mi>P</mi><mi>↑</mi></mrow></math></span> reaches 1.0 <span><math><msub><mrow><mi>μ</mi></mrow><mrow><mi>B</mi></mrow></msub></math></span>/e over the electron concentration ranging from 0.1 to 0.4 e per unit cell at an interlayer distance of 3.2 Å. Our results broaden the materials design space for 2D multiferroic materials.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"618 ","pages":"Article 172857"},"PeriodicalIF":2.5,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143429137","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}