Journal of Magnetism and Magnetic Materials最新文献

{"title":"Comparison of pinning potentials, depinning currents and scalability for domain wall-based synapses with various pinning structures","authors":"Guntas Kaur,&nbsp;Tanmoy Pramanik","doi":"10.1016/j.jmmm.2025.173280","DOIUrl":"10.1016/j.jmmm.2025.173280","url":null,"abstract":"<div><div>Domain wall (DW) based magnetic tunnel junctions (MTJ) are one of the promising candidates for memristive artificial synapses. Various domain wall tracks have recently been studied, and different geometric configurations for pinning domain walls have been proposed. Geometric pinning helps to control the domain wall (DW) motion along the track and quantizes the conductance of the DW-MTJ to specific values. This work compares various geometric pinning options in terms of thermal stability, depinning currents, and programming reliability under random thermal fluctuations for scaled device dimensions. Results show that all pinning configurations can meet the thermal stability limits required for non-volatile operation if the device is designed appropriately. However, depending on the pinning geometry, depinning current requirements can vary considerably. Reliable programming with good linearity can be achieved for all of the studied configurations. Additionally, one-dimensional pinning potentials suitable for a compact model of DW motion are obtained for each pinning geometry. The results could provide valuable guidelines for designing DW tracks with scaled dimensions, thermally stable quantized conductance states, and highly reliable programming behavior.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"629 ","pages":"Article 173280"},"PeriodicalIF":2.5,"publicationDate":"2025-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144471054","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":"A closed-form formula-based method for magnetic dipole localization in a constant magnetic field by measurement of its magnetic field vectors and magnetic gradient tensors","authors":"Massimo Stefanoni ,&nbsp;Ákos Odry ,&nbsp;Peter Sarcevic","doi":"10.1016/j.jmmm.2025.173313","DOIUrl":"10.1016/j.jmmm.2025.173313","url":null,"abstract":"<div><div>The problem of dipole localization and its parameter estimation has been widely investigated. In the literature, various approaches have been proposed, including iterative methods and resolution schemes based on inverse formulas. This paper introduces the Closed-form Formula-based Method (CFM), which addresses the dipole localization problem when the source is placed in the Earth’s magnetic field, assumed to be constant within the region of interest. The CFM is based on a modified version of the Yin formula that is a closed-form expression originally developed to estimate the position of a dipole in the absence of a constant magnetic field. The proposed method utilizes this modified Yin formula in combination with a specific magnetometer array configuration designed to measure both gradients and magnetic field values, along with a selection algorithm. The concept was tested by simulations in which different dipole parameters and different positions are tested to verify all possible configurations. Both the Yin formula and the CFM were simulated in MATLAB by developing scenarios in which infinitesimal gradient schemes were considered. Additionally, the CFM was tested by taking into account a finite gradient scheme, the effect of white noise, different trajectories in space, and different strengths of the dipole. Results show that the CFM can be used in all configurations in which the Yin formula does not work, and that it localizes a 100 Am² dipole at a distance of 3 m, with a white noise of 0.01 nT as a standard deviation, providing a mean and maximum absolute error of 0.01 m and 0.03 m, respectively.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"629 ","pages":"Article 173313"},"PeriodicalIF":2.5,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144366231","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":"Enhancement in structural order and half-metallicity by V substitution for Co in Co2MnAl alloy","authors":"Madhav M. Bhat,&nbsp;Perumal Alagarsamy,&nbsp;Ananthakrishnan Srinivasan","doi":"10.1016/j.jmmm.2025.173308","DOIUrl":"10.1016/j.jmmm.2025.173308","url":null,"abstract":"<div><div>In an attempt to enhance the spin polarization of Co₂MnAl Heusler alloys, a series of bulk Co_2-xMnV_xAl (for <em>x</em> = 0.0, 0.25, and 0.50) alloys have been prepared and studied. Structural investigations revealed a <em>B</em>2-type partially disordered structure in the alloys with <em>x</em> = 0.0 and 0.25, whereas the alloy with <em>x</em> = 0.50 displayed <em>L</em>2₁–type structure with high ordering. The saturation magnetization values of 3.91 ± 0.04, 2.45 ± 0.04, and 1.48 ± 0.03 μ_B/f.u. were observed at 10 K for the alloys with <em>x</em> = 0.0, 0.25, and 0.50, respectively. With progressive incorporation of V for Co, the Curie temperature decreased from 690 K to 533 K along with a decrease in effective magnetic anisotropy constant. The first-principles calculations predict a rise in spin polarization from ∼69 % for <em>x</em> = 0.0 to 100 % for the alloy with <em>x</em> = 0.50. The enhancement in spin polarization predicted in Co_1.5MnV_0.5Al alloy was experimentally validated by the appropriate Rhodes-Wohlfarth ratio evaluated for this alloy, which projects it as a promising contender for applications in spintronic devices.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"629 ","pages":"Article 173308"},"PeriodicalIF":2.5,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144366230","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":"Non-coplanar antisymmetric exchange in the ferromagnet PbMnBO4","authors":"S.N. Martynov","doi":"10.1016/j.jmmm.2025.173283","DOIUrl":"10.1016/j.jmmm.2025.173283","url":null,"abstract":"<div><div>To determine the direction of DM vector in the magnets with two non-coplanar super-exchange paths, a criterion based on an asymmetry of distribution of ligands between interacting spins is proposed. The direction of DM vector in <span><math><msub><mrow><mi>PbMnBO</mi></mrow><mrow><mn>4</mn></mrow></msub></math></span> corresponds to structural formula following from this criterion. The exchange paths, allowing the existence of the two-bridge DM interaction between neighboring <span><math><msup><mrow><mi>Mn</mi></mrow><mrow><mn>3</mn><mo>+</mo></mrow></msup></math></span>-ions in the chains, are considered. The possible mechanisms of antisymmetric exchange via two ligands in this crystal are discussed.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"629 ","pages":"Article 173283"},"PeriodicalIF":2.5,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144338344","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":"High-frequency magnetic properties of Fe-Si-B-Cu-Zr nanocrystalline soft magnetic composites with YIG ferrite insulating layer","authors":"Zhihui Xu ,&nbsp;Jing Li ,&nbsp;Xiaoling Peng ,&nbsp;Shan Tao ,&nbsp;Jingcai Xu ,&nbsp;Bo Hong ,&nbsp;Xinqing Wang","doi":"10.1016/j.jmmm.2025.173310","DOIUrl":"10.1016/j.jmmm.2025.173310","url":null,"abstract":"<div><div>The present study utilized Y₃Fe₅O₁₂ (YIG) ferrites as a coating on Fe-Si-B-Cu-Zr nanocrystalline magnetic powder to fabricate soft magnetic composites (SMCs). The influence of YIG content and annealing temperature on the magnetic properties of Fe-Si-B-Cu-Zr/YIG SMCs was investigated. It was revealed that an appropriate amount of YIG in the composite could enhance the permeability and its resistance to DC bias, while reducing eddy current loss. The results demonstrated that the Fe-Si-B-Cu-Zr/YIG SMCs coated with 1.0 wt% YIG exhibited good comprehensive magnetic properties, with a permeability of 33.8, 86.1 % retention under a DC bias of 100 Oe, and a 53.1 % reduction in eddy current loss to 13.86 mW/cm³ at 500 kHz and 10 mT. Besides, the optimal annealing temperature for achieving decrease core loss and maximum permeability was determined to be 500℃ for the Fe-Si-B-Cu-Zr/YIG SMCs. This study demonstrates a promising coating material to enhance the high-frequency magnetic properties of nanocrystalline soft magnetic composite.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"629 ","pages":"Article 173310"},"PeriodicalIF":2.5,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144338346","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":"Topological states in magnetic multilayers with hybrid anisotropy and Dzyaloshinskii–Moriya interaction","authors":"Z.V. Gareeva ,&nbsp;V.V. Filippova","doi":"10.1016/j.jmmm.2025.173307","DOIUrl":"10.1016/j.jmmm.2025.173307","url":null,"abstract":"<div><div>Magnetic multilayers with engineered anisotropy and controlled Dzyaloshinskii–Moriya interaction offer a versatile platform for stabilizing complex three-dimensional topological structures. In this article, we investigate the magnetic states in an exchanged-coupled four-layer ferromagnetic film composed of layers with perpendicular and in-plane magnetic anisotropies. By introducing the Dzyaloshinskii–Moriya interaction into single layer and bi-layer, we demonstrate the stabilization of a variety of topological textures in the film during magnetization processes. Using micromagnetic simulations, we show that tuning the Dzyaloshinskii–Moriya interaction strength and anisotropy of individual layers governs the emergence of distinct topological phases, including conical skyrmions, kπ-skyrmion tubes (k = 1, 2), Bloch points, and chiral bobbers. We identify the conditions necessary for stabilizing these states and construct phase diagrams mapping the field-driven transitions. These results provide insight into the mechanisms of topological state formation and may contribute to the development of magnetic multilayer systems for multi-bit memory and neuromorphic computing applications.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"629 ","pages":"Article 173307"},"PeriodicalIF":2.5,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144338343","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":"Insight into half-metallicity, electronic structure, and thermal transport properties of FeRhGa1−xAsx Heusler alloys","authors":"Oksana Pavlukhina,&nbsp;Vladimir Sokolovskiy,&nbsp;Danil Baigutlin,&nbsp;Vasiliy Buchelnikov,&nbsp;Ilya Zotov","doi":"10.1016/j.jmmm.2025.173268","DOIUrl":"10.1016/j.jmmm.2025.173268","url":null,"abstract":"<div><div>In this work, we study electronic structure, magnetic, and transport properties of FeRhGa<span><math><msub><mrow></mrow><mrow><mn>1</mn><mo>−</mo><mi>x</mi></mrow></msub></math></span>As<span><math><msub><mrow></mrow><mrow><mi>x</mi></mrow></msub></math></span> half-Heusler alloys (<span><math><mrow><mn>0</mn><mo>≤</mo><mi>x</mi><mo>≤</mo><mn>1</mn></mrow></math></span>) using the extensive density functional calculations. We find that the ground state of compounds with <span><math><mrow><mn>0</mn><mo>≤</mo><mi>x</mi><mo>≤</mo><mn>0</mn><mo>.</mo><mn>75</mn></mrow></math></span> is the cubic <span><math><mi>γ</mi></math></span> phase, while FeRhAs possesses the cubic <span><math><mi>β</mi></math></span> phase. The main difference between the two structures is an occupation of four by 8 tetrahedral sites by Ga and Rh, respectively. The mechanical and thermodynamic stability of the ground state structures is confirmed using the predicted elastic constants and phonon spectra. The parent FeRhGa and FeRhAs alloys demonstrate 66 and 74 % spin polarization, respectively, while FeRhGa_0.5As_0.5 reveals the robust half-metallic behavior. In this case, the 100 % spin polarization is retained under compressive pressure up to 5 GPa. The FeRhGa_0.5As_0.5 alloy possesses the thermal conductivity (<span><math><mrow><msub><mrow><mi>κ</mi></mrow><mrow><mi>l</mi><mi>a</mi><mi>t</mi></mrow></msub><mo>≈</mo><mn>11</mn></mrow></math></span> W/(m<span><math><mo>×</mo></math></span>K)), whereas the parent compounds FeRhGa and FeRhAs are characterized by <span><math><msub><mrow><mi>κ</mi></mrow><mrow><mi>l</mi><mi>a</mi><mi>t</mi></mrow></msub></math></span> of 12.7 and 7.45 W/(m<span><math><mo>×</mo></math></span>K) at 300 K, correspondingly. To explore the possible thermoelectric properties achievable in half-metallic FeRhGa_0.5As_0.5, we investigate the relationship between the optimal carrier concentration, power factor, and figure of merit <span><math><mrow><mi>Z</mi><mi>T</mi></mrow></math></span>. It is shown that for <span><math><mi>n</mi></math></span>-type doping about 10²² cm⁻³, FeRhGa_0.5As_0.5 demonstrates several times higher thermoelectric properties than those of <span><math><mi>p</mi></math></span>-type doping especially in a case of the temperature dependent relaxation time approach. Our results pave the way for further research into FeRhGa<span><math><msub><mrow></mrow><mrow><mn>1</mn><mo>−</mo><mi>x</mi></mrow></msub></math></span>As<span><math><msub><mrow></mrow><mrow><mi>x</mi></mrow></msub></math></span> alloys in the search for improved spintronic and thermoelectric materials for use in applications where high spintronic and thermoelectric performance is required.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"629 ","pages":"Article 173268"},"PeriodicalIF":2.5,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144366232","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":"Quadrupolar phases and plateau states in skewed ladders","authors":"Sambunath Das ,&nbsp;Dayasindhu Dey ,&nbsp;Manoranjan Kumar ,&nbsp;S. Ramasesha","doi":"10.1016/j.jmmm.2025.173262","DOIUrl":"10.1016/j.jmmm.2025.173262","url":null,"abstract":"<div><div>Two legged skewed spin-<span><math><mfrac><mrow><mn>1</mn></mrow><mrow><mn>2</mn></mrow></mfrac></math></span> ladders are frustrated and exhibit exotic quantum phases in ground state due to strong quantum fluctuations and competing spin exchanges. Here, we study ground state properties of a spin-<span><math><mfrac><mrow><mn>1</mn></mrow><mrow><mn>2</mn></mrow></mfrac></math></span> Heisenberg model on 3/4, 3/5 and 5/5 skewed ladders in the presence of a Zeeman magnetic field, <span><math><mi>B</mi></math></span>, using exact diagonalization and the density matrix renormalization group method. We note the existence of plateaus at <span><math><mrow><mi>m</mi><mo>=</mo></mrow></math></span> 1/3 and 2/3 for 3/4 skewed ladder, at <span><math><mrow><mi>m</mi><mo>=</mo></mrow></math></span> 1/4, 1/2, and 3/4 for 3/5 skewed ladder, and at <span><math><mrow><mi>m</mi><mo>=</mo><mn>0</mn></mrow></math></span>, 1/3, and 2/3 for 5/5 skewed ladder, where <span><math><mi>m</mi></math></span> is the ratio of the observed magnetization (<span><math><mi>M</mi></math></span>) to the saturated magnetization (<span><math><msub><mrow><mi>M</mi></mrow><mrow><mi>max</mi></mrow></msub></math></span>). The plateau state is always a gapped state and the plateau width depends on the gap in the system. Surprisingly, the 3/4 and 5/5 skewed ladders show interesting quadrupolar or n-type spin nematic phases below the 1/3rd plateau, i.e, at very low magnetic fields. These two systems are unique as they host both a plateau and a quadrupolar phase at low magnetic fields. The linear variation of pitch angle of the spin with magnetization and behavior of binding energy of magnon pairs as function of magnetic field are also calculated in both the systems. We also study the contribution of the binding energy to two magnon condensate.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"629 ","pages":"Article 173262"},"PeriodicalIF":2.5,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144321469","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":"Floating performance of tiny non-magnetic particles in ferrofluids","authors":"Liu Li ,&nbsp;Decai Li ,&nbsp;Yunqi Guo","doi":"10.1016/j.jmmm.2025.173292","DOIUrl":"10.1016/j.jmmm.2025.173292","url":null,"abstract":"<div><div>Magnetic buoyancy, known as a kind of force that acts between ferrofluids and non-magnetic particles submerged in ferrofluids magnetized by an intense gradient magnetic field, is systematically characterized in this study. Based on Rosensweig’s expression for magnetic buoyancy force and the perturbed magnetic field assumption for tiny particles, the criteria of magnetic field intensity which allow the non-magnetic particles to float on ferrofluids are established. Experimental results demonstrate that if the gradient magnetic field intensity exceeds a critical value, non-magnetic particles submerged in ferrofluids can achieve stable levitation via magnetic buoyancy. The magnetic buoyancy can be effectively utilized to separate mixed powders of micro-sized lead (Pb) and silicone dioxide (SiO₂), demonstrating potential for sustainable metal recycling in future applications.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"629 ","pages":"Article 173292"},"PeriodicalIF":2.5,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144306580","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":"Ultrafast spin dynamics and spin transport in ferromagnetic spin valve","authors":"V.N. Gridnev","doi":"10.1016/j.jmmm.2025.173247","DOIUrl":"10.1016/j.jmmm.2025.173247","url":null,"abstract":"<div><div>We analyze theoretically the recent experimental observation of laser-induced single-shot subpicosecond magnetization switching in rare-earth free spin valves. Using the Landau–Lifshitz–Bloch equation and Valet–Fert theory of spin transport in spin valve we numerically calculate the spin dynamics, including spin transport in spin-valves, upon incidence of a single laser pulse. We show that a single laser pulse can switch relative magnetizations of a pair of ferromagnetic layers between parallel and antiparallel configurations. Relation of our calculation to the experimental observation is discussed.</div></div>","PeriodicalId":366,"journal":{"name":"Journal of Magnetism and Magnetic Materials","volume":"629 ","pages":"Article 173247"},"PeriodicalIF":2.5,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144297144","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}